Racial segregation and disparities in breast cancer care and mortality

BACKGROUND.

Questions have existed as to whether residential segregation is a mediator of racial/ethnic disparities in breast cancer care and breast cancer mortality, or has a differential effect by race/ethnicity.

METHODS.

Data from the Surveillance, Epidemiology, and End Results–Medicare database on white, black, and Hispanic women aged 66 to 85 years with breast cancer were examined for the receipt of adequate breast cancer care.

RESULTS.

Blacks were less likely than whites to receive adequate breast cancer care (odds ratio [OR], 0.78; 95% confidence interval [CI], 0.71‐0.86). Individuals, both black and white, who lived in areas with greater black segregation were less likely to receive adequate breast cancer care (OR, 0.73; 95% CI, 0.64‐0.82). Black segregation was a mediator of the black/white disparity in breast cancer care, explaining 8.9% of the difference. After adjustment, adequate care for Hispanics did not significantly differ from whites, but individuals, both Hispanic and white, who lived in areas with greater Hispanic segregation were less likely to receive adequate breast cancer care (OR, 0.73; 95% CI, 0.61‐0.89). Although Blacks experienced greater breast cancer mortality than whites, black segregation did not substantially mediate the black‐white disparity in survival, and was not significantly associated with mortality (hazards ratio, 1.03; 95% CI, 0.87‐1.21). Breast cancer mortality did not differ between Hispanics and whites.

CONCLUSIONS.

Among seniors, segregation mediates some of the black‐white disparity in breast cancer care, but not mortality. Individuals who live in more segregated areas are less likely to receive adequate breast cancer care. Cancer 2008. © 2008 American Cancer Society.     

Racial disparities in colorectal cancer survival

BACKGROUND:

Racial/ethnic differences in colorectal cancer (CRC) survival have been documented throughout the literature. However, the reasons for these disparities are difficult to decipher. The objective of this analysis was to determine the extent to which racial/ethnic disparities in survival are explained by differences in sociodemographics, tumor characteristics, diagnosis, treatment, and hospital characteristics.

METHODS:

A cohort of 37,769 Medicare beneficiaries who were diagnosed with American Joint Committee on Cancer stages I, II, and III CRC from 1992 to 2002 and resided in 16 Surveillance, Epidemiology, and End Results (SEER) regions of the United States was identified in the SEER‐Medicare linked database. Survival was estimated using the Kaplan‐Meier method. Cox proportional hazards modeling was used to estimate hazard ratios (HRs) of mortality and 95% confidence intervals (CIs).

RESULTS:

Black patients had worse CRC‐specific survival than white patients, but the difference was reduced after adjustment (adjusted HR [aHR], 1.24; 95% CI, 1.14‐1.35). Asian patients had better survival than white patients after adjusting for covariates (aHR, 0.80; 95% CI, 0.70‐0.92) for stages I, II, and III CRC. Relative to Asians, blacks and whites had worse survival after adjustment (blacks: aHR, 1.56; 95% CI, 1.33‐1.82; whites: aHR, 1.26; 95% CI, 1.10‐1.44). Comorbidities and socioeconomic Status were associated with a reduction in the mortality difference between blacks and whites and blacks and Asians.

CONCLUSIONS:

Comorbidities and SES appeared to be more important factors contributing to poorer survival among black patients relative to white and Asian patients. However, racial/ethnic differences in CRC survival were not fully explained by differences in several factors. Future research should further examine the role of quality of care and the benefits of treatment and post‐treatment surveillance in survival disparities. Cancer 2010. © 2010 American Cancer Society.     

Racial disparities in cancer therapy

BACKGROUND: The purpose of this study was to determine whether racial disparities in cancer therapy had diminished since the time they were initially documented in the early 1990s. METHODS: The authors identified a cohort of patients in the SEER-Medicare linked database who were ages 66 to 85 years and who had a primary diagnosis of colorectal, breast, lung, or prostate cancer during 1992 through 2002. The authors identified 7 stage-specific processes of cancer therapy by using Medicare claims. Candidate covariates in multivariate logistic regression included year, clinical, and sociodemographic characteristics, and physician access before cancer diagnosis. RESULTS: During the full study period, black patients were significantly less likely than white patients to receive therapy for cancers of the lung (surgical resection of early stage, 64.0% vs 78.5% for blacks and whites, respectively), breast (radiation after lumpectomy, 77.8% vs 85.8%), colon (adjuvant therapy for stage III, 52.1% vs 64.1%), and prostate (definitive therapy for early stage, 72.4% vs 77.2%, respectively). For both black and white patients, there was little or no improvement in the proportion of patients receiving therapy for most cancer therapies studied, and there was no decrease in the magnitude of any of these racial disparities between 1992 and 2002. Racial disparities persisted even after restricting the analysis to patients who had physician access before their diagnosis. CONCLUSIONS: There has been little improvement in either the overall proportion of Medicare beneficiaries receiving cancer therapies or the magnitude of racial disparity. Efforts in the last decade to mitigate cancer therapy disparities appear to have been unsuccessful.     

