Abstract PS1-02-13: Effects of different radiation techniques and fields on breast cancer related Lymphedema after axillary dissection and Simplified Lymphatic Microsurgical Preventive Healing Approach

Background: Patients with breast cancer undergo axillary lymph node dissection under certain indications. One of the main side effects of axillary dissection is upper limb lymphedema that occurs in 15-40% 0f cases and can be debilitating. An objective measurement of lymphedema is Bioimpedance spectroscopy, that produces an LDEX Score and can detect subclinical lymphedema. There are several risk factors for developing lymphedema after axillary dissection, among them obesity, radiation therapy, wound complication and higher age. SLYMPHA is a surgical prevention of breast cancer related lymphedema, in which the breast surgeon is performing connection of lymphatic ducts from the upper limb to venous source. This method has been proven to reduce incidence of lymphedema to 10%. Our aim is to explore the effect of different radiation techniques and fields on the development of breast cancer related lymphedema in patients after axillary dissection and and SLYMPHA. Method: We established a retrospective database of all patients who underwent axillary dissection and SLYMPHA for breast cancer from 2014-2021, and collected demographic, clinical, surgical and radiation data. For each patient we observed L-dex measurement at pre-operative setting and 6,9,12,24 months post-operative setting as well as clinical examination for LE development. Binomial logistic regression was used to identify associations between clinical data, radiation methods and field, and LE incidence. Results: Among 219 patients, 136 had LDEX assessments, with 30 patients (13.6%) developing BCRL. Factors found to be related to elevated risk of LE included older age, higher BMI, recurrent cancer, reconstructive surgery and having N2/N3 nodal disease. Radiation therapy was found to be correlated with higher levels of lymphedema, especially with radiation techniques such as Three-Dimensional Conformal Radiation Therapy and Intensity Modulated Radiation Therapy/Volumetric Modulated Arc Therapy. Radiation to chest wall field and Comprehensive radiation excluding dissected axilla fields had a higher association with increased levels of LE. Conclusions: Patients undergoing axillary dissection and SLYMPHA with higher BMI, recurrent cancer, reconstructive surgery, N2/N3 disease, or adjuvant radiation treatment, as well as those receiving Intensity Modulated Radiation Therapy/Volumetric Modulated Arc Therapy or Three-Dimensional Conformal radiation techniques, have an increased risk of developing breast cancer related LE. De-escalation of radiation and better selection of radiation techniques and fields could contribute to a better lymphedema free survivorship. Citation Format: H. Kadar Sfarad, M. Feret, C. Padilla, A. Balari, J. Janin, E. Avisar. Effects of different radiation techniques and fields on breast cancer related Lymphedema after axillary dissection and Simplified Lymphatic Microsurgical Preventive Healing Approach [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS1-02-13.