Variation of breast cancer risk among BRCA1/2 carriers

Context  The risk of breast cancer in BRCA1 and BRCA2 mutation carriers has been examined in many studies, but relatively little attention has been paid to the degree to which the risk may vary among carriers. Objectives  To determine the extent to which risks for BRCA1 and BRCA2 carriers vary with respect to observable and unobservable characteristics. Design, Setting, and Participants  Probands were identified from a population-based, case-control study (Women’s Environmental Cancer and Radiation Epidemiology [WECARE]) of asynchronous contralateral breast cancer conducted during the period of January 2000 to July 2004. Participants previously diagnosed with contralateral breast cancer or unilateral breast cancer were genotyped for mutations in BRCA1 and BRCA2. All participants had their initial breast cancer diagnosed during the period of January 1985 to December 2000, before the age of 55 years. Main Outcome Measure  Incidence of breast cancer in first-degree female relatives of the probands was examined and compared on the basis of proband characteristics and on the basis of variation between families. Results  Among the 1394 participants with unilateral breast cancer, 73 (5.2%) were identified as carriers of deleterious mutations (42 with BRCA1 and 31 with BRCA2). Among the 704 participants with contralateral breast cancer, 108 (15.3%) were identified as carriers of deleterious mutations (67 with BRCA1 and 41 with BRCA2). Among relatives of carriers, risk was significantly associated with younger age at diagnosis in the proband (P = .04), and there was a trend toward higher risk for relatives of contralateral breast cancer vs unilateral breast cancer participants (odds ratio, 1.4 [95% confidence interval, 0.8-2.4]; P = .28). In addition, there were significant differences in risk between carrier families after adjusting for these observed characteristics. Conclusion  There exists broad variation in breast cancer risk among carriers of BRCA1 and BRCA2 mutations.      

BRCA1 Mutations and Breast Cancer in the General Population: Analyses in Women Before Age 35 Years and in Women Before Age 45 Years With First-Degree Family History

Context.— Studies of high-risk families with multiple early-onset cases of breast cancer have been useful for assessing the type and spectrum of germline mutations on the BRCA1 gene, but do not provide guidance to women with modest family history profiles. Thus, studies of women from the general population are needed to determine the BRCA1 mutation frequency in women perceived to be at high risk, and to develop profiles of those most likely to be carriers. Objective.— To characterize frequency and spectrum of germline BRCA1 mutations in 2 categories of women identified via population-based studies hypothesized to be at increased risk of carrying such mutations: those diagnosed as having breast cancer before age 35 years and those diagnosed before age 45 years who have first-degree breast cancer family history. Design.— Study subjects were drawn from 2 population-based case-control studies of breast cancer in young women on the basis of their family history or their age of diagnosis. Cases were younger than 35 years or were younger than 45 years with first-degree family history at the time of breast cancer diagnosis and were ascertained via a population-based cancer registry, and controls (women without breast cancer) were identified via random-digit dialing. Setting.— Three counties in western Washington State. Main Outcome Measure.— BRCA1 germline mutations in study subjects identified in DNA from peripheral blood lymphocytes by single-strand conformation polymorphism analysis using primer pairs that span the BRCA1 coding region and intron-exon boundaries. Results.— Of 193 women diagnosed as having breast cancer before age 35 years, none of whom were selected on the basis of family history status, 12 (6.2%, 95% confidence interval [CI], 3.2%-10.6%) had germline BRCA1 mutations. In 208 women diagnosed before age 45 years who had first-degree breast cancer family history, 15 (7.2%, 95% CI, 4.1%-11.6%) had germline mutations in BRCA1. In both groups, there were variations in mutation frequency noted by age and by family history. Mutation frequency decreased with increasing age of diagnosis. Higher proportions of mutations were seen in cases with at least 1 relative diagnosed as having breast cancer before age 45 years, in cases with greater numbers of affected relatives, and those with ovarian cancer family history. Mutation frequency did not vary by bilateral breast cancer family history. No frameshift or nonsense mutations were observed in 71 control women with a first-degree family history, although missense changes of unknown significance were seen in cases and controls. Conclusions.— Women with BRCA1 germline mutations lacked a common family history profile. Also, a large proportion of the women with a first-degree breast cancer family history and women diagnosed as having breast cancer before age 35 years did not carry germline BRCA1 mutations. Hence, while early-onset disease and a strong breast cancer family history may be useful guidelines for checking BRCA1 status, these findings on women drawn from the general population suggest that it may be difficult to develop BRCA1 mutation screening criteria among women with modest family history profiles.      

Prevalence of BRCA1 and BRCA2 mutations in women diagnosed with ductal carcinoma in situ

