Adjuvant radiation therapy after preoperative chemotherapy

Abstract

The decision to treat patients with radiotherapy after preoperative chemotherapy is still largely based on the initial clinical staging of the patients. The use of three-field radiotherapy (RT) including the chest wall/breast and regional lymphatics after surgery in locally advanced, node-positive patients receiving neoadjuvant systemic chemotherapy is well established. Patients with clinically staged T3-T4 tumors, pathological non-complete responders in the axilla, and younger patients (<35) with cT2N1 or worse disease should be treated with RT according to retrospective data. A pooled analysis of the National Surgical Adjuvant Breast and Bowel Project (NSABP) B18 and B27 trials is the only prospective dataset that can assist radiotherapy decisions in the neoadjuvant setting. Although the results of this analysis should be validated with modern studies (i.e., proper anti-Her-2 and hormonal treatment), selected patients (cT1-2, cN1, and >40 years old) with pathological complete response (pCR) (ypT0, ypTis, ypN0) and non-triple-negative histology after neoadjuvant chemotherapy could possibly be followed without postmastectomy radiotherapy (PMRT) and without regional irradiation in a breast-conserving setting. Well-designed randomized, controlled studies are urgently needed in this controversial area.