Audio Journal of Oncology Podcast

RAPCHEM Study Shows Risk-Based Radiotherapy De-Escalation is Safe After Primary Systemic Therapy for Early Breast Cancer An interview with: Fleur Mauritz MD, Resident in Radiation Oncology, MAASTRO Institute of Radiation Oncology and Research, Maastricht, Netherlands BACELONA, Spain—Radiation therapy after primary systemic therapy for early breast cancer can be safely de-escalated according to risk in the light of 10-year follow-up findings from the RAPCHEM study reported at the 2026 European Breast Cancer Conference. First author Fleur Mauritz MD, who is a resident in radiation oncology at the MAASTRO Institute of Radiation Oncology and Research in Maastricht, Netherlands, gave the Audio Journal of Oncology’s Peter Goodwin the latest: AUDIO JOURNAL OF ONCOLOGY; Fleur Mauritz MD IN: [GOODWIN]”….Welcome to the ….. OUT: ….for the Audio Journal of Oncology, Goodbye.” 6:08secs EBCC 2026 Abstract no: 1, ‘Radiotherapy Long term results of Radiation therapy de-escalation in cT1-2N1 breast cancer After Primary CHEMotherapy (RAPCHEM: BOOG 2010-03): 10-year follow-up results of a Dutch, prospective, registry study’ Authors: Mauritz1,, L. de Munck2,, J. Simons3,, J. Verloop2,, T. van Dalen4,, P. Elkhuizen5,, A. Scholten5,, R. Houben1,, A.E. van Leeuwen6,, S. Linn7,, R. Pijnappel8,, P. Poortmans9,10, L. Strobbe11,, J. Wesseling12,, A. Voogd2,13, L. Boersma1,. 1Maastricht University Medical Centre+, Dept. of Radiation Oncology Maastro- GROW Research Institute for Oncology and Developmental Biology, Maastricht, The Netherlands. 2Netherlands Comprehensive Cancer Organisation, Dept. of Research and Development, Utrecht, The Netherlands. 3Erasmus MC, Dept. of Radiation Oncology, Rotterdam, The Netherlands. 4Erasmus MC, Dept. of Surgery, Rotterdam, The Netherlands. 5Antoni van Leeuwenhoek Hospital, Dept. of Radiation Oncology, Amsterdam, The Netherlands. 6f Dutch Breast Cancer Research Group, BOOG Study Center, Amsterdam, The Netherlands. 7Antoni van Leeuwenhoek Hospital, Dept. of Medical Oncology, Amsterdam, The Netherlands. 8University Medical Centre Utrecht, Dept. of Radiology, Utrecht, The Netherlands. 9Iridium Netwerk, Dept. of Radiation Oncology, Wilrijk-Antwerp, Belgium. 10University of Antwerp, Faculty of Medicine and Health Sciences, Wilrijk-Antwerp, Belgium. 11Canisius Wilhelmina Hospital Nijmegen, Dept. of Surgery, Nijmegen, The Netherlands. 12Antoni van Leeuwenhoek Hospital, Dept. of Pathology, Amsterdam, The Netherlands. 13Maastricht University Medical Centre+, Dept. Epidemiology- GROW Research Institute for Oncology and Developmental Biology, Maastricht, The Netherlands. BACKGROUND The five-year results of the RAPCHEM study (De Wild et al, 2022) and the recently published NSABP-B51 trial (Mamounas et al, 2025) suggest that locoregional radiation therapy (RT) can be tailored to the ypN-status in cT1-2N+ breast cancer (BC) patients treated with primary systemic treatment (PST). However, long-term results are lacking. Here we present the 10-year results of the RAPCHEM study, a prospective registry study, evaluating the long-term safety of tailoring locoregional RT to the nodal response after PST, for locoregional recurrence rate (LRR), recurrence free interval (RFI) and overall survival (OS). MATERIAL AND METHODS From January 2011 to January 2015, cT1-2N+M0 (<4 suspicious nodes at imaging) BC patients were prospectively included. Patients were treated with PST followed by lumpectomy or mastectomy in combination with a sentinel lymph node biopsy (SNLB) and/or removal of marked axillary lymph nodes (MARI), or an axillary lymph node dissection (ALND). cN+ status was histologically confirmed. Three risk groups were defined based on ypN-status, with corresponding RT strategy. Low-risk group (ypN0): whole breast RT (WBRT) after lumpectomy, no RT after mastectomy. Intermediate-risk group (ypN1): WBRT or chest wall RT, and in case of no ALND, RT of axillary levels 1-2. High-risk group (ypN2+): WBRT or chest wall RT, RT of the non-resected part of the axilla (levels 3-4 after ALND, and levels 1-4 if no ALND) with/without internal mammary nodes RT. The endpoints of the current analysis were 10-year LRR, RFI and OS. RFI was defined as time between primary diagnosis until first event (either local, regional, or distant recurrence, or death from BC). Kaplan-Meier survival analysis was used, and log-rank test to compare differences between groups. RESULTS Of the 848 included patients, ten were lost to follow-up. Twenty-four patients had a LRR without synchronous distant metastases. The 10-year LRR was 2.7% for the total cohort, and 2.1%, 3.2% and 2.8% respectively, for the low-, intermediate- and high-risk group. The 10-year RFI was 79.2% and the 10-year OS was 83.0%, both with significant differences between risk groups (Table 1). CONCLUSION De-escalation of locoregional RT after PST appears to be safe in terms of LRR. Stratification in risk groups seems appropriate, even when omitting regional RT (and chest wall RT in case