Context  The distribution of BRCA1 and BRCA2 mutations in women diagnosed with noninvasive breast carcinoma is unknown. Objective  To estimate the BRCA1 and BRCA2 mutation prevalence in women with ductal carcinoma in situ (DCIS), unselected for age, family history, or ethnicity. Design, Setting, and Participants  The data were 369 DCIS cases diagnosed among female residents aged 20 to 79 years from the state of Connecticut between September 15, 1994, and March 14, 1998. These women were participants in a large population-based case-control study of breast carcinoma in situ. Telephone interviews were used to collect risk factor information and blood or buccal specimens were collected for BRCA1 and BRCA2 mutation testing. Main Outcome Measures  Prevalence of disease-associated mutations of BRCA1 and BRCA2 in women diagnosed with DCIS. Results  Three (0.8%) and 9 (2.4%) of 369 DCIS cases had disease-associated mutations in BRCA1 or BRCA2, respectively. One woman had a mutation in both genes (BRCA1 W321X and BRCA2 3398del5). Carriers were significantly more likely than noncarriers to report a first-degree (mother, sister, or daughter) family history of breast cancer (odds ratio [OR], 3.7; 95% confidence interval [CI], 1.1-12.4), as well as a personal history of ovarian cancer. In addition, carriers were more likely than noncarriers to be diagnosed at an early age (<50 years) (OR, 3.4; 95% CI, 1.0-11.7), as well as to report at least 1 first-degree relative diagnosed with breast cancer before 50 years (OR, 10.6; 95% CI, 3.0-37.0). Conclusions  Ductal carcinoma in situ is a part of the breast/ovarian cancer syndromes defined by BRCA1 and BRCA2, with mutation rates similar to those found for invasive breast cancer. These findings suggest that patients with breast cancer with an appropriate personal or family history of breast and/or ovarian cancer should be screened and followed according to high-risk protocols, regardless of whether they are diagnosed with in situ or invasive breast cancer.      

Clinicopathologic features of BRCA-linked and sporadic ovarian cancer

Context  Most hereditary ovarian cancers are associated with germline mutations in BRCA1 or BRCA2. Attempts to define the clinical significance of BRCA mutation status in ovarian cancer have produced conflicting results, especially regarding survival. Objective  To determine whether hereditary ovarian cancers have distinct clinical and pathological features compared with sporadic (nonhereditary) ovarian cancers. Design and Setting  Retrospective cohort study of a consecutive series of 933 ovarian cancers diagnosed and treated at our institution, which is a comprehensive cancer center as designated by the National Cancer Institute, over a 12-year period (December 1986 to August 1998). Patients  The study was restricted to patients of Jewish origin because of the ease of BRCA1 and BRCA2 genotyping in this ethnic group. From the 189 patients who identified themselves as Jewish, 88 hereditary cases were identified with the presence of a germline founder mutation in BRCA1 or BRCA2. The remaining 101 cases from the same series not associated with a BRCA mutation and 2 additional groups (Gynecologic Oncology Group protocols 52 and 111) with ovarian cancer from clinical trials (for the survival analysis) were included for comparison. Main Outcome Measures  Age at diagnosis, surgical stage, histologic cell type and grade, and surgical outcome; and response to chemotherapy and survival for advanced-stage (III and IV) cases. Results  Hereditary cancers were rarely diagnosed before age 40 years and were common after age 60 years, with mean age at diagnosis being significantly younger for BRCA1- vs BRCA2-linked patients (54 vs 62 years; P=.04). Histology, grade, stage, and success of cytoreductive surgery were similar for hereditary and sporadic cases. The hereditary group had a longer disease-free interval following primary chemotherapy in comparison with the nonhereditary group, with a median time to recurrence of 14 months and 7 months, respectively (P<.001). Those with hereditary cancers had improved survival compared with the nonhereditary group (P=.004). For stage III cancers, BRCA mutation status was an independent prognostic variable (P=.03). Conclusions  Although BRCA-associated hereditary ovarian cancers in this population have surgical and pathological characteristics similar to those of sporadic cancers, advanced-stage hereditary cancer patients survive longer than nonhereditary cancer patients. Age penetrance is greater for BRCA1-linked than for BRCA2-linked cancers in this population.      

Genetic testing in an ethnically diverse cohort of high-risk women: a comparative analysis of BRCA1 and BRCA2 mutations in American families of European and African ancestry

Context  Ten years after BRCA1 and BRCA2 were first identified as major breast cancer susceptibility genes, the spectrum of mutations and modifiers of risk among many ethnic minorities remain undefined. Objectives  To characterize the clinical predictors, spectrum, and frequency of BRCA1 and BRCA2 mutations in an ethnically diverse high-risk clinic population and to evaluate the performance of the BRCAPRO statistical model in predicting the likelihood of a mutation. Design, Setting, and Participants  Comparative analysis of families (white, Ashkenazi Jewish, African American, Hispanic, Asian) with 2 or more cases of breast and/or ovarian cancer among first- and second-degree relatives. Families were identified at US sites between February 1992 and May 2003; in each family, the individual with the highest probability of being a mutation carrier was tested. Main Outcome Measures  Frequency of BRCA1 and BRCA2 mutations and area under the receiver operating characteristic curve for the BRCAPRO model. Results  The mutation spectrum was vastly different between families of African and European ancestry. Compared with non-Hispanic, non-Jewish whites, African Americans had a lower rate of deleterious BRCA1 and BRCA2 mutations but a higher rate of sequence variations (27.9% vs 46.2% and 44.2% vs 11.5%; P<.001 for overall comparison). Deleterious mutations in BRCA1 and BRCA2 were highest for Ashkenazi Jewish families (69.0%). Early age at diagnosis of breast cancer and number of first- and second-degree relatives with breast and ovarian cancer were significantly associated with an increased likelihood of carrying a BRCA1 or BRCA2 mutation. In discriminating between mutation carriers, BRCAPRO performed as well in African American families as it did in white and Jewish families, with an area under the curve of 0.77 (95% confidence interval, 0.61-0.88) for African American families and 0.70 (95% confidence interval, 0.60-0.79) for white and Jewish families combined. Conclusions  These data support the use of BRCAPRO and genetic testing for BRCA1 and BRCA2 mutations in the management of high-risk African American families. Irrespective of ancestry, early age at diagnosis and a family history of breast and ovarian cancer are the most powerful predictors of mutation status and should be used to guide clinical decision making.      

