Racial disparities in adoption of axillary sentinel lymph node biopsy and lymphedema risk in women with breast cancer.

Abstract

Racial disparities exist in many aspects of breast cancer care. Sentinel lymph node biopsy (SLNB) was developed to replace axillary lymph node dissection (ALND) for staging early breast cancer to minimize complications. Racial disparities in the use of SLNB remain incompletely characterized, and their effect on lymphedema risk is not known. To determine racial differences in SLNB use among patients with pathologically node-negative breast cancer during the period when SLNB became the preferred method for axillary staging as well as whether such differences affect lymphedema risk. A retrospective study was conducted using the Surveillance, Epidemiology, and End Results-Medicare-linked database from 2002 through 2007 to identify cases of incident, nonmetastatic, pathologically node-negative breast cancer in women aged 66 years or older. Sentinel lymph node biopsy use and 5-year cumulative incidence of lymphedema by race. Of 31 274 women identified, 1767 (5.6%) were black, 27 856 (89.1%) were white, and 1651 (5.3%) were of other or unknown race. Sentinel lymph node biopsy was performed in 73.7% of white patients and 62.4% of black patients (P < .001). The use of SLNB increased by year for both black and white patients (P < .001); however, a fixed disparity of approximately 12 percentage points in SLNB use persisted through 2007. In adjusted analysis, black patients were significantly less likely than white patients to undergo SLNB (odds ratio, 0.67; 95% CI, 0.60-0.75; P < .001). Overall, the 5-year cumulative lymphedema risk was 8.2% in whites and 12.3% in blacks (hazard ratio [HR], 1.43; 95% CI, 1.23-1.67; P < .001). When stratified by type of axillary surgery, 5-year lymphedema risk was 6.8% in whites undergoing SLNB (HR, 1 [reference]), 8.8% in blacks undergoing SLNB (HR, 1.28; 95% CI, 1.02-1.60; P = .03), 12.2% in whites undergoing ALND (1.79; 1.63-1.96; P < .001), and 18.0% in blacks undergoing ALND (2.76; 2.25-3.39; P < .001). Although SLNB use increased in both black and white patients with pathologically node-negative breast cancer from 2002 through 2007, the rates of SLNB remained lower in black than white patients during this entire period by approximately 12 percentage points. This racial disparity in SLNB use contributed to racial disparities in lymphedema risk. Improvements in the dissemination of new techniques are needed to avoid disparities in breast cancer care and patient outcomes, particularly in disadvantaged groups.