Racial/ethnic disparities in survival among men diagnosed with prostate cancer in Texas

BACKGROUND:

To the authors' knowledge, few studies to date have examined racial differences in prostate cancer survival while controlling for socioeconomic status (SES). No such studies have examined this association in Texas, a large state with significant ethnic and racial diversity. The objective of this analysis was to determine whether racial disparities in survival for men diagnosed with prostate cancer in Texas from 1995 through 2002 remained after adjusting for SES, rural residence, and stage of disease.

METHODS:

A cohort of 87,449 men who were diagnosed with prostate cancer was identified from the Texas Cancer Registry. The SES measure was based on census tract data reflecting median household income, median home value, and percentages of men living below poverty, with a college education, and with a management or professional occupation. The 5‐year survival rates were calculated using the Kaplan‐Meier method and Cox proportional hazard modeling was used to estimate hazard ratios (HRs) for race and all‐cause and disease‐specific mortality.

RESULTS:

After adjusting for SES, age, stage of disease, tumor grade, year of diagnosis, and rural residence, both black and Hispanic men were more likely (adjusted HR [aHR], 1.70 [95% confidence interval (95% CI), 1.58‐1.83] and aHR, 1.11 [95% CI, 1.02‐1.20], respectively) to die of prostate cancer compared with white men. The pattern of survival disadvantage for black men held for those diagnosed with localized disease and advanced disease, and for those with an unknown stage of disease at diagnosis.

CONCLUSIONS:

Substantial racial disparities in prostate cancer survival were found for men in Texas. Future studies should incorporate treatment data as well as comorbid conditions because this information may explain noted survival disparities. Cancer 2011. © 2010 American Cancer Society.     

Racial and ethnic disparities in breast cancer rates by age: NAACCR Breast Cancer Project

Summary Objective. To examine age-specific rates of breast cancer incidence among racial and ethnic groups in the United States.Methods. Subjects were 363,801 women diagnosed with invasive breast cancer diagnosed during 1994–1998 and reported in the North American Association of Central Cancer Registries (NAACCR) data set. Variables analyzed included race, ethnicity, 5-year age group (from 10 years through 85+ years), and stage at time of diagnosis (localized, regional, distant). Incidence rates per 100,000 women were calculated for each 5-year age group and stratified by stage. Rate ratios and 95% confidence intervals were calculated by comparing each racial group with whites and Hispanics with non-Hispanics.Results. Black women experience significantly higher breast cancer incidence up to the age of 40 years and significantly lower incidence after age 50 compared with white women of the same ages. This is called the ‘crossover’ effect. This shifting burden of higher incidence occurs at ages 35–39 for localized stage and at ages 55–59 for regional stage. For distant stage, black women of all ages experience higher incidence compared with white women. Similar crossover effects do not exist for American Indian (AI) or Asian/Pacific Islander (API) women compared with white women. Both AI and API women have significantly lower incidence of breast cancer compared with white women, and Hispanic women have significantly lower incidence compared with non-Hispanic women.Conclusions. This study highlights racial and ethnic differences in breast cancer incidence rates among US women. The crossover effect between black and white women, particularly the lower incidence of localized stage disease diagnosed in older black women, is a significant phenomenon that may be associated with screening practices, and has implications for public health planning and cancer control initiatives to reduce racial/ethnic disparities.     

Racial disparities in surgical treatment and survival of epithelial ovarian cancer in United States

OBJECTIVE: To compare the racial differences in treatment and survival of epithelial ovarian cancer patients. METHODS: Data were obtained from the Surveillance, Epidemiology, and End Results Program between 1988 and 2001 and analyzed using Kaplan-Meier methods and Cox proportional hazards regression. RESULTS: Of the 24,038 women, 22,407 (93.2%) were non-Hispanic White, and 1,631 (6.8%) were African-American. Median age of Whites versus African-Americans was 65 versus 63 years, respectively (P < 0.001). Of the patients with early-stage (I-II) disease, 38.8% of Whites underwent lymphadenectomy with their primary surgery compared to only 32.8% of African-Americans (P = 0.005). In the overall study group, the 5-year disease-specific survival of Whites was significantly higher compared to the African-Americans (44.1% vs. 40.7%, P = 0.001). On multivariable analysis, age, race, stage, cell type, and grade of disease were all independent prognostic factors for survival. CONCLUSION: Our data suggest that race is an independent prognostic factor for survival in epithelial ovarian cancer. In addition, African-Americans with early-stage cancer were less likely to undergo lymphadenectomy with their staging procedure. Furthermore, patient/physician education is needed to increase the number of patients undergoing surgical staging procedures for epithelial ovarian cancer.     

