Risk of developing ovarian cancer among women with ovarian endometrioma: a cohort study in Shizuoka, Japan

Although some studies have indicated that endometriosis may increase the risk of developing ovarian cancer, there are no data from epidemiologic studies in Japan. We prospectively analyzed all cases of ovarian endometrioma enrolled in the prefecture-wide Shizuoka Cohort Study on Endometriosis and Ovarian Cancer Programme, which was initiated in 1985. To evaluate the risk of ovarian cancer by time periods subsequent to ovarian endometrioma diagnosis, a cohort of 6,398 women with a clinically documented ovarian endometrioma in Shizuoka between 1985 and 1995 was identified from the Shizuoka Cancer Registry (SCR), with follow-up through 2002. Ovarian cancer incidence among cohort members was ascertained by linkage to the SCR using a unique person-identification number. Standardized incidence ratios (SIR) and their 95% confidence intervals (CI) were computed by a use of prefecture-wide rates of ovarian cancer, adjusted for age and calendar year. During follow-up of up to 17 years of the ovarian endometrioma cohort, 46 incident ovarian cancers were identified, yielding that the ovarian cancer risk was elevated significantly among patients with ovarian endometrioma (SIR = 8.95, 95% CI = 4.12-15.3). The SIR did not increase with increasing follow-up duration. The risk increased with increasing age at ovarian endometrioma diagnosis, with a SIR equal to 13.2 (95% CI = 6.90-20.9) in women above 50 years of age. Our findings for the first time support the hypothesis that ovarian endometrioma increases the subsequent risk of developing ovarian cancer in Shizuoka, Japan.     

Cancer risk after hospital discharge diagnosis of benign ovarian cysts and endometriosis

BACKGROUND: The aim was to evaluate whether patients with benign ovarian cysts, functional ovarian cysts, or endometriosis have an increased risk of developing gynecologic cancer. METHODS: The Swedish Hospital Discharge Register was used to identify a cohort of women discharged from hospital with the diagnoses of ovarian cyst (n = 42217), functional ovarian cyst (n = 17998), or endometriosis (n = 28163). To each case, three controls were matched. The National Swedish Cancer Register matched all incident cancers diagnosed among cases and controls. From the Fertility Register, the date of birth of children born to the cases and controls were obtained. RESULTS: Women with endometriosis had an increased risk for ovarian cancer (OR 1.34; 95% CI 1.03-1.75), but no association was found between ovarian cysts or functional cysts and ovarian malignancy, including all ages. Young women (15-29 years old) discharged from hospital for ovarian cysts and functional cysts showed an increased risk of developing ovarian cancer later in life (OR 2.2; 95% CI 1.3-3.9 and OR 1.8; 95% CI 1.5-2.0), as well as women with ovarian cysts who had undergone ovarian cyst resection or unilateral oophorectomy (OR 8.8; 95% CI 5.2-15). The risk of developing ovarian cancer was inversely related to parity. Mean age at diagnosis was significantly lower in all three study groups. CONCLUSION: In this study women with endometriosis and young women who had undergone surgery with removal of an ovarian cyst had an increased risk of developing ovarian cancer.     

In vitro fertilization,endometriosis, nulliparity and ovarian cancer risk

ObjectivesTo examine the risk of invasive epithelial ovarian cancer in a cohort of women seeking treatment for infertility.MethodsUsing whole-population linked hospital and registry data, we conducted a cohort study of 21,646 women commencing hospital investigation and treatment for infertility in Western Australia in the years 1982–2002. We examined the effects of IVF treatment, endometriosis and parity on risk of ovarian cancer and explored potential confounding by tubal ligation, hysterectomy and unilateral oophorectomy/salpingo-oophorectomy (USO).ResultsParous women undergoing IVF had no observable increase in the rate of ovarian cancer (hazard ratio [HR] 1.01; 95% confidence interval [CI] 0.35–2.90); the HR in women who had IVF and remained nulliparous was 1.76 (95% CI 0.74–4.16). Women diagnosed with endometriosis who remained nulliparous had a three-fold increase in the rate of ovarian cancer (HR 3.11; 95% CI 1.13–8.57); the HR in parous women was 1.52 (95% CI 0.34–6.75). In separate analyses, women who had a USO without hysterectomy had a four-fold increase in the rate of ovarian cancer (HR 4.23; 95% CI 1.30–13.77). Hysterectomy with or without USO appeared protective.ConclusionsThere is no evidence of an increased risk of ovarian cancer following IVF in women who give birth. There is some uncertainty regarding the effect of IVF in women who remain nulliparous. Parous women diagnosed with endometriosis may have a slightly increased risk of ovarian cancer; nulliparous women have a marked increase in risk.     

