Research Activities, May 2013
Racial disparities shown in the postsurgical treatment of elderly women with early-stage breast cancer
Older black women are less likely than older white women to receive chemotherapy or radiation therapy after having breast conserving surgery (BCS) for early-stage breast cancer, according to a new study. Previously, racial disparities in breast cancer mortality were attributed to black women being diagnosed when the cancer was at a later stage, fewer physician recommendations for breast cancer screening, higher rates of obesity and hypertension, as well as nonclinical factors.
In this study, the researchers compared post-surgical treatment of black and white women aged 65 or older diagnosed with early-stage breast cancer, who were treated by either BCS or mastectomy, and had close-in (proximal) lymph nodes checked for the presence of cancer cells. After adjusting their data for patient age, tumor characteristics, number of coexisting illnesses (and socioeconomic status in a second model), the researchers found that black women were less likely than white women to receive chemotherapy (25 percent less if lymph node-positive and 17 percent less if node-negative).
Adjustment for socioeconomic factors did not weaken this relationship, with a significant 27 percent reduction in the chance of chemotherapy treatment for node-positive black women aged 65–69 years when compared to similar white women. The node-positive and node-negative black women were 26 percent and 23 percent less likely to receive radiation therapy after BCS than were white women. This disparity, however, was no longer significant after adjustment for socioeconomic characteristics.
When the researchers compared all-cause mortality between the two racial groups, the differences were not significant for those women who had BCS, no radiation therapy, or radiation therapy following BCS. For node-negative women who did not receive chemotherapy, the black women had an 11 percent higher risk of dying than white women. Black women who underwent mastectomy, regardless of node status, had marginally significant higher risks of dying than did similar white women (12 percent if node-positive and 15 percent if node-negative).
The findings were based on data on 54,682 older women with stage I, II, or IIIa breast cancer from the National Cancer Institute’s SEER–Medicare linked databases for 1991–2002. The study was funded in part by AHRQ (HS17567).
More details are in "Differences in treatment and survival among African-American and Caucasian women with early stage operable breast cancer," by Kavita Sail, Ph.D., Luisa Fanzini, Ph.D., David Lairson, Ph.D., and others in the June 2012 Ethnicity & Health 17(3), pp. 309-323.