Black women had a 3.85-fold increased risk of developing lymphedema following treatment for breast cancer compared to White women, according to the results from a study by Barrio et al being presented at the 2021 San Antonio Breast Cancer Symposium (Abstract GS4-01). In addition, the researchers found that Black race was the strongest predictor of lymphedema development, and that women who received neoadjuvant chemotherapy followed by axillary lymph node dissection were twice as likely to develop lymphedema compared with women who had upfront surgery followed by axillary lymph node dissection.
The aim of this study was to evaluate the impact of race and ethnicity on breast cancer–related lymphedema incidence and severity in a prospective cohort of patients treated with axillary lymph node dissection using defined measurement protocols.
The researchers enrolled 304 patients with breast cancer who underwent axillary lymph node dissection between November 2016 and March 2020; 268 of the patients had at least one longitudinal measurement after baseline in the analysis. Sixty-two percent of the patients were White, 21% were Black, 11% were Asian, and 6% were Hispanic.
Black women in the study were older (P = .007), had higher baseline body mass index (BMI) (P = .001), and were more likely to be clinically node-positive (P = .016) compared with White, Asian, and Hispanic women. Both Black and Hispanic women were more likely to undergo breast-conserving surgery (P = .037) and receive nodal radiation therapy (P = .02).
The researchers measured arm volume and BMI at baseline, postoperatively, and at 6-month intervals. They defined breast cancer–related lymphedema as a relative volume change of 10% or greater from the baseline.
The patient groups were compared using Wilcoxon rank-sum and Fischer’s exact tests. Univariate and multivariable analysis were used to calculate the odds ratio (OR) of developing breast cancer–related lymphedema and to compare severity of lymphedema.
The researchers’ findings show that at a median follow-up of 1.62 years, 50 women developed breast cancer–related lymphedema. The 18-month breast cancer–related lymphedema rate for the entire cohort was 15.9% (95% confidence interval [CI] = 11.5%–21.8%). Black and Hispanic women had a higher incidence of breast cancer–related lymphedema compared to Asian and White women (18-month-rate: 30.9 % for Black women, 20.2% for Hispanic women, 10.6% for Asian women, 11.8% for White women; P = .004). On multivariable analysis, Black race was the strongest predictor of breast cancer–related lymphedema development (White [referent]: OR = 4.41, 95% CI = 2.42–8.10, P < .001); Asian race and Hispanic ethnicity were not associated with breast cancer–related lymphedema.
Other factors, including receipt of neoadjuvant chemotherapy (upfront surgery [referent]: OR = 1.89, 95% CI = 1.02–3.63, P = .043), older age (OR = 1.04, 95% CI = 1.01–1.06 per 1-year increase), increasing number of lymph nodes removed (OR = 1.05, 95% CI = 1.01–1.09 per 1 additional lymph node, P = .007), and a longer follow-up interval (OR = 1.60, 95% CI = 1.31–1.96 per 6-month increase, P < .001) were also independently associated with breast cancer–related lymphedema development.
When assessing breast cancer–related lymphedema severity, Black women were 3.85 times more likely to have a higher relative volume change compared to White women (P = .007), with no difference in breast cancer–related lymphedema severity identified in Hispanic and Asian women.
“In this prospective screening study, Black and Hispanic women had a higher incidence of breast cancer–related lymphedema development compared to White women, with Black race being the strongest predictor of breast cancer–related lymphedema development and of severe breast cancer–related lymphedema. Further work should address the biologic mechanisms behind racial disparities in the risk of breast cancer–related lymphedema and possible preventive strategies,” concluded the study authors.
In a statement regarding the study’s results, lead author Andrea V. Barrio, MD, Associate Attending Physician in the Breast Service, Department of Surgery at Memorial Sloan Kettering Cancer Center, said that by increasing understanding of lymphedema, researchers may be able to help design strategies to reduce the risk. In addition, since research has proven that Black women are often diagnosed with later-stage breast cancer, they are more likely to need the axillary surgery that gives rise to lymphedema. Still, Black race was the strongest predictor of lymphedema development. Understanding the links between race, cancer treatment, and the effects of treatment could ultimately help improve quality of life for patients with breast cancer and survivors, said Dr. Barrio.
Disclosure: Funding for this study was provided by the Chanel Endowment for Survivorship Research and the Manhasset Women’s Coalition Against Breast Cancer.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.