In utero exposures and the incidence of endometriosis

OBJECTIVE: To investigate the relation between the fetal environment and endometriosis. DESIGN: Prospective cohort study. SETTING: Nurses' Health Study II with 10 years of follow-up. PARTICIPANT(S): Eighty-four thousand, four hundred forty-six women aged 25-42 who had never been diagnosed with endometriosis, infertility, or cancer at baseline in 1989. MAIN OUTCOME MEASURE(S): Incidence of laparoscopically confirmed endometriosis according to birthweight, prematurity, multiple gestation, diethylstilbestrol (DES) exposure, and having been breastfed. RESULT(S): During 566,250 woman-years of follow-up, 1,226 cases of laparoscopically-confirmed endometriosis were reported among women with no past infertility. After adjusting for age, calendar time, parity, race, and body mass index at age 18, we observed a linear increase in the incidence rate with decreasing birthweight (rate ratio [RR] = 1.3 for birthweight <5.5 pounds versus 7.0-8.4 pounds, 95% confidence interval [CI] = 1.0-1.8, P value, test for trend = .01). In addition, women who were born as one of a multiple gestation (i.e., twins or greater number) were at increased risk even after controlling for birthweight (RR = 1.7, CI = 1.2-2.5). The rate of endometriosis was also 80% greater among women exposed to diethylstilbestrol in utero (RR = 1.8, CI = 1.2-2.8). Neither premature delivery nor having been breastfed were associated with the incidence of endometriosis. None of these effect estimates were modified by infertility status at the time of endometriosis diagnosis. CONCLUSION(S): The fetal environment is associated with subsequent laparoscopically confirmed endometriosis in this cohort of US women.     

Are infertility treatments a potential risk factor for cancer development? Perspective of 30 years of follow-up

The aim of the present study was to evaluate the possible risk for cancer development in infertile women with over 30 years of follow-up. Cancer development was assessed through linkage with the National Cancer Registry updated to 31 December 2005 in a cohort of 2431 women who were treated for infertility at the Sheba Medical Center in Israel during the period 1964–1974 and contributed more than 84,000 women years of follow-up. Standardized incidence ratios (SIR) were calculated between the observed cancer cases and the expected cancer rates in the general population. The mean age at the end of follow-up was 62.7 years. Eighteen cases of ovarian cancer were observed as compared to 18.1 expected (SIR = 1.0; 95% CI = 0.59–1.57). For breast cancer, 153 cases were observed as compared to 131.9 expected (SIR = 1.16; 95% CI = 0.98–1.36), and for endometrial cancer, 30 cases were observed as compared to 17.8 expected cases (SIR = 1.69; 95% CI = 1.14–2.41). No excess risk associated with exposure to gonadotropins was observed. Infertility was found to be associated with significant increased risk for endometrial cancer and borderline increased risk for breast cancer. Ovarian cancer risk was not found to be elevated. No significant excess risk was associated with treatment with ovulation induction.     