Limited family structure and BRCA gene mutation status in single cases of breast cancer

Context  An autosomal dominant pattern of hereditary breast cancer may be masked by small family size or transmission through males given sex-limited expression. Objective  To determine if BRCA gene mutations are more prevalent among single cases of early onset breast cancer in families with limited vs adequate family structure than would be predicted by currently available probability models. Design, Setting, and Participants  A total of 1543 women seen at US high-risk clinics for genetic cancer risk assessment and BRCA gene testing were enrolled in a prospective registry study between April 1997 and February 2007. Three hundred six of these women had breast cancer before age 50 years and no first- or second-degree relatives with breast or ovarian cancers. Main Outcome Measure  The main outcome measure was whether family structure, assessed from multigenerational pedigrees, predicts BRCA gene mutation status. Limited family structure was defined as fewer than 2 first- or second-degree female relatives surviving beyond age 45 years in either lineage. Family structure effect and mutation probability by the Couch, Myriad, and BRCAPRO models were assessed with stepwise multiple logistic regression. Model sensitivity and specificity were determined and receiver operating characteristic curves were generated. Results  Family structure was limited in 153 cases (50%). BRCA gene mutations were detected in 13.7% of participants with limited vs 5.2% with adequate family structure. Family structure was a significant predictor of mutation status (odds ratio, 2.8; 95% confidence interval, 1.19-6.73; P = .02). Although none of the models performed well, receiver operating characteristic analysis indicated that modification of BRCAPRO output by a corrective probability index accounting for family structure was the most accurate BRCA gene mutation status predictor (area under the curve, 0.72; 95% confidence interval, 0.63-0.81; P<.001) for single cases of breast cancer. Conclusions  Family structure can affect the accuracy of mutation probability models. Genetic testing guidelines may need to be more inclusive for single cases of breast cancer when the family structure is limited and probability models need to be recreated using limited family history as an actual variable.      

Founder and recurrent CDH1 mutations in families with hereditary diffuse gastric cancer

Context  Hereditary diffuse gastric cancer is caused by germline mutations in the epithelial cadherin (CDH1) gene and is characterized by an increased risk for diffuse gastric cancer and lobular breast cancer. Objective  To determine whether recurring germline CDH1 mutations occurred due to independent mutational events or common ancestry. Design, Setting, and Patients  Thirty-eight families diagnosed clinically with hereditary diffuse gastric cancer were accrued between November 2004 and January 2006 and were analyzed for CDH1 mutations as part of an ongoing study at the British Columbia Cancer Agency. Twenty-six families had at least 2 gastric cancer cases with 1 case of diffuse gastric cancer in a person younger than 50 years; 12 families had either a single case of diffuse gastric cancer diagnosed in a person younger than 35 years or multiple cases of diffuse gastric cancer diagnosed in persons older than 50 years. Main Outcome Measures  Classification of family members as carriers or noncarriers of CDH1 mutations. Haplotype analysis to assess recurring mutations for common ancestry was performed on 7 families from this study and 7 previously reported families with the same mutations. Results  Thirteen mutations (6 novel) were identified in 15 of the 38 families (40% detection rate). The 1137G>A splicing mutation and the 1901C>T (A634V) missense/splicing mutation occurred on common haplotypes in 2 families but on different haplotypes in a third family. The 2195G>A (R732Q) missense/splicing mutation occurred in 2 families on different haplotypes. The 2064-2065delTG mutation occurred on a common haplotype in 2 families. Two families from this study plus 2 additional families carrying the novel 2398delC mutation shared a common haplotype, suggesting a founder effect. All 4 families originate from the southeast coast of Newfoundland. Due to concentrations of lobular breast cancer cases, 2 branches of this family had been diagnosed as having hereditary breast cancer and were tested for BRCA mutations. Within these 4 families, the cumulative risk by age 75 years in mutation carriers for clinically detected gastric cancer was 40% (95% confidence interval [CI], 12%-91%) for males and 63% (95% CI, 19%-99%) for females and the risk for breast cancer in female mutation carriers was 52% (95% CI, 29%-94%). Conclusions  Recurrent CDH1 mutations in families with hereditary diffuse gastric cancer are due to both independent mutational events and common ancestry. The presence of a founder mutation from Newfoundland is strongly supported.      

Surveillance of BRCA1 and BRCA2 mutation carriers with magnetic resonance imaging, ultrasound, mammography, and clinical breast examination

