Studies explore survival and treatment disparities among black and white elderly patients with cancer
Research Activities, July 2009, No. 347
Blacks are more likely than whites in the United States to develop and die from cancer. Whether these racial disparities are due solely to race or to factors such as differences in treatment or socioeconomic status (SES) remain unanswered. Two new studies by Xianglin L. Du, M.D., Ph.D., and colleagues at the University of Texas Health Science Center examine the impact of racial disparities on lymphoma survival and track treatment disparities among patients with cancer of the colon and rectum. The first study linked factors associated with race, but not intrinsic racial differences, to non-Hodgkin lymphoma (NHL) survival disparities. The second study revealed fewer racial disparities in receipt of treatment for colorectal cancer over time. Both studies, funded in part by the Agency for Healthcare Research and Quality (HS16743), are summarized here.
Wang M., Burau, K. D., Fang, S., and others. "Ethnic variation in diagnosis, treatment, socioeconomic status, and survival in a large population-based cohort of elderly patients with non-Hodgkin lymphoma." (2008, December). Cancer 113(11), pp. 3231-3241.
An estimated 63,000 elderly persons are diagnosed with NHL in the United States each year. Whites are more likely to be struck with the disease than other groups. This study found that whites were more likely to receive life-prolonging chemotherapy than blacks. Also, poorer SES, more common among the black patients studied, was significantly associated with a higher risk of dying. There were no significant differences in all-cause and lymphoma-specific mortality rates between black and white patients after controlling for differences in treatment, SES, patient demographics, and tumor factors. Using a national cancer registry linked to the Medicare database, the researchers retrospectively examined a group of 13,321 elderly patients diagnosed with NHL from 1992 to 1999. Among these patients, 11,868 were white, 533 were black, and 920 were from other ethnic/racial groups. Nearly three-fourths of the black patients were in the lowest SES quartile compared with one-fifth of whites. Black patients were significantly less likely to receive chemotherapy than whites (43.2 vs. 52.4 percent). The risk of all-cause and NHL-specific mortality grew significantly with age, advanced cancer stage, more coexisting illnesses, and poorer SES. Five-year survival after diagnosis was higher in whites than blacks (60.3 percent vs. 55.6 percent for NHL-specific mortality) and for patients in higher SES quartiles compared with those in the lowest SES quartile. The findings suggest that factors associated with race, but not intrinsic racial differences, accounted for the racial differences in mortality, conclude the researchers.
White, A., Liu, C.-C., Xia, R., and others. "Racial disparities and treatment trends in a large cohort of elderly African Americans and Caucasians with colorectal cancer, 1991 to 2002." (2008, December). Cancer 113(12), pp. 3400-3409.
Blacks are diagnosed with colorectal cancer at a slightly younger age than whites, and have a lower percentage of 5-year survivors (55 vs. 66 percent). The majority of elderly blacks and whites with colorectal cancer receive the recommended standard of care, with racial disparities in therapy receipt among blacks relatively small and not significant, this study found. They examined data from the SEER-Medicare cancer database to study 55,204 whites and 4,599 blacks who were treated for colorectal cancer between early 1991 and late 2002. Overall, blacks were 16 percent less likely than whites to receive standard therapy for colorectal cancer (surgery, radiation, and/or chemotherapy). However, treatment differences became insignificant after adjustment for patient age at diagnosis, marital status, sex, socioeconomic status, and tumor characteristics. Racial disparities in receipt of standard therapy also declined over the study period. Treatment differences remained at about 5 percent between 1991 and 1996, peaked to 7.2 percent in 1997, then declined from 7.1 to 4 percent from 1999 to 2002. From 1991 to 2002, the percentage of patients who did not receive standard therapy for colorectal cancer declined from 24.5 to 22.4 percent for whites and from 30.4 to 26.4 percent for blacks. The study was unable to sort out the effect of patient preferences, as well as regional variations in physician practice style or health care delivery—factors that may explain some of the racial disparities in treatment.