Abstract GS4-01: 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

Abstract

Abstract Background Epidemiological and self-reported data suggest that Black women may be at increased risk of developing breast cancer related lymphedema (BCRL) after axillary lymph node dissection (ALND), however prospective clinical data is lacking. BCRL risk for other racial minorities has not been well studied. We sought to evaluate the impact of race and ethnicity on BCRL incidence and severity in a prospective cohort of patients treated with ALND using defined measurement protocols. Methods Patients undergoing ALND were enrolled in a prospective BCRL screening study with arm volume (perometer) measurements and body mass index (BMI) evaluated at baseline, post-operatively, and at 6-month intervals. BCRL was defined as a relative volume change (RVC) ≥ 10% from baseline. Groups were compared using Wilcoxon rank-sum and Fischer’s exact tests. Univariate (UVA) and multivariable analysis (MVA) were used to calculate the odds ratio (OR) of developing BCRL and to compare severity of BCRL. Results From 11/2016-03/2020, 304 patients were enrolled; 268 had at least one longitudinal measurement after baseline and are included in the study. Sixty-two percent of patients were Caucasian, 21% were Black, 11% were Asian and 6% were Hispanic. 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 Caucasian, Asian and Hispanic women. Both Black and Hispanic women were more likely to undergo breast-conserving surgery (p = 0.037) and receive nodal RT (p = 0.02) (Table). At a median follow-up of 1.62 years, 50 women developed BCRL. The 18-month BCRL rate for the entire cohort was 15.9% (95%CI, 11.5% - 21.8%). Black and Hispanic women had a higher incidence of BCRL compared to Asian and Caucasian women (18-month-rate: 30.9 % [Black]; 20.2% [Hispanic] vs 10.6% [Asian]; 11.8% [Caucasian], p = 0.004). On MVA, Black race was the strongest predictor of BCRL development (Caucasian [referent]): OR 4.41, 95%CI 2.42-8.10; p < 0.001); Asian race and Hispanic ethnicity were not associated with BCRL. Other factors, including receipt of NAC (upfront surgery [referent]): OR 1.89, 95%CI 1.02-3.63; p = 0.043), older age (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 = 0.007) and a longer follow-up interval (OR 1.60, 95%CI 1.31-1.96 per 6-month increase; p < 0.001) were also independently associated with BCRL development. When assessing BCRL severity, Black women were 3.85 times more likely to have a higher relative volume change compared to Caucasian women (p = 0.007), with no difference in BCRL severity identified in Hispanic and Asian women (p = NS). Conclusions In this prospective screening study, Black and Hispanic women had a higher incidence of BCRL development compared to Caucasian women, with Black race being the strongest predictor of BCRL development and of severe BCRL. Further work should address the biologic mechanisms behind racial disparities in the risk of BCRL and possible preventive strategies. Table: Clinical Characteristics of study cohort stratified by race/ethnicityOverall#(n = 268)Caucasian(n = 161)Black (n = 54)Asian(n = 29)Hispanic (n = 16)P-valueAge (years)48. (40,57)49. (40,59)50. (42,55)44. (35,52)44. (33,49)0.007Baseline BMI (kg/m2)26.2. (22.5,31.1)25.2. (22.4,30.4)29.9. (25.9,34.0)22.1. (20.6,29.1)28.1. (23.5, 32.9)< 0.001cT. 1/2. 3/4180 (67%). 88 (33%)103 (64%). 58 (36%)36 (67%). 18 (33%)25 (86%). 4 (14%)12 (75%). 4 (25%)0.5cN. 0. 1. 2/372 (27%). 173 (65%). 23 (9%)46 (29%). 102 (63%). 13 (8%)8 (15%). 45 (83%). 1 (2%)12 (41%). 14 (48%). 3 (11%)3 (19%). 9 (56%). 4 (25%)0.016Histology. Ductal. Lobular or mixed. Other220 (82%). 36 (13%). 12(4.5%)128 (80%). 25 (16%). 8 (5.0%)47 (87%). 5 (9.3%). 2 (3.7%)25 (86%). 2 (6.9%). 2 (6.9%)12 (75%). 4 (25%). 0 (0%)0.5Subtype. HR+/HER2-. HER2+. HR-/HER2-181 (68%). 51 (19%). 36 (13%)111 (69%). 34 (21%). 16 (10%)31 (57%). 9 (17%). 14 (26%)23 (79%). 4 (14%). 2 (7%)10 (62%). 4 (25%). 2 (12%)0.1Chemotherapy. Neoadjuvant. Adjuvant190 (71%). 78(29%)111 (69%). 50 (31%)42(78%). 12(22%)17(59%). 12(41%)14(88%). 2(12%)0.12Type of Surgery. BCS. Mastectomy67 (25%). 201 (75%)36 (22%). 125 (78%)19 (35%). 35 (65%)3(10%). 26 (90%)6(38%). 10 (62%)0.037Type of Reconstruction†. None. Autologous/flap. TE/implant55 (27%). 23 (11%). 123 (61%)36 (29%). 11(9%). 78 (63%)9 (26%). 8 (23%). 18 (51%)8 (31%). 2(7%). 16 (62%)1(10%). 1 (10%). 8 (80%)0.083Total number of lymph nodes removed18 (14,23)19 (14,24)17 (13,22)15 (12,23)22 (18,24)0.059Total number of positive nodes2 (1, 5)3 (1, 6)2 (1, 3)2 (1, 4)2 (1, 3)0.073Radiation therapy††252 (94%)149 (93%)54 (100%)26 (90%)16 (100%)0.070Nodal RT244 (91%)145 (90%)53 (98%)23 (79%)16 (100%)0.020BCS, breast conserving surgery; TE, tissue expander Frequency (column percent) reported for categorical variables and median (IQR) reported for continuous variables #Race/ethnicity was unknown in 8 cases †Applies to mastectomy only ††Includes any type of radiation Citation Format: Andrea V. Barrio, Giacomo Montagna, Varadan Sevilimedu, Ethan A. Gomez, Babak Mehrara, Monica Morrow. 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 [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr GS4-01.