Context  Current recommendations for women who have a BRCA1 or BRCA2 mutation are to undergo breast surveillance from age 25 years onward with mammography annually and clinical breast examination (CBE) every 6 months; however, many tumors are detected at a relatively advanced stage. Magnetic resonance imaging (MRI) and ultrasound may improve the ability to detect breast cancer at an early stage. Objective  To compare the sensitivity and specificity of 4 methods of breast cancer surveillance (mammography, ultrasound, MRI, and CBE) in women with hereditary susceptibility to breast cancer due to a BRCA1 or BRCA2 mutation. Design, Setting, and Participants  A surveillance study of 236 Canadian women aged 25 to 65 years with BRCA1 or BRCA2 mutations who underwent 1 to 3 annual screening examinations, consisting of MRI, mammography, and ultrasound at a single tertiary care teaching hospital between November 3, 1997, and March 31, 2003. On the day of imaging and at 6-month intervals, CBE was performed. Main Outcome Measures  Sensitivity and specificity of each of the 4 surveillance modalities, and sensitivity of all 4 screening modalities vs mammography and CBE. Results  Each imaging modality was read independently by a radiologist and scored on a 5-point Breast Imaging Reporting and Data System scale. All lesions with a score of 4 or 5 (suspicious or highly suspicious for malignancy) were biopsied. There were 22 cancers detected (16 invasive and 6 ductal carcinoma in situ). Of these, 17 (77%) were detected by MRI vs 8 (36%) by mammography, 7 (33%) by ultrasound, and 2 (9.1%) by CBE. The sensitivity and specificity (based on biopsy rates) were 77% and 95.4% for MRI, 36% and 99.8% for mammography, 33% and 96% for ultrasound, and 9.1% and 99.3% for CBE, respectively. There was 1 interval cancer. All 4 screening modalities combined had a sensitivity of 95% vs 45% for mammography and CBE combined. Conclusions  In BRCA1 and BRCA2 mutation carriers, MRI is more sensitive for detecting breast cancers than mammography, ultrasound, or CBE alone. Whether surveillance regimens that include MRI will reduce mortality from breast cancer in high-risk women requires further investigation.      

Racial differences in the use of BRCA1/2 testing among women with a family history of breast or ovarian cancer

Context  Given the current context of racial disparities in health and health care and the historical context of eugenics, racial disparities in the use of genetic susceptibility testing have been widely anticipated. However, to our knowledge there are no published studies examining the magnitude and determinants of racial differences in the use of genetic susceptibility testing. Objectives  To investigate the relationship between race and the use of BRCA1/2 counseling among women with a family history of breast or ovarian cancer and to determine the contribution of socioeconomic characteristics, cancer risk perception and worry, attitudes about genetic testing, and interactions with primary care physicians to racial differences in utilization. Design, Setting, and Participants  Case-control study (December 1999-August 2003) of 408 women with a family history of breast or ovarian cancer, of whom 217 underwent genetic counseling for BRCA1/2 testing (cases) and 191 women did not (controls). Participants received primary care within a large health system in greater Philadelphia, Pa. Main Outcome Measures  Probability of carrying a BRCA1/2 mutation, socioeconomic characteristics, perception of breast and ovarian cancer risk, worry about breast and ovarian cancer, attitudes about BRCA1/2 testing, and primary care physician discussion of BRCA1/2 testing were measured prior to undergoing BRCA1/2 counseling for cases and at the time of enrollment for controls. Results  African American women with a family history of breast or ovarian cancer were significantly less likely to undergo genetic counseling for BRCA1/2 testing than were white women with a family history of breast or ovarian cancer (odds ratio, 0.22; 95% confidence interval, 0.12-0.40). This association persisted after adjustment for probability of BRCA1/2 mutation, socioeconomic characteristics, breast and ovarian cancer risk perception and worry, attitudes about the risks and benefits of BRCA1/2 testing, and primary care physician discussion of BRCA1/2 testing (adjusted odds ratio for African American vs white, 0.28; 95% confidence interval, 0.09-0.89). Conclusions  Racial disparities in the use of BRCA1/2 counseling are large and do not appear to be explained by differences in risk factors for carrying a BRCA1/2 mutation, socioeconomic factors, risk perception, attitudes, or primary care physician recommendations. The benefit of predictive genetic testing will not be fully realized unless these disparities can be addressed.      

Breast cancer following radiotherapy and chemotherapy among young women with Hodgkin disease

Context  Second cancer is the leading cause of death in long-term survivors of Hodgkin disease (HD), with exceptionally high risks of breast cancer among women treated at a young age. Quantitative associations between radiotherapy dose delivered to the breast and administered chemotherapy have not been reported to date in large series, nor has the influence of ovarian exposures on subsequent risk. Objective  To quantify the long-term risk of breast cancer associated with use of radiotherapy and chemotherapy to treat young women with HD. Design, Setting, and Subjects  Matched case-control study of breast cancer within a cohort of 3817 female 1-year survivors of HD diagnosed at age 30 years or younger, between January 1, 1965, and December 31, 1994, and within 6 population-based cancer registries. The study was conducted March 1, 1996, through September 30, 1998. Main Outcome Measures  Relative risk (RR) of breast cancer associated with radiation dose delivered to site of breast cancer or to ovaries and with cumulative dose of alkylating agents. Results  Breast cancer occurred in 105 patients with HD who were matched to 266 patients with HD but without breast cancer. A radiation dose of 4 Gy or more delivered to the breast was associated with a 3.2-fold (95% confidence interval [CI], 1.4-8.2) increased risk, compared with the risk in patients who received lower doses and no alkylating agents. Risk increased to 8-fold (95% CI, 2.6-26.4) with a dose of more than 40 Gy (P<.001 for trend). Radiation risk did not vary appreciably by age at exposure or reproductive history. Increased risks persisted for 25 or more years following radiotherapy (RR, 2.3; 95% CI, 0.5-16.5; P = .03 for trend with dose). Treatment with alkylating agents alone resulted in a reduced risk (RR, 0.6; 95% CI, 0.2-2.0) of breast cancer, and combined alkylating agents and radiotherapy in a 1.4-fold (95% CI, 0.6-3.5) increased risk. Risk of breast cancer decreased with increasing number of alkylating agent cycles (P = .003 for trend). Risk also was low (RR, 0.4; 95% CI, 0.1-1.1) among women who received 5 Gy or more delivered to ovaries compared with those who received lower doses. Conclusions  Hormonal stimulation appears important for the development of radiation-induced breast cancer, as evidenced by the reduced risk associated with ovarian damage from alkylating agents or radiation. The high radiation-related risk, which did not diminish at the highest doses or the longest follow-up, however, suggests the need for lifetime surveillance and programs of patient and public awareness.      

