Clinical Experience of Axillary Radiotherapy for Node-positive Breast Cancer

Area of Science:

• Oncology
• Radiotherapy
• Breast Cancer Management

Background:

• Axillary node clearance (ANC) and regional nodal irradiation (RNI) are standard treatments for node-positive breast cancer.
• ANC is linked to significant complications like lymphoedema and shoulder stiffness.
• The AMAROS trial demonstrated RNI's non-inferiority to ANC in survival and recurrence, with improved quality of life.

Purpose of the Study:

• To evaluate the real-world experience with RNI in a large patient population.
• To compare the efficacy and toxicity of RNI with ANC, using AMAROS trial data as a benchmark.
• To contribute evidence to the ongoing discussion on managing node-positive breast cancer.

Main Methods:

• Retrospective analysis of 190 patients treated with RNI between 2006-2009.
• Comparison with 681 patients from the AMAROS RNI arm.
• Data collection included overall survival, cancer-specific survival, recurrence rates, and toxicities (lymphoedema, brachial plexopathy, stiffness).
• Subgroup analysis for patients meeting POSNOC trial criteria.

Main Results:

• Locoregional recurrence rates were 3.16% for this study's RNI cohort versus 1.82% in AMAROS.
• Cancer-specific survival was higher in this study's cohort compared to AMAROS.
• Lymphoedema rates were 5.8% for RNI, significantly lower than 11% for AMAROS RNI and 23% for ANC.
• POSNOC status, particularly in oestrogen receptor-positive patients, indicated a low-risk group (HR 0.42).

Conclusions:

• RNI demonstrates non-inferior survival and recurrence outcomes compared to ANC, with a more favorable toxicity profile.
• The findings support the continued use of RNI for node-positive breast cancer patients.
• Further research is needed for personalized treatment de-escalation and intensification based on tumor biology.