BACKGROUND:Blacks have lower survival rates for colon cancer than whites, possibly related to more advanced stages of disease at diagnosis and to socioeconomic differences between blacks and whites. While the black/white difference in colon cancer survival is well documented, the few studies that have investigated this difference have been limited by the modest number and type of explanatory factors that were considered.PURPOSE:We analyzed data from the National Cancer Institute Black/White Cancer Survival Study to determine 1) what characteristics might contribute to the racial difference in colon cancer survival and 2) if a survival disparity remained between black and white patients after adjustment was made for these characteristics.METHODS:This prospective study included 454 blacks and a stratified random sample of 521 whites, aged 20-79 years, with cancer of the colon diagnosed from January 1, 1985, through December 31, 1986, and who were residents of the metropolitan areas of Atlanta, New Orleans, and San Francisco/Oakland. Follow-up was truncated on December 31, 1990. Cox proportional hazards regression was used to estimate the death rate among blacks relative to that among whites after adjustment for potential explanatory factors, including sociodemographic factors, concurrent (comorbid) medical conditions, stage at diagnosis, tumor characteristics, and treatment. All P values were calculated from two-tailed tests of statistical significance.RESULTS:After adjustment for age, sex, and geographic area, the black-to-white mortality hazard ratio (HR) was 1.5 (95% confidence interval [CI] = 1.2-1.9), indicating that the risk of death among black patients was 50% higher than that among white patients. Further adjustment for stage reduced the excess cancer mortality to 20% (HR = 1.2; 95% CI = 1.0-1.5), decreasing the overall racial difference in excess mortality from 50% to 20% or to a 60% reduction in excess mortality. Although adjustment for poverty reduced the excess mortality by 20%, adjusting for both stage and poverty did not further reduce the racial difference. Among patients with stages II and III disease, blacks had lower survival rates than whites (HR = 1.8; 95% CI = 1.0-3.1 and HR - 1.5; 95% CI = 1.0-2.3, respectively). Among those patients with metastatic disease (stage IV), survival was similar for whites and blacks.CONCLUSIONS:Stage at diagnosis accounted for more than half of the excess colon cancer mortality observed among blacks. Poverty and other socioeconomic conditions, general health status, tumor characteristics, and general patterns of treatment did not further explain the remaining survival disadvantage among blacks.IMPLICATIONS:Because the racial disparity was confined to earlier stages, future studies should investigate whether blacks have more advanced disease at diagnosis and whether less aggressive treatment is provided because of understanding.

Background: Numerous studies have reported differences in cancer staging at diagnosis and in survival between Black and White patients with breast cancer. Utilizing data obtained from the National Cancer Institute's (NCI's) Black/White Cancer Survival Study for the period 1985-1986, a new study is presented here that systematically examines multiple explanatory factors (e.g., lack of mammograms) associated with these cancer-staging differences. Purpose: We evaluated within a single study the relationship of selected demographic, lifestyle, antecedent medical experiences, and health care acces s factors to cancer staging at diagnosis in Black and White breast cancer patients. Methods: Data utilized in this population-based cohort study of 1222 eligible women (649 Black and 573 White) newly diagnosed for the period 1985-1986 with histologically confirmed primary breast cancer were obtained from the NCI's Black/White Cancer Survival Study. Sources of data included abstracts of hospital medical records, central review of histology slides by a study consultant pathologist, and patient interviews obtained from three metropolitan areas: Atlanta, New Orleans, and San Francisco-Oakland. Within each area, 70% of all Black incident cases were randomly selected, and a sample of White cases, frequency matched by age groups (20-49 years, 50-64 years, and 65-79 years), was selected for comparison. Stage of breast cancer at diagnosis was classified according to the international tumor-lymph node-metastases (TNM) system. Statistical models utilized in this study included the log-linear and polychotomous logistic regression with multiple predictor variables. Results: Factors associated with cancer staging were differentially expressed in Blacks and Whites. Indicators of access to health care, a lack of mammograms, and an increased body mass index significantly (P<.02) contributed to stage differences in Blacks, whereas income was marginally associated (P = .06) with stage for Whites only. Nuclear grade, having a breast examination by a physician, and a history of patient delay explained approximately 50% of the excess risk for stage III-IV Cancer versus stage I-II(N0) cancer among Blacks compared with Whites (odds ratio- reduction from 2.19 to 1.68). Conclusion: These findings suggest that no single factor or group of factors can explain more than half of the race-stage differences noted in this study with respect to Black and White breast cancer patients.

BACKGROUND:Numerous studies have reported differences in cancer staging at diagnosis and in survival between Black and White patients with breast cancer. Utilizing data obtained from the National Cancer Institute's (NCI's) Black/White Cancer Survival Study for the period 1985-1986, a new study is presented here that systematically examines multiple explanatory factors (e.g., lack of mammograms) associated with these cancer-staging differences.PURPOSE:We evaluated within a single study the relationship of selected demographic, lifestyle, antecedent medical experiences, and health care access factors to cancer staging at diagnosis in Black and White breast cancer patients.METHODS:Data utilized in this population-based cohort study of 1222 eligible women (649 Black and 573 White) newly diagnosed for the period 1985-1986 with histologically confirmed primary breast cancer were obtained from the NCI's Black/White Cancer Survival Study. Sources of data included abstracts of hospital medical records, central review of histology slides by a study consultant pathologist, and patient interviews obtained from three metropolitan areas: Atlanta, New Orleans, and San Francisco-Oakland. Within each area, 70% of all Black incident cases were randomly selected, and a sample of White cases, frequency matched by age groups (20-49 years, 50-64 years, and 65-79 years), was selected for comparison. Stage of breast cancer at diagnosis was classified according to the international tumor-lymph node-metastases (TNM) system. Statistical models utilized in this study included the log-linear and polychotomous logistic regression with multiple predictor variables.RESULTS:Factors associated with cancer staging were differentially expressed in Blacks and Whites. Indicators of access to health care, a lack of mammograms, and an increased body mass index significantly (P < .02) contributed to stage differences in Blacks, whereas income was marginally associated (P = .06) with stage for Whites only. Nuclear grade, having a breast examination by a physician, and a history of patient delay explained approximately 50% of the excess risk for stage III-IV cancer versus stage I-IIN0 cancer among Blacks compared with Whites (odds ratio reduction from 2.19 to 1.68).CONCLUSION:These findings suggest that no single factor or group of factors can explain more than half of the race-stage differences noted in this study with respect to Black and White breast cancer patients.