Lymphedema and Axillary-Lateral Thoracic Vessel Juncture Irradiation: A Clinical Dilemma

Regional nodal irradiation (RNI) is one of the main causes of breast cancer-related lymphedema (BCRL). However, studies on the relationship between the radiation dose to the axillary-lateral thoracic vessel juncture (ALTJ) region and BCRL have reported conflicting results. Based on these findings, we aimed to evaluate the clinical relevance of the dose to the ALTJ region in our patient cohort.

Patients diagnosed with breast cancer and who were treated at Koç University Hospital between 2016 and 2022 and received RNI were included. BCRL was defined as a difference in arm circumference between the ipsilateral and contralateral limb >2.5 cm at any single encounter or ≥2 cm on ≥2 visits. ALTJ was retrospectively contoured, and doses were recorded as equivalent dose (α/β = 3).

Of the 129 patients (median age 49 years) who met the inclusion criteria, 12 (9.3%) had lymphedema. Two-thirds of the patients (66.7%) were stage II, and one-third (33.3%) were stage III. The median follow-up was 22 months. The median (range) ALTJ D_mean dose was 18.11 (1.87-50) Gy, the median ALTJ D_max was 44.53 (12.8-71.1) Gy, and the median ALTJ V35 was 38% (1-100%). No significant association was determined between ALTJ parameters and BCRL.

There is insufficient data to define ALTJ as an OAR for decreasing BCRL risk. It is not appropriate to define dose and target based on ALTJ. Prospective studies with larger patient populations are needed to clarify the relationship between ALTJ and lymphedema.