07 Nov Breast Cancer: Breast-Conserving Treatment With or Without Radiotherapy for Ductal in-Situ Disease
MedicalResearch.com Interview with:
Mila Donker, MD
Resident in Radiation Oncology
Study monitor EORTC 10981-22023 AMAROS trial
The Netherlands Cancer Institute – Antoni van Leeuwenhoek hospital, Plesmanlaan 121, 1066 CX Amsterdam, Netherlands
MedicalResearch.com: What are the main findings of the study?
Dr. Donker: Results of EORTC trial 10853 which were recently published in the Journal of Clinical Oncology showed that breast conserving treatment combined with radiotherapy reduces the risk of local recurrence in women with ductal carcinoma in situ (DCIS).
Between 1986 and 1996, this phase III EORTC trial 10853 randomized 1010 women with complete local excision of DCIS to no further treatment (503 patients) or radiotherapy (507 patients). The risk of any local recurrence was found to be reduced by 48% in the patients who also received radiotherapy. The 15-year local recurrence-free rate was 69% for the group of patients receiving breast conserving surgery alone, but this increased to 82% for the group of patients who also received radiotherapy, and the 15-year invasive local recurrence-free rate was 84% versus 90%, respectively.
The differences observed in local recurrence did not lead to differences in breast cancer specific survival or overall survival, but patients with invasive local recurrence did have a significantly worse breast cancer specific survival (HR: 17.7) as well as overall survival (HR: 5.2) than those who did not recur. Thus, an invasive recurrence resulted in a worse prognosis.
A lower overall salvage mastectomy rate after a local recurrence was observed in the group of patients who also received radiotherapy, 13%, than in those patients who just received breast conserving surgery, 19%. Thus, radiotherapy after breast-conserving surgery for DCIS resulted in an overall lower percentage of patients who were treated with a salvage mastectomy.
MedicalResearch.com: Were any of the findings unexpected?
Dr. Donker: Following the introduction of radiotherapy combined with breast-conserving surgery for operable invasive breast cancer in the 1980’s, several trials were launched to investigate the addition of radiotherapy to local excision of DCIS. These trials showed, as well as a previous update of the EORTC trial 10853, that radiotherapy reduced both the risk of DCIS and invasive local recurrences, without affecting the overall survival. However, little was known about the treatment of patients who developed a local invasive recurrence.
Mastectomy has been historically the standard local treatment when a local recurrence occurs after breast-conserving treatment that includes radiotherapy. One of the arguments in favour of omitting radiotherapy after excision of the primary DCIS-lesion is the hypothetical ability to perform salvage breast-conservative treatment including radiotherapy when a local recurrence occurs. The finding that the group of patients treated with radiotherapy for their initial treatment had a overall lower risk on a salvage mastectomy after a recurrence, was therefore unexpected.
MedicalResearch.com: What should clinicians and patients take away from your report?
Dr. Donker: Adjuvant radiotherapy after a local excision for DCIS reduced the incidence of both in situ and invasive local recurrences by a factor 2. A subgroup of patients who would not benefit from adjuvant radiotherapy could not be identified in this study. Furthermore, due to the decreased risk on local recurrences, adjuvant radiotherapy in the initial treatment resulted in an overall a lower risk of a salvage mastectomy as treatment for a local recurrence. Although the reduction in local recurrences due to adjuvant radiotherapy did not affect the overall survival, an invasive local recurrence resulted in a significant worse survival compared to patients without a local recurrence. Therefore the prevention of a local recurrence remains important in this group of patients.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Dr. Donker: Survival after DCIS is good, with breast cancer specific survival rates of about 95% at 10 years. Therefore the question rises whether radiotherapy should be a standard part of the conservative treatment or whether this is overtreatment for certain patients. Long-term follow-up of large clinical trials could help answering this question. With the available data from this current trial it was not possible to identify subgroups of patients with such an a priori low risk on an invasive local recurrence, that radiotherapy could be omitted. Future research including high number of patients with long-term follow up could help to identify which patients would not benefit from treatment with adjuvant radiotherapy.
Mila Donker, Saskia Litière, Gustavo Werutsky, Jean-Pierre Julien, Ian S. Fentiman, Roberto Agresti, Philippe Rouanet, Christine Tunon de Lara, Harry Bartelink, Nicole Duez, Emiel J.T. Rutgers, and Nina Bijker