Factors Associated with Chronic Breast Lymphedema After Adjuvant Radiation in Women Undergoing Breast Conservation Therapy
Zhu S, Atisha D, Evangelistia M, Barry R, Rama S, Ghosh S, Cannella C, Chen Y, Bensenhaver J, Levin KJ, and Walker EM. Factors Associated with Chronic Breast Lymphedema After Adjuvant Radiation in Women Undergoing Breast Conservation Therapy. International Journal of Radiation Oncology Biology Physics 2020; 108(3):e32.
International Journal of Radiation Oncology Biology Physics
Purpose/Objective(s): Unlike temporary breast edema caused by post-lumpectomy radiation therapy (RT), the edema that persists beyond one year is not well defined and difficult to treat. The aim of this study is to define the incidence and risk factors for the development of chronic breast lymphedema in women undergoing lumpectomy with RT at a large metropolitan cancer center.
Materials/Methods: A retrospective chart review was performed on all patients who underwent lumpectomy from 2014 to 2017. Women who did not undergo RT at our institution and those with stage IV disease were excluded from the analysis. Patient demographics, comorbidities, operative data, RT data and postoperative complications were obtained. Chronic breast lymphedema (CBL) was defined as edema that persisted beyond one-year post completion of radiation therapy. Breast volumes were determined by contoured breast volumes or, if unavailable, estimated by the 95% isodose volumes from the RT treatment planning system. Using a density curve, the distribution of breast volumes was plotted for patients with and patients without CBL. Univariate analysis was used to evaluate factors associated with CBL. Multivariate regression analysis was used to evaluate factors associated with the risk of CBL while accounting for potential confounding variables as defined by the univariate analysis.
Results: A total of 811 patients were included for analysis. Fifty-seven (7.0%) patients developed breast lymphedema beyond one year. For the entire cohort, mean age was 63.3 years old, mean BMI was 31.21 kg/m2, and mean breast volume was 1195 cc (SD = 643.25 cc). Compared to the cohort that did not develop CBL (n = 754), the CBL cohort (n = 57) had a higher BMI (33.10 kg/m2 vs. 29.84 kg/m2, p<0.001), higher percentage of black race (61.4% vs. 43.8%, P = 0.024), larger breast volume (1504 cc vs. 1081 cc, P<0.001), greater number of lymph nodes taken at time of surgery (3 vs. 1, P<0.001), higher percentage that had underwent ALND (12.3% vs. 5.2%, P = 0.036), and larger size of lumpectomy specimen (118.95 cm3 vs. 96.00 cm3, P = 0.016). The density curve determined that the optimal cutoff for breast volume was around 1300 cc. When accounting for potential confounding variables, multivariate regression analysis revealed that those whose breast volume > 1300 cc (vs. <1300 cc) were 2.5 times more likely to experience breast lymphedema after one year (OR = 2.53, p = 0.005). When volume was evaluated as a continuous variable, regression analysis revealed that for every 1cc increase in breast volume, the risk of breast lymphedema increases by 0.1% (OR = 1.001, P = 0.001).
Conclusion: Chronic breast lymphedema presents a clinical concern for women undergoing lumpectomy with postoperative radiation, particularly women with larger breasts. Further studies should focus on preventative strategies, as well as the psychosocial and economic impact of this morbidity.