Cost-effectiveness of screening BRCA1/2 mutation carriers with breast magnetic resonance imaging

Context  Women with inherited BRCA1/2 mutations are at high risk for breast cancer, which mammography often misses. Screening with contrast-enhanced breast magnetic resonance imaging (MRI) detects cancer earlier but increases costs and results in more false-positive scans. Objective  To evaluate the cost-effectiveness of screening BRCA1/2 mutation carriers with mammography plus breast MRI compared with mammography alone. Design, Setting, and Patients  A computer model that simulates the life histories of individual BRCA1/2 mutation carriers, incorporating the effects of mammographic and MRI screening was used. The accuracy of mammography and breast MRI was estimated from published data in high-risk women. Breast cancer survival in the absence of screening was based on the Surveillance, Epidemiology and End Results database of breast cancer patients diagnosed in the prescreening period (1975-1981), adjusted for the current use of adjuvant therapy. Utilization rates and costs of diagnostic and treatment interventions were based on a combination of published literature and Medicare payments for 2005. Main Outcome Measures  The survival benefit, incremental costs, and cost-effectiveness of MRI screening strategies, which varied by ages of starting and stopping MRI screening, were computed separately for BRCA1 and BRCA2 mutation carriers. Results  Screening strategies that incorporate annual MRI as well as annual mammography have a cost per quality-adjusted life-year (QALY) gained ranging from less than $45 000 to more than $700 000, depending on the ages selected for MRI screening and the specific BRCA mutation. Relative to screening with mammography alone, the cost per QALY gained by adding MRI from ages 35 to 54 years is $55 420 for BRCA1 mutation carriers, $130 695 for BRCA2 mutation carriers, and $98 454 for BRCA2 mutation carriers who have mammographically dense breasts. Conclusions  Breast MRI screening is more cost-effective for BRCA1 than BRCA2 mutation carriers. The cost-effectiveness of adding MRI to mammography varies greatly by age.      

Salpingo-oophorectomy and the risk of ovarian, fallopian tube, and peritoneal cancers in women with a BRCA1 or BRCA2 Mutation

Context  Women with BRCA1 or BRCA2 mutation are often advised to undergo preventive oophorectomy. The effectiveness of this intervention has not been prospectively evaluated in a large cohort. Objectives  To estimate the incidence of ovarian, fallopian tube, and primary peritoneal cancer in women who carry a deleterious mutation in BRCA1 or BRCA2. To estimate the reduction in risk of these cancers associated with a bilateral prophylactic salpingo-oophorectomy. Design, Setting, and Participants  Women known to carry a BRCA1 or BRCA2 mutation were identified from an international registry between 1992 and 2003. A total of 1828 carriers at 1 of 32 centers in Canada, the United States, Europe, and Israel completed questionnaires at baseline and follow-up. Participants were observed from the date of study entry until: diagnosis of ovarian, fallopian tube, or peritoneal cancer; death; or the date of the most recent follow-up. Intervention  Participants were divided into women who had undergone bilateral prophylactic oophorectomy and those who had not. Main Outcome Measure  The incidence of ovarian, peritoneal, and fallopian tube cancer was determined by survival analysis. The risk reduction associated with prophylactic salpingo-oophorectomy was evaluated by a time-dependent survival analysis, adjusting for covariates. Results  After a mean follow-up of 3.5 years, 50 incident ovarian, fallopian tube, and peritoneal cancer cases were reported in the cohort. Of the 1828 women, 555 (30%) underwent a bilateral prophylactic salpingo-oophorectomy prior to study entry, 490 (27%) underwent the procedure after entering the study, and 783 (43%) did not undergo the procedure. There were 32 incident cancers diagnosed in women with intact ovaries (1015/100 000 per year). Eleven cancer cases were identified at the time of prophylactic oophorectomy and 7 were diagnosed following prophylactic oophorectomy (217/100 000 per year). The estimated cumulative incidence of peritoneal cancer is 4.3% at 20 years after oophorectomy. The overall (adjusted) reduction in cancer risk associated with bilateral oophorectomy is 80% (multivariate hazard ratio = 0.20; 95% confidence interval, 0.07-0.58; P = .003). Conclusion  Oophorectomy is associated with reduced risk of ovarian and fallopian tube cancer in high-risk women, although there is a substantial residual risk for peritoneal cancer in BRCA1 and BRCA2 mutation carriers following prophylactic salpingo-oophorectomy.      

Effect of a computer-based decision aid on knowledge, perceptions, and intentions about genetic testing for breast cancer susceptibility: a randomized controlled trial