Malignancies following in situ cervical cancer in Hispanic Americans and non-Hispanic Whites

OBJECTIVES: Some risk factors for cervical cancer in situ convey risk for malignancies of the cervix and other sites. We estimate risk of several malignancies following in situ cancer of the cervix for Hispanic Americans and non-Hispanic Whites. METHODS: Using California Cancer Registry data (1988-1999) we identify 56,020 women with cervical cancer in situ and observe subsequent malignancies in that cohort, with over three million woman-months of follow-up. We focus on cancers of the reproductive system and cancers related to smoking. Risk estimates are standardized incidence ratios, accounting for age, time at risk, cancer type, and race/ethnicity. RESULTS: There is elevated risk for invasive cervical cancer (SIR=4.1, 95% CI: 3.5-4.7), which is significantly higher for Hispanics than for non-Hispanic Whites (SIRs=5.2 and 3.2, respectively, chi2(1)=7.66, P=0.006). Excluding cervix, non-Hispanic Whites show elevated risk for a pool of reproductive cancers (SIR=1.8, 95% CI: 1.4-2.4). While both groups show elevated risk for a pool of smoking-related cancers, only non-Hispanic Whites show significant risk specifically for lung cancer (SIR=1.7, 95% CI: 1.4-2.1). Non-Hispanic Whites show elevated risk for ovarian cancer (SIR=1.8, 95% CI: 1.3-2.4). Ovarian cancer following in situ cervical cancer is disproportionately of borderline histology (G2(1)=7.43, P=0.006). CONCLUSIONS: These results have implications for public health planning for women, as well as better understanding of disparities in care or biologic paths to malignancies in women with in situ cancer of the cervix.     

Ovarian cancer risk after the use of ovulation-stimulating drugs

OBJECTIVE: To assess the long-term effects of ovulation-stimulating drugs on the risk of ovarian cancer. METHODS: A retrospective cohort study of 12,193 eligible study subjects (median age 30 years) who were evaluated for infertility during the period of 1965-1988 at 5 clinical sites identified 45 subsequent ovarian cancers in follow-up through 1999. Standardized incidence ratios compared the risk of cancer among the infertile patients to the general population, whereas analyses within the cohort allowed the derivation of rate ratios for drug usage compared with no usage after adjustment for other ovarian cancer predictors. RESULTS: The infertility patients had a significantly elevated ovarian cancer risk compared with the general population (standardized incidence ratio 1.98, 95% confidence intervals [CI] 1.4, 2.6). When patient characteristics were taken into account and risks assessed within the infertile women, the rate ratios associated with ever usage were 0.82 (95% CI 0.4, 1.5) for clomiphene and 1.09 (95% CI 0.4, 2.8) for gonadotropins. There were higher, albeit nonsignificant, risks with follow-up time, with the rate ratios after 15 or more years being 1.48 (95% CI 0.7, 3.2) for exposure to clomiphene (5 exposed cancer patients) and 2.46 (95% CI 0.7, 8.3) for gonadotropins (3 exposed cancer patients). Although drug effects did not vary by causes of infertility, there was a slightly higher risk associated with clomiphene use among women who remained nulligravid, based on 6 exposed patients (rate ratio 1.75; 95% CI 0.5, 5.7). CONCLUSION: The results of this study generally were reassuring in not confirming a strong link between ovulation-stimulating drugs and ovarian cancer. Slight but nonsignificant elevations in risk associated with drug usage among certain subgroups of users, however, support the need for continued monitoring of long-term risks. LEVEL OF EVIDENCE: II-2     

Assisted reproductive technology and the incidence of ovarian cancer: a meta-analysis