Association between standard clinical and pathologic characteristics and the 21-gene recurrence score in breast cancer patients: a population-based study

BACKGROUND: The 21-gene recurrence score (RS) assay has been reported to accurately predict the risk of disease recurrence and chemotherapy benefit in women with estrogen receptor (ER)-positive, lymph node (LN)-negative breast cancer who are treated with tamoxifen. To the authors' knowledge, the association between the RS and clinicopathologic characteristics has been studied in randomized and case-control trials, but not in the general population. METHODS: The authors analyzed the correlation between clinicopathologic breast cancer characteristics and RS among 300 consecutive Israeli patients who were referred to undergo the test between October 2004 and October 2006. RESULTS: Low, intermediate, and high RS were noted in 109 patients (36%), 134 patients (45%), and 57 patients (19%), respectively. The median age of the patients was 54 years and the median tumor size was 1.6 cm. High tumor grade, low progesterone receptor expression, infiltrating ductal histology, and high HER-2 expression were found to be associated with a high RS, whereas patient age, tumor size, ER expression, and lymph node micrometastasis were found to correlate poorly with the RS. The ability of any of these variables, either alone or in combination, to predict the RS was limited. Similarly, neither commonly used guidelines nor the Adjuvant! Online software were found to be able to predict the RS. CONCLUSIONS: The results of the current study suggest that neither standard clinicopathologic features nor commonly used assessment tools can reliably predict the RS among referred breast cancer patients compared with a clinical trial population. These data also may indicate the need for additional studies regarding the role of the RS among certain subsets of breast cancer patients, including those with noninfiltrating ductal carcinoma histology and the presence of lymph node micrometastasis.     

Racial and ethnic differences in breast cancer survival

BACKGROUND: The reasons for race/ethnicity (R/E) differences in breast cancer survival have been difficult to disentangle. METHODS: Surveillance, Epidemiology, and End Results (SEER)-Medicare data were used to identify 41,020 women aged > or =68 years with incident breast cancer between 1994-1999 including African American (2479), Hispanic (1172), Asian/Pacific Island (1086), and white women (35,878). A Cox proportional hazards model assessed overall and stage-specific (0/I, II/III, and IV) R/E differences in breast cancer survival after adjusting for mammography screening, tumor characteristics at diagnosis, biologic markers, treatment, comorbidity, and demographics. RESULTS: African American women had worse survival than white women, although controlling for predictor variables reduced this difference among all stage breast cancer (hazards ratio [HR], 1.08; 95% confidence interval [95% CI], 0.97-1.20). Adjustment for predictors reduced, but did not eliminate, disparities in the analysis limited to women diagnosed with stage II/III disease (HR, 1.30; 95% CI, 1.10-1.54). Screening mammography, tumor characteristics at diagnosis, biologic markers, and treatment each produced a similar reduction in HRs for women with stage II/III cancers. Asian and Pacific Island women had better survival than white women before and after accounting for all predictors (adjusted all stages HR, 0.61 [95% CI, 0.47-0.79]; adjusted stage II/III HR, 0.61 [95% CI, 0.47-0.79]). Hispanic women had better survival than white women in all and stage II/III analysis (all stage HR, 0.88; 95% CI, 0.75-1.04) and stage II/III analysis (HR, 0.88; 95% CI, 0.75-1.04), although these findings did not reach statistical significance. There was no significant difference in survival by R/E noted among women diagnosed with stage IV disease. CONCLUSIONS: Predictor variables contribute to, but do not fully explain, R/E differences in breast cancer survival for elderly American women. Future analyses should further investigate the role of biology, demographics, and disparities in quality of care.     

Racial disparities in the use of radiotherapy after breast‐conserving surgery: A national Medicare study

BACKGROUND:

In prior studies, the use of standard breast cancer treatments has varied by race, but previous analyses were not nationally representative. Therefore, in a comprehensive, national cohort of Medicare patients, racial disparities in the use of radiotherapy (RT) after breast‐conserving surgery (BCS) for invasive breast cancer were quantified.

