ESTRO 2025 - Abstract Book

S73

Invited Speaker

ESTRO 2025

When considering breast-conserving therapy (BCT) versus mastectomy for patients without a BRCA1/2 mutation, early randomized clinical trials have demonstrated that BCT is equivalent to mastectomy in overall survival and breast cancer–specific survival among patients with early-stage breast cancer. Even more, population and registries studies have showed that BCT is associated with better overall survival compared to mastectomy in early-stage breast cancer. The incorporation of oncoplastic techniques to the surgical armamentarium have reduced the need for mastectomy in scenarios where mastectomy was the only option some years ago, making the surgical options wider, and at the same time, more challenging. Approximately, 5–10% of breast cancer cases are hereditary. BRCA1 and BRCA2 account for 80% of the highly penetrant inherited breast cancer cases. The surgical treatment of breast cancer patients with a genetic germline variant is also complicated. These patients carry the dilemma of a cancer diagnosis and a hereditary mutation that involves other higher risks of other cancers as well as changes in their chances of developing second primary breast cancers in their lifetime. Nipple skin sparing mastectomy has shown to be oncologycally safe in this population. Also some guidelines recommend that “germline BRCA status should not preclude a patient with newly diagnosed breast cancer otherwise eligible for BCT from receiving BCT”. There are studies that have shown that survival outcomes following breast conservative surgery is comparable to mastectomy in BRCA carriers, although the local recurrence is increased. Some patients may opt for BCT assuming a potentially higher future risk of ipsilateral (around 30% at 20 years) and contralateral breast cancer events (around 50% in the following 20 years).. Patient counselling should be tailored to incorporate all the findings as well as the follow- up depending on which surgical technique is observed. The decision-making process is also affected by family experiences with breast cancer and pathogenic variants, so these patients have already a high psychologically burden. In cases of mastectomy, although the advantages of breast reconstruction have been widely recognized, there is plenty of options to discuss that requires different approaches as type of reconstruction, adjuvant radiation therapy, possible complications, changes in sensation, and expectations for longer follow up. Whether it is a breast cancer diagnosis with or without pathogenic variants, discussions about patient expectations, body image, timing, potential complications, recovery times and further treatments, need to be included. In the upcoming years, as the indication for germline testing in breast cancer are expanding, more patients will be facing the diagnosis of a breast cancer and a pathogenic variant in BRCA1/2. And it will not only impact on the surgical decisions, but also it will impact in systemic treatment options, including targeted therapies (like PARP inhibitors), which have been shown to reduce recurrence among patients with BRCA1 or BRCA2 germline variant– associated early breast cancer. Breast cancer surgeons are now dealing with the paradox of seeing an increased number of patients with low/moderate risks deciding to undergo bilateral mastectomies and, on the other hand, high risk breast cancer patients with pathogenic variants considering having BCT. Breast cancer patients and breast surgeons, along with the multidisciplinary decisions, should undergo through the shared-decision making when the patients have all the information and the time to consultation and the trained breast surgeons have clearly discussed the clinical evidence. All this process will be crucial in determining the best surgical options based on both medical indications and patient’s individual goals.

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Speaker Abstracts The impact of BRCA-carriership on indications for RT Icro Meattini Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy. Radiation Oncology & Breast Unit, Azienda Ospedaliero Universitaria Careggi, Florence, Italy Abstract: Breast cancer associated with BRCA1 and BRCA2 mutations exhibits distinct biological and clinical characteristics compared to sporadic breast cancer. These mutations, involved in DNA repair via homologous recombination, lead