Context  As the availability of and demand for genetic testing for hereditary cancers increases in primary care and other clinical settings, alternative or adjunct educational methods to traditional genetic counseling will be needed. Objective  To compare the effectiveness of a computer-based decision aid with standard genetic counseling for educating women about BRCA1 and BRCA2 genetic testing. Design  Randomized controlled trial conducted from May 2000 to September 2002. Setting and Participants  Outpatient clinics offering cancer genetic counseling at 6 US medical centers enrolled 211 women with personal or family histories of breast cancer. Interventions  Standard one-on-one genetic counseling (n = 105) or education by a computer program followed by genetic counseling (n = 106). Main Outcome Measures  Participants' knowledge, risk perception, intention to undergo genetic testing, decisional conflict, satisfaction with decision, anxiety, and satisfaction with the intervention. Counselor group measures were administered at baseline and after counseling. Computer group measures were administered at baseline, after computer use, and after counseling. Testing decisions were assessed at 1 and 6 months. Outcomes were analyzed by high vs low risk of carrying a BRCA1 or BRCA2 mutation. Results  Both groups had comparable demographics, prior computer experience, medical literacy, and baseline knowledge of breast cancer and genetic testing, and both counseling and computer use were rated highly. Knowledge scores increased in both groups (P<.001) regardless of risk status, and change in knowledge was greater in the computer group compared with the counselor group (P = .03) among women at low risk of carrying a mutation. Perception of absolute risk of breast cancer decreased significantly after either intervention among all participants. Intention to undergo testing decreased significantly after either intervention among low-risk but not high-risk women. The counselor group had lower mean scores on a decisional conflict scale (P = .04) and, in low-risk women, higher mean scores on a satisfaction-with-decision scale (P = .001). Mean state anxiety scores were reduced by counseling but were within normal ranges for both groups at baseline and after either intervention, regardless of risk status. Conclusions  An interactive computer program was more effective than standard genetic counseling for increasing knowledge of breast cancer and genetic testing among women at low risk of carrying a BRCA1 or BRCA2 mutation. However, genetic counseling was more effective than the computer at reducing women's anxiety and facilitating more accurate risk perceptions. These results suggest that this computer program has the potential to stand alone as an educational intervention for low-risk women but should be used as a supplement to genetic counseling for those at high risk.      

Adult weight change and risk of postmenopausal breast cancer

Context  Endogenous hormones are a primary cause of breast cancer. Adiposity affects circulating hormones, particularly in postmenopausal women, and may be a modifiable risk factor for breast cancer. Objective  To assess the associations of adult weight change since age 18 years and since menopause with the risk of breast cancer among postmenopausal women. Design, Setting, and Participants  Prospective cohort study within the Nurses' Health Study. A total of 87 143 postmenopausal women, aged 30 to 55 years and free of cancer, were followed up for up to 26 years (1976-2002) to assess weight change since age 18 years. Weight change since menopause was assessed among 49 514 women who were followed up for up to 24 years. Main Outcome Measure  Incidence of invasive breast cancer. Results  Overall, 4393 cases of invasive breast cancer were documented. Compared with those who maintained weight, women who gained 25.0 kg or more since age 18 years were at an increased risk of breast cancer (relative risk [RR], 1.45; 95% confidence interval [CI], 1.27-1.66; P<.001 for trend), with a stronger association among women who have never taken postmenopausal hormones (RR,1.98; 95% CI, 1.55-2.53). Compared with weight maintenance, women who gained 10.0 kg or more since menopause were at an increased risk of breast cancer (RR, 1.18; 95% CI, 1.03-1.35; P  = .002 for trend). Women who had never used postmenopausal hormones, lost 10.0 kg or more since menopause, and kept the weight off were at a lower risk than those who maintained weight (RR, 0.43; 95% CI, 0.21-0.86; P = .01 for weight loss trend). Overall, 15.0% (95% CI, 12.8%-17.4%) of breast cancer cases in this population may be attributable to weight gain of 2.0 kg or more since age 18 years and 4.4% (95% CI, 3.6%-5.5%) attributable to weight gain of 2.0 kg or more since menopause. Among those who did not use postmenopausal hormones, the population attributable risks are 24.2% (95% CI, 19.8%-29.1%) for a weight gain since age 18 years and 7.6% (95% CI, 5.9%-9.7%) for weight gain since menopause. Conclusions  These data suggest that weight gain during adult life, specifically since menopause, increases the risk of breast cancer among postmenopausal women, whereas weight loss after menopause is associated with a decreased risk of breast cancer. Thus, in addition to other known benefits of healthy weight, our results provide another reason for women approaching menopause to maintain or lose weight, as appropriate.      

Frequency of Breast Cancer Attributable to BRCA1 in a Population-Based Series of American Women

Context.— Previous studies of BRCA1 mutation prevalence have been based on high-risk groups, yielding estimates that do not reflect the experience of the general population of US patients with breast cancer. Objective.— To determine prevalence of known disease-related mutations and other variants in BRCA1 and how it differs by race, age at diagnosis, and family history status in a population-based sample of white and black patients with breast cancer unselected for family history. Design.— Case-control study. Setting.— A 24-county area of central and eastern North Carolina. Participants.— Cases were women aged 20 to 74 years diagnosed as having a first invasive breast cancer between May 1993 and June 1996. Controls were frequency matched to cases by 5-year age range and race. The first 211 cases and 188 controls regardless of race and the subsequent 99 cases and 108 controls of African American ancestry are included in this report. Main Outcome Measure.— Germline variants at any site in the coding sequence, splice junctions, 5' untranslated region, or 3' untranslated region of the BRCA1 gene were analyzed in cases, and selected variants were analyzed in controls. Screening was performed using multiplex single-strand conformation analysis, with all potential variants confirmed using genomic sequencing. Results.— Three of 211 patients with breast cancer had disease-related variants at BRCA1, all of which were protein-truncating mutations. After adjustment for sampling probabilities, the proportion of patients with breast cancer with disease-related variants was 3.3% (95% confidence interval, 0%-7.2%) in white women and 0% in black women. Young age at diagnosis alone did not predict BRCA1 carrier status in this population. In white women, prevalence of inherited mutation was 23% for cases with family history of ovarian cancer, 13% for cases from families with at least 4 cases of breast cancer with or without ovarian cancer, and 33% for cases from families with both breast and ovarian cancer and at least 4 affected relatives. Because these results are based on few families at the highest levels of risk, confidence intervals around these estimates are wide. An additional 5 patients had rare missense mutations or a single amino acid deletion, the biological significance of which is unknown. In black women, a variant in the 3' untranslated region was statistically significantly more common in cases than in controls. Conclusions.— These data suggest that in the general US population, widespread screening of BRCA1 is not warranted. In contrast, BRCA1 mutations are sufficiently frequent in families with both breast and ovarian cancer, or at least 4 cases of breast cancer (at any age), that genotyping might be considered. The emerging picture of BRCA1 population genetics involves complex interactions of family history, age, and genetic ancestry, all of which should be taken into account when considering testing or interpreting results.      