OBJECTIVE: To systematically evaluate the available literature regarding the relationship between assisted reproductive technology and ovarian cancer. DATA SOURCES: Computerized search of 6 databases from 1966 (or closest) to present: Cochrane Controlled Trials Register, Cancerlit, CINHAL, Current Contents, PubMed in process (formerly called PreMEDLINE), and MEDLINE. We collected references from the bibliographies of reviews, original research articles, content experts, and conference proceedings to find published and unpublished literature. METHODS OF STUDY SELECTION: Case-control and cohort studies are included. The population of interest is treated infertile women, the control population is untreated infertile women, and the intervention or exposure of interest includes the following fertility medications: clomiphene citrate, gonadotropins, human chorionic gonadotropin, and gonadotropin releasing hormone agonists. The primary outcome is incident, primary ovarian cancer. Three cohort and 7 case-control studies were included in the quantitative analyses. TABULATION, INTEGRATION, AND RESULTS: The Newcastle-Ottawa Quality Assessment Scales were used. Two investigators independently extracted study methods, sources of bias, and outcomes. The following information was recorded: publication information, subject characteristics, intervention information and outcomes. Studies combined were sufficiently homogeneous for quantitative summary. Case-control and cohort data showed a significantly elevated risk for exposure of infertility medications and ovarian cancer in subjects who underwent assisted reproductive technology compared with general population controls (1.52; 95% confidence interval [CI] 1.18 to 1.97). When cases of ovarian cancer were compared with infertile controls for exposure to infertility medications, the odds ratio (0.99; 95% CI 0.67, 1.45) was not elevated. However, cohort data comparing outcome in treated infertile patients with untreated infertile patients suggests that treated patients may tend to a lower incidence of ovarian cancer-odds ratio = 0.67 (95% CI 0.32, 1.41). CONCLUSION: Ovarian cancer does not appear to be increased in treated infertile patients versus untreated infertile patients. Treated infertile patients may have a lower incidence of ovarian cancer than untreated infertile patients.     

Oral contraceptive use and risk of endometriosis. Italian Endometriosis Study Group.

OBJECTIVE: To analyse the association between use of oral contraception and risk of pelvic endometriosis. DESIGN: We compared use of oral contraception in women with and without endometriosis. PARTICIPANTS: Eligible for the study were women with primary or secondary infertility (n = 393) or chronic pelvic pain (n = 424), requiring laparoscopy, consecutively observed between September 1995 and January 1996 in 15 obstetrics and gynaecology departments in Italy. RESULTS: Out of the 817 women included in the study, 345 had a diagnosis of endometriosis; 164 (47.5%) women with endometriosis and 139 (29.4%) without the disease reported ever using oral contraception. In comparison with never users the estimated odds ratios (OR) of endometriosis were 1.8 (95% CI 1.0-3.3) in current users and 1.6 (95% CI 1.1-2.4) in ex-users. No clear relation emerged between duration of oral contraceptive use and risk of endometriosis. In comparison with never users, the OR was 1.8 (95% CI 1.1-3.0) for women reporting their last use of oral contraception < 5 years before interview and 1.5 (95% CI 0.9-2.5) for those reporting their last use > or = 5 years before interview. CONCLUSIONS: The study suggests that oral contraception is associated with an increased risk of endometriosis but this finding is based on a selected population and cannot generalised to all women with endometriosis.     

Secondary malignant neoplasms in patients with breast cancer

OBJECTIVE: This report analyzes the occurrence of secondary malignancies among patients with breast cancer. MATERIAL AND METHODS: We evaluated all women diagnosed with breast cancer who were reported to the National Cancer Institute of the former GDR in 1976. There was a follow up of 5,485 patients from 1976 to 1988 (38,231 person-years at risk). Cancer incidence rates of the whole female population specific for age and calendar year were used for calculation of the standardized incidence ratio (SIR). RESULTS: Significantly increased risks were observed for neoplasms of the bilateral breast (SIR 2.44; 95% CI 2.04-2.93), colon (SIR 1.53; 95% CI 1.06-2.12), rectum (SIR 1.65; 95% CI 1.10-2.40), endometrium (SIR 1.55; 95% CI 1.02-2.27), and ovary (SIR 1.71; 95% CI 1.09-2.57). Neoplasms of the lung (SIR 1.65; 95% CI 0.93-2.73), kidney (SIR 1.51; 95% CI 0.69-2.87), bladder (SIR 1.32; 95% CI 0.48-2.87), connective tissue (SIR 3.54; 95% CI 0.73-10.34), and multiple myeloma (SIR 1.98; 95% CI 0.54-5.06) were also increased, not reaching statistical significance. Risk reduction was observed for malignant tumors of the gallbladder (SIR 0.36; 95% CI 0.12-0.83). CONCLUSION: In proposing recommendations for the follow-up and management of women with breast cancer, it is important to recognize their long-term predisposition to an array of secondary cancers.     

