Identifying the Axillary Substructure at Risk for Lymphedema in Operable Patients With Breast Cancer Receiving...

Area of Science:

• Oncology
• Radiation Oncology
• Lymphedema Research

Background:

• Breast cancer-related lymphedema (BCRL) is a significant complication following axillary lymph node dissection (ALND) and regional nodal irradiation (RNI).
• Specific axillary substructures may be implicated in BCRL development, necessitating identification of high-risk regions for targeted dose reduction.

Purpose of the Study:

• To compare dose-volume parameters of axillary substructures to identify regions associated with BCRL.
• To evaluate the clinical applicability of identified dose constraints for BCRL risk mitigation.

Main Methods:

• A cohort of 336 breast cancer patients undergoing ALND and RNI were assessed for BCRL using the Norman questionnaire.
• Thirteen dose-volume parameters across 8 axillary substructures were analyzed for association with BCRL.
• Additional cohorts evaluated recurrence risk and treatment plan reoptimization feasibility for identified high-risk substructures.

Main Results:

• The cumulative incidence of BCRL was 33.9% over a median follow-up of 60 months.
• The axillary-lateral thoracic vessel juncture (ALTJ)-V35Gy ≥ 79.2% was the most significant dosimetric predictor of BCRL.
• A predictive nomogram incorporating clinical factors and ALTJ-V35Gy showed good accuracy (AUC 0.769-0.780); ALTJ reoptimization was feasible without compromising radiotherapy quality.

Conclusions:

• ALTJ-V35Gy < 79.2% is proposed as a dose constraint to reduce BCRL risk in patients undergoing RNI post-ALND.
• Avoiding excessive radiation to the ALTJ is clinically feasible and safe, potentially mitigating BCRL without compromising target coverage.