09 augustus 2022 – 20:59
Patients with cT1-2N1 breast cancer treated with neoadjuvant chemotherapy have a low chance of recurrence after less extensive radiation. In patients who received radiation therapy according to a consensus-based guideline, the disease did not recur more often or earlier than expected. In the first five years after treatment, 2.2 percent of patients experienced recurrent breast cancer. This is apparent from the RAPCHEM study, an initiative of Maastro, Maastricht University Medical Center, BOOG research group, IKNL and others. The results are published today in Lancet Oncology.
In recent years, more and more women with breast cancer have been treated with neoadjuvant (pre-operative) chemotherapy. This often causes the tumor to shrink. Chemotherapy is then followed by surgery, and radiotherapy is often followed after surgery. Due to the changed treatment with neoadjuvant chemotherapy instead of adjuvant chemotherapy, the indications for radiotherapy were no longer entirely clear, because previously the indication was always based on the pathological data without the patient having received chemotherapy first. In the first years after the start of neoadjuvant chemotherapy, the indications for radiotherapy were often based purely on the data before the start of the treatment. This led to radiotherapy more often, and to more extensive radiotherapy, than in the situation in which primary surgery was performed.
The RAPCHEM research team, supported by BOOG, hypothesized on the basis of published retrospective studies that radiotherapy could be safely de-escalated if the response in the lymph nodes to the neoadjuvant chemotherapy were taken into account in the indication. Therefore, they designed a study that aimed to evaluate the oncological safety of radiotherapy de-escalation according to a predefined, consensus-based study guideline. Research has been carried out with funding from KWF into the effectiveness of this de-escalation of treatment.
Risk of locoregional recurrence
In this study (RAPCHEM, BOOG 2010-03) data were analyzed from 838 patients with breast cancer (diagnosed in the period 2011-2015) from 17 Dutch radiotherapy centers. The consensus-based guideline described the recommendations for locoregional radiotherapy for three risk groups. Patients in the low-risk group did not receive radiotherapy to the chest wall or to the regional lymph nodes. Patients in the moderate-risk group received radiotherapy to the chest or chest wall only. The high-risk group received the usual locoregional radiotherapy, ie radiotherapy of the chest or chest wall, as well as regional lymph nodes.
Preventing late consequences
Physician-researcher Sabine de Wild: ‘Due to the late consequences that some of the patients experience after radiotherapy, such as pain, edema or reduced shoulder function, de-escalation of the radiotherapy is desirable where possible. To adjust the radiation, patients were classified into one of three risk groups based on the risk of locoregional recurrence.’
In this study, the 5-year locoregional risk of recurrence in the entire group and in each risk group was less than 4%, as expected. It therefore seems safe to de-escalate locoregional radiotherapy based on the risk of locoregional recurrence in patients with cT1-2N1 breast cancer treated with neoadjuvant chemotherapy.
Research leader Liesbeth Boersma, radiotherapist-oncologist Maastro: ‘In patients with a low or moderate risk of a locoregional recurrence, radiotherapy may be reduced more often in the future, which should of course lead to a better quality of life. Future studies and ongoing studies will clarify how and whether radiotherapy can be further adapted to individual risks.’
Reference: Sabine R de Wild, Linda de Munck, Janine M Simons, Janneke Verloop, Thijs van Dalen, Paula HM, Elkhuizen, Ruud MA Houben, A Elise van Leeuwen, Sabine C Linn, Ruud M Pijnappel, Philip MP, Poortmans, Luc JA Strobbe , Jelle Wesseling, Adri C Voogd, Liesbeth J Boersma. De-escalation of Radiotherapy After Primary CHEMotherapy in cT1-2N1 breast cancer (RAPCHEM; BOOG 2010-03): 5-year follow-up results of a Dutch, prospective, registry study. The Lancet Oncology. 2022
The article is available at The Lancet Oncology as of August 8, 11:30 p.m.: https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(22)00482-X/fulltext