[Radiosensitivity settings in breast cancer].

[Radiosensitivity settings in breast cancer]. Cancer Radiother. 2015 May 22; Authors: Lauche O, Azria D, Riou O, Charissoux M, Lemanski C, Bourgier C Abstract Breast cancers are highly radiosensitive since the risk of recurrences and of mortality after adjuvant radiotherapy following breast-conserving surgery is decreased by 15.7% and 3.8%, respectively at 10years. The total dose if irradiation also significantly increases local control: a boost of 16Gy to the tumour bed after breast-conserving surgery reduces the absolute risk of recurrence by 4% at 10years. Breast cancers are sensitive to the dose per fraction, as shown by the results from four randomized trials which compared standard irradiation (50Gy/25 fractions) with a hypofractionated scheme: no statistical difference was observed in locoregional recurrence and overall survival at 10years. The α/β ratio, which reflects the dose per fraction and is theoretically over 10Gy for tumour tissues, has been estimated between 2.2 and 4.4Gy for breast cancers. Molecular abnormalities, such as overexpression of HER1 (especially in triple negative breast cancer) and HER2, induce a higher radioresistance. In vitro studies showed that targeted therapies, which block these receptors, increase breast cancer radiosensitivity. Tumour stem cells have been identified in breast cancers and are characterized by a higher radioresistance. This radioresistance could be related to a better repair of...
Source: Cancer Radiotherapie - Category: Cancer & Oncology Authors: Tags: Cancer Radiother Source Type: research