African-American women with early-stage, invasive breast cancer were 12% less likely than Caucasian women with the same diagnosis to receive a minimally invasive technique, axillary sentinel lymph node (SLN) biopsy, even as the procedure had become the standard of surgical practice, according to research from MD Anderson Cancer Center.
The study, first presented at the 2012 CTRC-AACR San Antonio Breast Cancer Symposium and now updated and published in JAMA Surgery, also found that those African American women who underwent the older, more invasive procedure, axillary lymph node (ALN) dissection, had higher rates of lymphedema. The findings were presented by Dalliah Mashon Black, M.D., assistant professor in Surgical Oncology at MD Anderson.
SLN biopsy became the preferred practice for the staging of breast cancer in 2002 and the standard of care by 2007 when the National Comprehensive Cancer Network and other national organizations endorsed the minimally invasive procedure. The older technique, ALN dissection, is associated with a number of complications, including lymphedema. Black estimates that approximately 75% of newly diagnosed breast cancer patients are eligible for SLN biopsy.
“With this research, we wanted to determine if new surgical innovations were being incorporated equally amongst different patient populations,” said Black, also the study’s first author. “This study looks at trends over time, comparing appropriate patients who all would have been candidates for the SLN biopsy to see how the new procedure was implemented in African-Americans and Caucasians.”
For the retrospective population-based study, the MD Anderson team used Medicare claims between 2002 and 2007 from the Surveillance, Epidemiology and End Results (SEER) database to examine the surgical history of 31,274 women age 66 and older diagnosed with early-stage, invasive breast cancer. Of those women, 1,767 (5%) were African-American, 27,856 (89%) were Caucasian and 1,651 (5.3%) were other, or of unknown race.
The researchers found that 62% of African-American patients underwent the SLN biopsy, compared to 74% of the Caucasian patients. Although the SLN biopsy rate increased in both groups between 2002 and 2007, a fixed disparity persisted through the five years.
The five-year cumulative incidence of lymphedema was 12.2% in those who received ALN dissection, compared to 6.8% in those who received SLN biopsy. Overall, African-Americans had a higher rate of the complication with 18% having lymphedema after axillary node dissection; however, among those patients who had the SLN biopsy, patients had similar risk of lymphedema, regardless of race.
“The risk of lymphedema was primarily driven by differences in treatment: ALN dissection resulted in about twice the risk. When we looked at outcomes stratified by treatment, Caucasians and African-Americans had similar risks of lymphedema if they had a SLN,” said Benjamin Smith, M.D., associate professor in Radiation Oncology and the study’s senior author. “This ties the treatment disparity to a disparity in outcome.”
Overall, the findings were a surprise to Black and her team.
“We were surprised to learn that the disparity persisted through 2007 and that there was an adverse patient outcome, lymphedema, associated with the findings. However, when we controlled for tumor characteristics and types of breast surgery, there was still a significant difference,” said Black.
“SLN is a safe and integral part of the surgical management of early, invasive breast cancer. Improving patient education and creating ways to ensure all healthcare providers know practice guidelines and are able to implement them will help with this disparity. Appropriate patients with early-stage breast cancer should not opt for less than this standard in care if properly educated,” Black continued.
In addition to Black and Smith, other authors on the all-MD Anderson team include: Thomas A. Buchholz, M.D., executive vice president and physician-in-chief and head of Radiation Oncology; Henry Kuerer, M.D., Ph.D., professor in Surgical Oncology, and Jing Jiang, a senior statistical analyst in Health Services Research.
None of the authors has any declarations.