Oral contraceptive use, reproductive history, and risk of epithelial ovarian cancer in women with and without endometriosis

OBJECTIVE: Women with endometriosis may be at an increased risk of ovarian cancer. It is not known whether reproductive factors that reduce the risk of ovarian cancer in general also reduce risk in women with endometriosis. We investigated whether the odds ratios for ovarian cancer that were associated with oral contraceptive use, childbearing, hysterectomy, and tubal ligation differ among women with and without endometriosis. STUDY DESIGN: We pooled information on the self-reported history of endometriosis from 4 population-based case-controlled studies of incident epithelial ovarian cancer, comprising 2098 cases and 2953 control subjects. We obtained data on oral contraceptive use, childbearing, breastfeeding, gynecologic surgical procedures, and other reproductive factors on each woman. Multivariable unconditional logistic regression was used to calculate odds ratios and 95% CI for ovarian cancer among women with endometriosis compared with women without endometriosis. Similar methods were used to assess the frequencies of risk factors among women with and without endometriosis. Adjustments were made for age, parity, oral contraceptive use, tubal ligation, family history of ovarian cancer, and study site. RESULTS: Women with endometriosis were at an increased risk of ovarian cancer (odds ratio, 1.32; 95% CI, 1.06-1.65). Using oral contraceptives, bearing children, and having a tubal ligation or hysterectomy were associated with a similar reduction in the odds ratios for ovarian cancer among women with and without endometriosis. In particular, the use of oral contraceptives for >10 years was associated with a substantial reduction in risk among women with endometriosis (odds ratio, 0.21; 95% CI, 0.08-0.58). CONCLUSION: Women with endometriosis are at an increased risk of epithelial ovarian cancer. Long-term oral contraceptive use may provide substantial protection against the disease in this high-risk population.     

Cancer incidence in a cohort of infertile women who underwent in vitro fertilization

OBJECTIVE: To assess whether ovarian hyperstimulation and IVF increase the risk for cancer. DESIGN: Historical cohort analysis. SETTING; IVF units of two medical centers in Israel. PATIENT(S): Five thousand twenty-six women who underwent IVF between 1981 and 1992. INTERVENTION(S); Cancer incidence rates were determined through linkage to the National Cancer Registry and were compared with expected rates with respect to age, sex, and place of birth. MAIN OUTCOME MEASURE(S): Development of cancer. RESULT(S): Twenty-seven cases of cancer were observed, and 35.6 were expected (standardized incidence ratio, 0.76 [95% CI, 0.50-1.10]). Eleven cases of breast cancer were observed, whereas 15.86 were expected (standardized incidence ratio, 0.69 [95% CI, 0.46-1.66]). One case of ovarian cancer and 1 case of cervical cancer were observed, compared with 1.74 and 1.73 cases expected, respectively. The type of infertility, number of IVF cycles, and treatment outcome did not significantly affect risk for cancer. CONCLUSION(S): In a cohort of women treated with IVF, no excess risk for cancer was noted.     

Fertility drugs and the risk of breast and ovarian cancers: results of a long-term follow-up study

OBJECTIVE: To investigate a possible linkage between the use of fertility drugs for infertility and the risk of breast and ovarian cancers. DESIGN: Long-term, historic-prospective study. SETTING: Fertility clinic in a university hospital. PATIENT(S): Files of 1,197 infertile women with a mean (+/- SD) follow-up of 17.9+/-5 years (21,407 person-years) were reviewed. Diagnoses, number of courses, and dosage of fertility drugs were extracted from the files. INTERVENTION(S): Cancers were identified by record linkage to the National Cancer Registry. Histopathologic reports and data on estrogen and progesterone receptors in breast cancer tissue were also reviewed. MAIN OUTCOME MEASURE(S): Standardized incidence ratio with 95% confidence interval (CI) were used for risk assessment. RESULT(S): Of 20 breast cancers (standardized incidence ratio, 1.40 [95% CI, 0.83-2.10]), 16 were detected among 780 women who had been exposed to 3,978 cycles of clomiphene citrate (CC) and/or hMG (standardized incidence ratio, 1.65 [95% CI, 0.94-2.68]). The standardized incidence ratio for this cancer was significantly increased only in patients with one or two CC treatments and a dose of < or =1,000 mg (2.6 [1.19-5.0] and 2.52 [1.21-4.64], respectively). Two cases of ovarian cancer (1 patient unexposed) were observed with no evidence of excessive risk. Six of the eight patients with data on estrogen and progesterone receptors were exposed to CC, and all tested positive for these receptors. CONCLUSION(S): An association between the use of fertility drugs and an increased risk of breast and ovarian cancers has not been confirmed.     

