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Background Chronic inflammatory responses initiated by lymphatic injury play a key role in the pathophysiology of secondary lymphedema. However, it is unclear if baseline inflammation or ethnic/racial variability in inflammatory responses increase lymphedema risk. Crown-like structures of the breast (CLS-B), consisting of macrophages engulfing necrotic adipocytes, are a marker of systemic inflammation and have been implicated in the pathogenesis of breast cancer, but their role in lymphedema development is unknown. Here we determine whether baseline differences in inflammation, characterized by the presence of CLS-B, contributed to lymphedema risk in a diverse cohort of patients treated with ALND. Methods Patients ≥ 18 years undergoing ALND were enrolled in a prospective lymphedema screening study. Body mass index (BMI) and volumetric arm measurements (perometer) were performed at baseline, postoperatively, and every 6 months. Breast tissue obtained at definitive surgery was assessed for CLS-B with CD-68 IHC stain in non-tumor breast tissue. Inflammation severity was determined by number of CLS-B/cm2, with the median used to differentiate between mild and severe inflammation. Lymphedema was defined as a relative arm volume change of ≥10%. Lymphedema incidence was assessed using competing risk analysis and compared between patients with and without CLS-B. Uni- and multivariable analysis was performed to identify factors associated with lymphedema development. Results Between 11/2016-03/2020, 304 ALND patients were enrolled; 281 had at least 6 months of follow-up and were included in the study. Eleven percent self-identified as Asian, 20% Black, 6% Hispanic, and 60% White. Median age was 48 years; median BMI was 26.3 kg/m2, with higher BMI observed in Black and Hispanic women compared to Asian and White women (p < 0.001). Overall, 54% had CLS-B, with severe inflammation (> 0.4 CLS-B/cm2) identified in 71 (25%) patients. CLS-B presence correlated with BMI (36% [BMI < 25], 63% [BMI 25-30], 70% [BMI > 30], p < 0.001) and varied across racial/ethnic groups, with a higher prevalence in Black and Hispanic women (68% [Black], 69% [Hispanic] vs 59% [Asian], 46% [White], p = 0.03) (Table). Inflammation severity did not differ by race/ethnicity (p = 0.11). At 2.1 years median follow-up (IQR 1.6-3.1), 66 women developed lymphedema, with a 2-year lymphedema rate of 21.3% (95% CI 16.4-26.8). Lymphedema incidence was higher among Black and Hispanic women, compared to Asian and White women (2-year rate: 33.8% [Black], 31% [Hispanic], 17.4% [Asian], 18.2% [White], p = 0.002), and was higher among women with CLS-B (2-year rate: 28.2% [CLS-B] vs 12.9% [no CLS-B], p = 0.02). On multivariable analysis, Black race (White [referent]: HR 2.85, 95% CI 1.4-5.8; p = 0.03), receipt of NAC (upfront surgery [referent]: HR 2.46, 95% CI 1.04-5.8, p = 0.04) and older age (HR 1.03, 95% CI 1.01-1.06 per 1-year increase; p = 0.009) were independently associated with lymphedema development, while CLS-B was not (HR 1.37, 95% CI 0.81-2.34, p = 0.2). Conclusions In a prospective cohort of patients treated with ALND, Black race, receipt of NAC, and increasing age, but not CLS-B, were independently associated with lymphedema risk. However, the higher CLS-B prevalence in Black women suggests that they may have a propensity for increased inflammation, which may in part be contributing to the higher lymphedema risk observed, but is likely not the only inflammatory mechanism that modulates risk. Table. Clinical characteristics of study cohort stratified by the presence of CLS-B Citation Format: Andrea V. Barrio, Giacomo Montagna, Varadan Sevilimedu, Ethan Gomez, Dilip Giri, Babak Mehrara, Monica Morrow. Does Breast Inflammation Contribute to Lymphedema Risk in Patients Treated with Axillary Lymph Node Dissection? [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-08-09. |
