No Access to Radiotherapy Cannot Explain Reduced Survival in Black Women Post–Breast Cancer Surgery
Black women who undergo mastectomy or lumpectomy for advanced breast cancer have shorter survival duration than their white, Hispanic, and Asian counterparts, regardless of whether they undergo radiation therapy after the procedure, according to a new study (Martinez SR, et al. Cancer. Epub ahead of print. June 20, 2011).
Radiation therapy is recommended for all patients who undergo mastectomy or lumpectomy. In a previous study, black women with advanced breast cancer were less likely than whites or Asians to receive radiotherapy. Therefore, the investigator wanted to find out whether this disparity in access to radiotherapy would explain the poorer survival in black women with metastatic breast cancer.
In this new study, the researchers used data from the Surveillance, Epidemiology and End Results to identify women with breast cancer associated with ≥10 metastatic lymph nodes diagnosed between 1988 and 2005. A total of 12,653 met the study eligibility criteria.
Radiation therapy was associated with a 22% all-cause decreased risk of death and a 19% disease-specific reduced mortality risk from breast cancer; however, black race was associated with a 54% all-cause increased mortality and a 53% breast cancer– specific increased mortality risk.
This pattern did not change after stratifying the results by type of surgery and the use of radiation therapy. The use of radiation therapy improved OS and disease-specific survival in whites and Asians, but not in blacks.
The persistence of this disparity in survival regardless of use of radiation therapy and type of surgery, the investigators note, suggests that limited access to radiotherapy does not explain the poorer survival rates among black women with metastatic breast cancer. They add that black women may be less responsive to radiation therapy, and their poorer OS rates may be associated with comorbidities, or with tumor-related biology that require further investigation in this specific subpopulation.
A study that focuses on black women with metastatic breast cancer is, therefore, warranted, the authors note, to elucidate the cause for this disparity in survival rates.