Increased rate of endometriosis and spontaneous abortion in an in vitro fertilization program: no correlation with epidemiological factors.

BACKGROUND: There are conflicting data concerning endometriosis and spontaneous abortion (SAB). The aim of the present study was to evaluate if there was any association between endometriosis and SAB. Moreover, we investigated risk factors in women with endometriosis and SAB. METHODS: The medical files of 457 married women with endometriosis and 200 infertile women without endometriosis were studied retrospectively. All cases were diagnosed by laparoscopy. Data concerning demographic variables and menstrual characteristics were recorded from 226 women with endometriosis, which were divided into two groups. Group 1 included 126 cases with endometriosis and SAB, and Group 2 comprised 100 parous women with endometriosis and without SAB. Statistical comparisons between groups were made using the chi(2) test and odds ratios (OR) and 95% confidence intervals (CI). RESULTS: The proportion of SAB was significantly higher in women with endometriosis than in infertile women without endometriosis (126/457 (27.6%) vs. 36/200 (18.0% ); OR = 1.7, 95% CI 1.1 = 2.6; p = 0.01). The frequency of nulligravid women was significantly higher in women with endometriosis than in the control group (OR = 1.9, 95% CI 1.4 - 2.81; p = 0.001). Mean age, age at onset of endometriosis, race, height, weight, body mass index, medical history of allergies, and family histories of endometriosis and cancer were similar in women with endometriosis and SAB and in parous women with endometriosis but without SAB. Moreover, the two groups were similar in age at menarche, length of cycle, duration and amount of flow, and the severity of disease. The incidence of infertility was significantly higher in women with SAB (p < 0.001). CONCLUSION: These data suggest but do not prove that the risk of SAB is increased in women with endometriosis. The epidemiological risk factors of endometriosis are not associated with an increase in the abortion rate.     

Oral contraceptive use and risk of endometriosis

Objective To analyse the association between use of oral contraception and risk of pelvic endometriosis.
Design We compared use of oral contraception in women with and without endometriosis.
Participants Eligible for the study were women with primary or secondary infertility (   n = 393  ) or chronic pelvic pain (   n = 424  ). requiring laparoscopy, consecutively observed between September 1995 and January 1996 in 15 obstetrics and gynaecology departments in Italy.
Results Out of the 817 women included in the study, 345 had a diagnosis of endometriosis; 164 (47.5%) women with endometriosis and 139 (29.4%) without the disease reported ever using oral contraception. In comparison with never users the estimated odds ratios (OR) of endometriosis were 1.8 (95% CI 1.0–3.3) in current users and 1.6 (95% CI 1.1–2.4) in exusers. No clear relation emerged between duration of oral contraceptive use and risk of endometriosis. In comparison with never users, the OR was 1.8 (95% CI 1.1–3.0) for women reporting their last use of oral contraception < 5 years before interview and 1.5 (95% CI 0.9–2.5) for those reporting their last use >5 years before interview.
Conclusions The study suggests that oral contraception is associated with an increased risk of endometriosis but this finding is based on a selected population and cannot generalised to all women with endometriosis.     