METHODS:

A national Medicare database was used to identify all beneficiaries (age >65 years) treated with BCS for incident invasive breast cancer in 2003. Claims codes identified RT use, and Medicare demographic data indicated race. Logistic regression modeled RT use in white, black, and other‐race patients, adjusted for demographic, clinical, and socioeconomic covariates.

RESULTS:

Of 34,080 women, 91% were white, 6% were black, and 3% were another race. The mean age of the patients was 76 ± 7 years. Approximately 74% of whites, 65% of blacks, and 66% of other‐race patients received RT (P < .001). After covariate adjustment, whites were found to be significantly more likely to receive RT than blacks (odds ratio, 1.48; 95% confidence interval, 1.34‐1.63 [P < .001]). Disparities between white and black patients varied by geographic region, with blacks in areas of the northeastern and southern United States demonstrating the lowest rates of RT use (57% in these regions). In patients age <70 years, racial disparities persisted. Specifically, 83% of whites, 73% of blacks, and 78% of other races in this younger group received RT (P < .001).

CONCLUSIONS:

In this comprehensive national sample of older breast cancer patients, substantial racial disparities were identified in RT use after BCS across much of the United States. Efforts to improve breast cancer care require overcoming these disparities, which exist on a national scale. Cancer 2010. © 2009 American Cancer Society.     

Having health insurance does not eliminate race/ethnicity-associated delays in breast cancer diagnosis in the District of Columbia

BACKGROUND:

Delays in follow‐up after breast cancer screening contribute to disparities in breast cancer outcomes. The objective of this research was to determine the impact of race/ethnicity and health insurance on diagnostic time, defined as number of days from suspicious finding to diagnostic resolution.

METHODS:

This retrospective cohort study of 1538 women examined for breast abnormalities between 1998‐2010 at 6 hospitals/clinics in the District of Columbia measured mean diagnostic times between non‐Hispanic whites (NHWs), non‐Hispanic blacks (NHBs), and Hispanics with private, government, or no health insurance by using a full‐factorial ANOVA model.

RESULTS:

Respective average—geometric mean (95% CI)—diagnostic times (in days) for NHWs, NHBs, and Hispanics were 16 (12, 21), 27 (23, 33), and 51 (35, 76) among privately insured; 12 (7, 19), 39 (32, 48), and 71 (48, 105) among government insured; 45 (17, 120), 60 (39, 92), and 67 (56, 79) among uninsured. Government insured NHWs had significantly shorter diagnostic times than government insured NHBs (P = .0003) and Hispanics (P < .0001). Privately insured NHWs had significantly shorter diagnostic times than privately insured NHBs (P = .03) and Hispanics (P < .0001). Privately insured NHBs had significantly shorter diagnostic times than uninsured NHBs (P = .03).

CONCLUSIONS:

Insured minorities waited >2 times longer to reach their diagnostic resolution than insured NHWs. Having private health insurance increased the speed of diagnostic resolution in NHBs; however, their diagnostic time remained significantly longer than for privately insured NHWs. These results suggest diagnostic delays in minorities are more likely caused by other barriers associated with race/ethnicity than by insurance status. Cancer 2011;. © 2011 American Cancer Society.     

Genome-wide methylation patterns provide insight into differences in breast tumor biology between American women of African and European ancestry

American women of African ancestry (AA) are more likely than European-Americans (EA) to be diagnosed with aggressive, estrogen receptor (ER) negative breast tumors; mechanisms underlying these disparities are poorly understood. We conducted a genome wide (450K loci) methylation analysis to determine if there were differences in DNA methylation patterns between tumors from AA and EA women and if these differences were similar for both ER positive and ER negative breast cancer. Methylation levels at CpG loci within CpG islands (CGI)s and CGI-shores were significantly higher in tumors (n=138) than in reduction mammoplasty samples (n=124). In hierarchical cluster analysis, there was separation between tumor and normal samples, and in tumors, there was delineation by ER status, but not by ancestry. However, differential methylation analysis identified 157 CpG loci with a mean β value difference of at least 0.17 between races, with almost twice as many differences in ER-negative tumors compared to ER-positive cancers. This first genome-wide methylation study to address disparities indicates that there are likely differing etiologic pathways for the development of ER negative breast cancer between AA and EA women. Further investigation of the genes most differentially methylated by race in ER negative tumors can guide new approaches for cancer prevention and targeted therapies, and elucidate the biologic basis of breast cancer disparities.