Lymphedema after regional nodal irradiation for breast cancer: a retrospective cohort study

We aimed to analyze the occurrence of lymphedema as a side effect in patients who underwent regional nodal irradiation (RNI) following surgery for breast cancer.

This retrospective study was conducted on patients with breast cancer who underwent surgery from July 2014 to October 2020 at Inje University Busan Paik Hospital. The analysis included 113 cT1-3N1-3M0 breast cancer patients who underwent RNI as part of radiotherapy (RT). Mostly, surgeries were performed using breast-conserving surgery (n = 99, 87.6%), except for 14 patients with modified radical mastectomy. The total RT dose for RNI was 45-60 Gy, and the fraction size was 1.8-2.0 Gy. Most patients underwent chemotherapy (n = 98, 86.7%), including taxanes (n = 92, 81.4%).

The median follow-up was 61.1 months (range, 5.0-110.5 months). Lymphedema occurred in 54 patients (47.8%) after surgery. Twenty of them (17.7%) developed a new onset of lymphedema after RT, while 34 (30.1%) detected lymphedema before the completion of RT. Over the follow-up, 16 patients (14.2%) experienced recurrence. High radiation dose (>50.4 Gy) for RNI (P = 0.003) and taxane use (P = 0.038) were related to lymphedema occurrence after RT. Moreover, lymphedema occurrence after RT was also related to recurrence after surgical resection (P = 0.026). Breast-conserving surgery was related to early-onset lymphedema before the completion of RT (P = 0.047). Furthermore, the degree of lymph node dissection (≤4) was related to the overall occurrence of lymphedema (P = 0.045).

Considering a reduction in RNI dose may be beneficial in mitigating the incidence of lymphedema after RT in patients with breast cancer.