Childhood tumor risk after treatment with ovulation-stimulating drugs

OBJECTIVE: To assess childhood cancer risk among children conceived following the use of ovulation-stimulating drugs. DESIGN: Record linkage study. SETTING: Infertility patients and their offspring as identified through medical records. PATIENT(S): Cohort of 30,364 Danish women evaluated for infertility beginning in the early 1960s. MAIN OUTCOME MEASURE(S): Standardized incidence ratios (SIRs) compared cancer incidence in the children to the Danish population. Case-cohort techniques calculated rate ratios (RRs) according to prior maternal drug exposures. RESULT(S): A total of 51 cancers were identified among the study children, resulting in an SIR of 1.14 (95% confidence interval [CI] 0.8-1.5). Usage of any fertility drug was associated with an RR of 0.82 (95% CI 0.4-1.6) and clomiphene citrate with an RR of 0.77 (95% CI 0.4-1.6). Tumors occurring early in life and nonhematopoietic malignancies (including neuroblastomas) were not associated with drug usage. Nonsignificant elevations in the risk of cancers occurring later in life, especially childhood hematopoietic malignancies (RR for use of any ovulation-stimulating drugs of 2.30, 95% CI 0.8-6.6), may have been related to underlying reasons for medication usage. CONCLUSION(S): Although the findings of this study are reassuring, additional adequately powered studies should continue monitoring the effects of ovulation-stimulating drugs on specific tumors, including hematopoietic malignancies.     

Gender of offspring and maternal ovarian cancer risk

OBJECTIVE: A single live birth compared to nulliparity significantly reduces the risk for ovarian cancer, but exactly how pregnancy reduces ovarian cancer risk is unknown. We sought to determine whether offspring gender, which differentially alters maternal hormonal milieu, may be associated with maternal ovarian cancer risk. METHODS: Parous women (n = 511) with incident ovarian cancer were compared to parous community controls (n = 1136) participating in a population-based case-control study of ovarian cancer (Delaware Valley, 1994-1998). In subgroup specific models for women with one, two, or three births, multivariate logistic regression was used to assess the relationship between ovarian cancer and offspring gender, adjusting for age, race, education, oral contraceptives, breast feeding, tubal ligation, and ovarian cancer family history. RESULTS: Compared to having all girls, women with all boys tended to have a reduced risk of ovarian cancer (OR = 0.80 95% CI: 0.58, 1.10), while women with boys and girls conferred the greatest protection (OR = 0.58, 95% CI: 0.43, 0.79). Among women with two births, the association was observed for those with one boy and one girl (OR = 0.63, 95% CI: 0.40, 1.00), but not for those with two male offspring (OR = 1.12, 95% CI: 0.68, 1.85). This result was consistent among women with three births (OR = 0.42, 95% CI: 0.21, 0.84; OR = 0.47, 95% CI: 0.23, 0.95; OR = 0.49, 95% CI: 0.20, 1.21; for one, two, and three boys, respectively, compared to all girls). CONCLUSION: Compared to having all girls, bearing both male and female offspring may be associated with a decrease in maternal ovarian cancer risk, although the biologic relevance of this observation is unclear.     

Risk factors for ovarian cancer in Taiwan: a case-control study in a low-incidence population

OBJECTIVE: We conducted a case-control study to identify risk factors for ovarian cancer in Taiwan, a low-incidence population where the incidence has been on the rise. METHODS: Cases were 86 women (age range 20-75, median 47) drawn from patients with primary, invasive epithelial ovarian cancer diagnosed between 1993 and 1998 in the Taipei metropolitan area, with the following histologic subtypes: 35% serous, 27% mucinous, 21% endometrioid, 15% clear cell, and 2% unspecified adenocarcinoma. Controls were 369 women (age range 20-75, median 44) selected from patients who were hospitalized at the same time for treatment of unrelated diseases. Subjects were interviewed in person regarding sociodemographic and reproductive characteristics, family and medical history, and diet. RESULTS: A strong inverse relationship of ovarian cancer to each live birth was observed (odds ratio (OR) = 0.43, 95% confidence interval (CI) = 0.20-0.89; OR = 0.30, 95% CI = 0.13-0.69; and OR = 0.18, 95% CI = 0.05-0.62 for parity of 1 or 2, 3-5, and >5, respectively). Menopause was associated with increased risk of disease (OR = 2.15, 95% CI = 1.21-3.83). A trend toward protection was seen with breastfeeding for more than 1 year (OR = 0.55, 95% CI = 0.29-1.01). No dietary factor was associated with an increased disease risk. Milk intake was associated with a decreased disease risk (OR = 0.45, 95% CI = 0.28-0.74). CONCLUSION: The strong protective effect of parity was supported by this study, and the decline in parity is likely an important reason for the rising incidence of ovarian cancer in Taiwan. A decreased disease risk was also seen with milk intake. In addition, the difference in the distribution of histologic subtypes in this population compared with high-incidence populations may point to further differences in risk factors.     