Somatic acquisition and signaling of TGFBR1*6A in cancer

Context  TGFBR1*6A is a common polymorphism of the type I transforming growth factor receptor (TGFBR1). Epidemiological studies suggest that TGFBR1*6A may act as a tumor susceptibility allele. How TGFBR1*6A contributes to cancer development is largely unknown. Objectives  To determine whether TGFBR1*6A is somatically acquired by primary tumors and metastases during cancer development and whether the 3–amino acid deletion that differentiates TGFBR1*6A from TGFBR1 is part of the mature receptor or part of the signal sequence and to investigate TGFBR1*6A signaling in cancer cells. Design, Setting, and Patients  Tumor and germline tissues from 531 patients with a diagnosis of head and neck, colorectal, or breast cancer recruited from 3 centers in the United States and from 1 center in Spain from June 1, 1994, through June 30, 2004. In vitro translation assays, MCF-7 breast cancer cells stably transfected with TGFBR1*6A, TGFBR1, or the vector alone, DLD-1 colorectal cancer cells that endogenously carry TGFBR1*6A, and SW48 colorectal cancer cells that do not carry TGFBR1*6A. Main Outcome Measures  TGFBR1*6A somatic acquisition in cancer. Determination of the amino terminus of the mature TGFBR1*6A and TGFBR1 receptors. Determination of TGF-–dependent cell proliferation. Results  TGFBR1*6A was somatically acquired in 13 of 44 (29.5%) colorectal cancer metastases, in 4 of 157 (2.5%) of colorectal tumors, in 4 of 226 (1.8%) head and neck primary tumors, and in none of the 104 patients with breast cancer. TGFBR1*6A somatic acquisition is not associated with loss of heterozygosity, microsatellite instability, or a mutator phenotype. The signal sequences of TGFBR1 and TGFBR1*6A are cleaved at the same site resulting in identical mature receptors. TGFBR1*6A may switch TGF- growth inhibitory signals into growth stimulatory signals in MCF-7 breast cancer cells and in DLD-1 colorectal cancer cells. Conclusions  TGFBR1*6A is somatically acquired in 29.5% of liver metastases from colorectal cancer and may bestow cancer cells with a growth advantage in the presence of TGF-. The functional consequences of this conversion appear to be mediated by the TGFBR1*6A signal sequence rather than by the mature receptor. The results highlight a new facet of TGF- signaling in cancer and suggest that TGFBR1*6A may represent a potential therapeutic target in cancer.      

Holidays, birthdays, and postponement of cancer death

Context  Articles in the medical literature and lay press have supported a belief that individuals, including those dying of cancer, can temporarily postpone their death to survive a major holiday or other significant event, but results and effects have been variable. Objective  To determine whether, for the patient dying of cancer, a "death takes a holiday" effect showing a reduction in deaths in the week before a significant event was associated with Christmas, the US holiday of Thanksgiving, or the date of the individual’s birthday. Design, Setting, and Subjects  Analysis of death certificate data for all 1 269 474 persons dying in Ohio from 1989-2000, including 309 221 persons dying with cancer noted as the leading cause of death. Main Outcome Measure  We measured the total number of cancer deaths in the 2 weeks centered on the event of interest and the proportion of these deaths that occurred in the week before the event to determine whether this proportion was significantly different from 0.5 by using an exact binomial test. Results  The proportion of persons dying of cancer in the week before Christmas, Thanksgiving, and the individual’s birthday was not significantly different from the proportion dying in the week after the event (P = .52, .26, and .06, respectively). However, among black individuals there was an increase in cancer deaths in the week before Thanksgiving (P = .01), whereas women showed an increase in cancer deaths in the week before their birthday (P = .05). There was no statistically significant excess of deaths in the postevent week in any subgroup. Conclusion  We found no evidence, in contrast to previous studies, that cancer patients are able to postpone their deaths to survive significant religious, social, or personal events.      

