RAPCHEM Study Shows Risk-Based Radiotherapy De-Escalation is Safe After Primary Systemic Therapy for Early Breast Cancer
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’
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.
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).
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.
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).
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 of mastectomy) in the low-risk group, and RT of levels 3-4 in the intermediate-risk group.
Breast cancer recurrence remains low, even after ten years, with radiotherapy tailored to patient’s individual risk
Barcelona, Spain: The chances of breast cancer recurring remain very low when patients are treated with radiotherapy that is tailored to their individual risk following chemotherapy and surgery. These are the findings of a ten-year study presented at the 15th European Breast Cancer Conference (EBCC15) in Barcelona today (Wednesday).
In the study, radiotherapy treatment was selected according to whether there were still signs of breast cancer cells in patients’ lymph nodes after chemotherapy and surgery. For women with no signs of cancer remaining in the lymph nodes, this approach meant minimal or even no radiotherapy. Scaling treatment down can in turn reduce side-effects for patients.
The research was presented by Dr Fleur Mauritz, a radiation oncologist in training at Maastro, Maastricht Radiation Oncology Institute, The Netherlands. She said: “For many patients with breast cancer, the first treatment is chemotherapy. This can shrink the tumour and kill off any cancer cells that are starting to spread into the body, before surgery.
“We know that radiotherapy reduces the risk of breast cancer recurrence, especially when patients have had surgery to remove a tumour, rather than the whole breast, and when there are signs of cancer in the lymph nodes. This study examined whether it’s possible to scale back radiotherapy in patients whose cancer shows a good response when chemotherapy is given prior to surgery.”
The study included 848 patients who were treated at 17 cancer centres in The Netherlands between 2011 and 2015. Each patient had a small breast tumour (measuring under five centimetres) with signs of cancer spread in only one, two or three lymph nodes.
Following chemotherapy and surgery, the patients were categorised into three different risk groups. Patients who no longer had signs of cancer in their lymph nodes were categorised as low risk and were given radiotherapy to the breast if their surgery removed the tumour, or no radiotherapy if they had their breast removed (mastectomy). Patients who had signs of cancer in only one to three lymph nodes were categorised as intermediate risk and treated with radiotherapy to the breast area without irradiating the nearby lymph nodes. Patients with signs of cancer in four or more lymph nodes, were categorised as high risk and treated with radiotherapy to the breast area and the lymph nodes in the surrounding area.
In the following ten years, only 24 out of all 838 patients who completed follow-up (2.9%) experienced a recurrence in the breast, chest wall or lymph nodes (without signs of cancer spread elsewhere in the body). In the low-risk group, seven out of 291 patients (2.4%) developed a recurrence; in the intermediate-risk group, 12 out of 370 patients (3.2%) developed a recurrence; and in the high-risk groups five out of 177 patients (2.8%) developed a recurrence. [1]
Dr Mauritz said: “The results of our study show that tailoring the extent of radiotherapy according to how well the chemotherapy has worked to treat cancer in the lymph nodes, leads to very low and reassuring recurrence rates in the breast and surrounding area. In a selected group of patients, we see very low recurrence rates even when we leave radiotherapy out completely.
“A major strength of our study is that it’s the first to demonstrate the benefits of tailoring radiotherapy for this group of patients over a ten-year period. It is important to note that most patients in the study underwent axillary lymph node dissection, a procedure that was common ten years ago but is used less often in current practice. This study did not compare patients treated with and without radiation therapy. For the final conclusion, we will have to wait for the results of a randomised trial from the USA, which are expected in three years.” [2]
Dr Mauritz and her colleagues plan to study more about the risk factors for breast cancer recurrence, for example looking at tumour characteristics, and precisely where cancer recurs, to help refine radiotherapy in the future.
The Chair of EBCC15, Professor Isabel Rubio, Head of Breast Surgical Oncology at the Clínica Universidad de Navarra in Madrid, Spain, was not involved in this research. She said: “Reducing radiotherapy after chemotherapy appears safe in terms of the risk of recurrence. Choosing the amount of treatment based on the risk of recurrence also seems appropriate: radiotherapy may be omitted in low-risk patients after mastectomy, while in intermediate-risk patients, targeted radiotherapy remains advisable. Overall, this study reinforces that stratifying patients by risk, which supports more personalised treatment, helps to ensure the most appropriate approach while avoiding both overtreatment and undertreatment.”
Dr Mauritz is delivering the young investigator innovation award lecture at EBCC15.
Fleur Mauritz, Audio Journal of Oncology EBCC TEXT 2026 April 3rd, 2026
