Integrated breast conservation and intraoperative radiation therapy

Abstract

The introduction of innovative radiotherapy approaches for early breast cancer patients is rapidly changing the radiation oncologists' attitude and their expectations to obtain a good local control while decreasing morbidity therefore improving patient's quality of life. Intraoperative radiotherapy is a very attractive treatment modality in the multidisciplinary approach to breast conservation as is testified by the rapidly growing number of patients accrued in numerous studies all over Europe since 2000. A major advantage of intraoperative radiotherapy in breast cancer treatment is the administration of a large dose of radiation directly to the tumour bed, avoiding the possible geographic miss. Accurate localization and precise definition of the tumour bed volume is essential to achieve maximal efficacy in terms of local control while minimizing unnecessary damage to the normal breast tissue. Intraoperative radiotherapy reduces radiation exposure of the skin, lung, heart and normal subcutaneous tissues thus contributing to the low incidence of side effects and the generally excellent cosmetic results. Compared to other intraoperative techniques, the superiority of intraoperative radiotherapy appears to be the high homogeneity of dose distribution. The linear quadratic model used to calculate the biologic equivalent dose of intraoperative radiotherapy treatments for both tumour and normal tissue effects, is not considered totally reliable for large dose per fraction. The main concern is the potential increase in severe late side effects. Conversely, we expect an enhanced local control due to the radiobiologic efficacy of a large single dose delivered soon after tumour excision, with an immediate cell killing effect over any potential microscopic disease. The advantage of shortening the overall treatment time is that it avoids any delay in the administration of chemotherapy. The safety of intraoperative radiotherapy as a treatment modality in the context of breast conservation has been proved but conclusive data on local control and survival are expected from long term results of the ongoing studies.