Accuracy of revised Bethesda guidelines, microsatellite instability, and immunohistochemistry for the identification of patients with hereditary nonpolyposis colorectal cancer

Context  The selection of individuals for hereditary nonpolyposis colorectal cancer (HNPCC) genetic testing is challenging. Recently, the National Cancer Institute outlined a new set of recommendations, the revised Bethesda guidelines, for the identification of individuals with HNPCC who should be tested for microsatellite instability. Objective  To establish the most effective and efficient strategy for the detection of MSH2/MLH1 gene carriers. Design, Setting, and Patients  A prospective, multicenter, nationwide study (the EPICOLON study) in 20 hospitals in the general community in Spain of 1222 patients with newly diagnosed colorectal cancer between November 1, 2000, and October 31, 2001. Interventions  Microsatellite instability testing and MSH2/MLH1 immunostaining in all patients regardless of age, personal or family history, and tumor characteristics. Patients whose tumors exhibited microsatellite instability and/or lack of protein expression underwent MSH2/MLH1 germline testing. Main Outcome Measures  Effectiveness and efficiency of both microsatellite instability testing and immunostaining, either directly or previous selection of patients according to the revised Bethesda guidelines, were evaluated with respect to the presence of MSH2/MLH1 germline mutations. Results  Two hundred eighty-seven patients (23.5%) fulfilled the revised Bethesda guidelines. Ninety-one patients (7.4%) had a mismatch repair deficiency, with tumors exhibiting either microsatellite instability (n = 83) or loss of protein expression (n = 81). Germline testing identified 11 mutations (0.9%) in either MSH2 (7 cases) or MLH1 (4 cases) genes. Strategies based on either microsatellite instability testing or immunostaining previous selection of patients according to the revised Bethesda guidelines were the most effective (sensitivity, 81.8% and 81.8%; specificity, 98.0% and 98.2%; positive predictive value, 27.3% and 29.0%, respectively) to identify MSH2/MLH1 gene carriers. Logistic regression analysis confirmed the revised Bethesda guidelines as the most discriminating set of clinical parameters (odds ratio, 33.3; 95% confidence interval, 4.3-250; P = .001). Conclusion  The revised Bethesda guidelines constitute a useful approach to identify patients at risk for HNPCC. In patients fulfilling these criteria, both microsatellite instability testing and immunostaining are equivalent and highly effective strategies to further select those patients who should be tested for MSH2/MLH1 germline mutations.      

Recreational physical activity and the risk of breast cancer in postmenopausal women: the Women's Health Initiative Cohort Study

Context  Women who are physically active have a decreased risk for breast cancer, but the types, amounts, and timing of activity needed are unknown. Objective  To prospectively examine the association between current and past recreational physical activity and incidence of breast cancer in postmenopausal women. Design, Setting, and Patients  Prospective cohort study in 74 171 women aged 50 to 79 years who were recruited by 40 US clinical centers from 1993 through 1998. Main Outcome Measure  Incident invasive and in situ breast cancer. Results  We documented 1780 newly diagnosed cases of breast cancer over a mean follow-up of 4.7 years. Compared with less active women, women who engaged in regular strenuous physical activity at age 35 years had a 14% decreased risk of breast cancer (relative risk [RR], 0.86; 95% confidence interval [CI], 0.78-0.95). Similar but attenuated findings were observed for strenuous physical activity at ages 18 years and 50 years. An increasing total current physical activity score was associated with a reduced risk for breast cancer (P = .03 for trend). Women who engaged in the equivalent of 1.25 to 2.5 hours per week of brisk walking had an 18% decreased risk of breast cancer (RR, 0.82; 95% CI, 0.68-0.97) compared with inactive women. Slightly greater reduction in risk was observed for women who engaged in the equivalent of 10 hours or more per week of brisk walking. The effect of exercise was most pronounced in women in the lowest tertile of body mass index (BMI) (<24.1), but also was observed for women in the middle tertile of BMI (24.1-28.4). Conclusions  These data suggest that increased physical activity is associated with reduced risk for breast cancer in postmenopausal women, longer duration provides most benefit, and that such activity need not be strenuous.      

Frequency of germline genomic homozygosity associated with cancer cases

Guillaume Assié, MD, PhD; Thomas LaFramboise, PhD; Petra Platzer, PhD; Charis Eng, MD, PhD

JAMA. 2008;299(12):1437-1445.

Context  Cancer is a multigenic disease resulting from both germline susceptibility and somatic events. While studying loss of heterozygosity (LOH) in cancer tissues, we anecdotally observed a low frequency of heterozygosity in cancer patients compared with controls, raising the question whether homozygosity could play a role in cancer predisposition.

Objectives  To determine the frequency of germline homozygosity in a large series of patients with 3 different types of solid tumors compared with population-based controls.

Design, Setting, and Patients  Germline and corresponding tumor DNA isolated from 385 patients with carcinomas (147 breast, 116 prostate, and 122 head and neck carcinomas) were subjected to whole genome (345-microsatellite marker) LOH analysis.

Main Outcome Measures  Frequency of homozygosity at microsatellite markers in cancer cases vs controls and frequency of somatic LOH in cancers at loci with the highest homozygosity.

Results  We identified 16 loci in common among the 3 cancer types, with significantly increased germline homozygosity frequencies in the cancer patients compared with controls (P < .001). In the cases who happened to be germline heterozygous at these 16 loci, we found a mean (SD) LOH frequency of 58% (4.2%) compared with 50% (7.5%) at 197 markers without increased germline homozygosity (P < .001). Across the genome, this relationship holds as well (r = 0.46; 95% confidence interval, 0.37-0.53; P < .001). We validated the association of specific loci with high germline homozygosity frequencies in an independent, single-nucleotide polymorphism–based, public data set of 205 lung carcinomas from white individuals (P < .05 to P < .001) as well as the correlation between genome-wide germline homozygosity and LOH frequencies (r = 0.21; 95% confidence interval, 0.18-0.24; P < .001).

Conclusions  In our study of 4 different types of solid tumors (our data for 3 types validated in a fourth type), increased germline homozygosity occurred at specific loci. When the germline was heterozygous at these loci, high frequencies of LOH/allelic imbalance occurred at these loci in the corresponding carcinomas.