Benign gynecologic conditions among participants in the Breast Cancer Prevention Trial

OBJECTIVE: This study was undertaken to report on the benign gynecologic conditions occurring among women with an intact uterus at enrollment in the Breast Cancer Prevention Trial of the National Surgical Adjuvant Breast and Bowel Project. STUDY DESIGN: The incidence rates of several benign gynecologic conditions were determined and risks were compared among women receiving tamoxifen and those receiving placebo, based on risk ratios (RRs) with 95% CIs. Comparisons included stratification by menopausal status, body mass index, and history of estrogen use. RESULTS: Compared with women taking placebo, premenopausal women taking tamoxifen had a greater incidence of endometrial polyps (RR = 1.9, 95% CI = 1.55-2.41), leiomyomas (RR = 1.3, 95% CI = 1.14-1.55), endometriosis (RR = 1.9, 95% CI = 1.35-2.70), ovarian cysts (RR = 1.5, 95% CI = 1.20-1.78), and gynecologic surgical procedures, including hysterectomy (RR = 1.6, 95% CI = 1.29-1.88). Postmenopausal women taking tamoxifen also had an increased incidence of endometrial polyps (RR = 2.4, 95% CI = 1.76-3.24), leiomyomas (RR = 1.4, 95% CI = 1.04-1.80), endometriosis (RR = 1.9, 95% CI = 1.29-5.58), and gynecologic surgical procedures, including hysterectomy (RR = 2.2, 95% CI = 1.60-3.13), compared with women taking placebo. All women taking tamoxifen also had an increased incidence of simple endometrial hyperplasia without atypia (overall RR = 2.06, 95% CI = 1.64-2.60) compared with those taking placebo. CONCLUSIONS: Our results strongly support the estrogen agonist role of tamoxifen as the causative factor for the increased risk of endometrial polyps, leiomyomas, endometriosis, and endometrial hyperplasia among women taking this agent.     

Impact of endometriosis on implantation. Data from the Wilford Hall Medical Center IVF-ET Program

OBJECTIVE: To investigate the effect of endometriosis on implantation. STUDY DESIGN: In a retrospective cohort study, 149 consecutive in vitro fertilization retrieved cycles were analyzed. Patients with endometriosis (n = 27, 31 cycles) were compared with a control group with tubal infertility (n = 104, 118 cycles). The main outcome measure was implantation rate (gestational sac per transferred embryo). RESULTS: The patients in the tubal infertility group were slightly younger and tended to have a better response to stimulation and increased number of oocytes retrieved than did the patients in the endometriosis group; however, there were no differences in fertilization rates, number of embryos transferred or clinical pregnancy rates per cycle between the endometriosis group and tubal infertility group. The overall clinical pregnancy rate per cycle was similar for women in the endometriosis and tubal infertility groups (54.8% and 55.1%, respectively). The implantation rate was not different in the endometriosis versus tubal infertility group (28% [28/100] and 29.8%, [108/363], respectively; P = .75, relative risk = .94, 95% confidence interval .66, 1.34). CONCLUSION: For women undergoing in vitro fertilization-embryo transfer with endometriosis, the implantation rate is not markedly different from that for women undergoing in vitro fertilization-embryo transfer with tubal infertility.