Race effects the likelihood to develop lymphoedema following breast cancer treatment

Development of breast cancer-related lymphoedema is not equally distributed between races. Black women experienced higher rates of breast cancer-related lymphoedema than White women, results of a prospective study show.

Lymphoedema is a well-known and quality-of-life lowering side effect of breast cancer treatment, particularly for women who undergo axillary lymph node dissection. Epidemiological and self-reported data suggest that Black women may be at increased risk of developing breast cancer related lymphoedema after axillary lymph node dissection, albeit that prospective clinical data is lacking. Dr Andrea Barrio (Memorial Sloan-Kettering Cancer Center, NY, USA) presented results from a prospective study investigating the impact of race and ethnicity on breast cancer related lymphoedema incidence and severity [1].

The study enrolled 304 patients and included 276 patients who had at least one longitudinal measurement after baseline included in the analysis. Sixty percent of the participants were White; 20% were Black; 11% were Asian; and 6% were Hispanic (3% did not report race or ethnicity). Black women were older (P=0.007), had higher baseline BMI (P<0.001), and were more likely to be clinically node-positive (P=0.016) compared to White, Asian, and Hispanic women. Both black and Hispanic women were more likely to undergo breast-conserving surgery (P=0.037) and receive nodal radiotherapy (P=0.02). Breast cancer-related lymphoedema was defined as a relative volume change of 10% or greater from baseline.

At a median follow-up of 1.6 years, 50 women developed breast cancer-related lymphoedema. The 24-month breast cancer-related lymphoedema rate was 20.5% for White women, 23.4% for Asian women, 27.7% for Hispanic women, and 39.4% for Black women (see Figure). Multivariate analysis showed that Black race was the strongest predictor of breast cancer-related lymphoedema development (OR 3.53; P<0.001) versus White women as reference category. Hispanic ethnicity was also associated with a higher incidence of breast cancer-related lymphoedema (OR 3.11). However, the number of Hispanic patients included was low. In addition, neoadjuvant chemotherapy was associated with a 2-fold increase (OR 2.07; P=0.017) of breast cancer-related lymphoedema incidence. Among patients with lymphoedema, there was no difference in lymphoedema severity across racial and ethnic groups, with similar relative volume changes observed.

Figure: Cumulative Incidence of Lymphedema by race/ethnicity [1].



 

 

 

“The aetiology for the higher observed incidence of lymphoedema in Black women is unknown,” said Dr Barrio. “It may be due to race-based differences in inflammatory reaction, tissue fibrosis, and lymphatic function. Future studies should address the biologic mechanisms behind racial disparities in lymphoedema development and develop possible preventive strategies.”

In addition, analysis of the data from the I-SPY trial (NCT01042379) showed that race did not significantly affect several key measures of breast cancer treatment outcomes, including pathologic complete response (OR relative to White: 1.00 for Asian and 0.89 for Black) and event-free survival (HR relative to White: 1.10; P=0.73 for Asian and 1.37; P=0.13 for Black) [2].

1. Montagna G, et al. Impact of race and ethnicity on incidence and severity of breast cancer related lymphedema after axillary lymph node dissection: Results of a prospective screening study. GS4-01, SABCS 2021 Virtual Meeting, 7–10 December.
2. Kyalwazi B, et al. Analysis of clinical outcomes and expression-based immune signatures by race in the I-SPY 2 trial. GS4-02, SABCS 2021 Virtual Meeting, 7–10 December.

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Posted on 31 January, 2022