Technical innovation in adjuvant radiotherapy: Evolution and evaluation of new treatments for today and tomorrow.

Recent innovations in breast cancer radiotherapy include intensity modulated radiotherapy, brachytherapy and intraoperative radiotherapy and current trials are seeking to evaluate their value in optimizing local control while maintaining cosmetic effects. Future clinical dividends in local control and survival may come from the identification of molecular signatures of breast cancer radiosensitivity, the development of predictive signatures and identification of immunohistochemical markers of risk of local recurrence. The importance of tumour heterogeneity is being increasingly recognized as an important factor in determining radiotherapy response and an improved understanding of the biology of the tumour microenvironment may identify targets that allow enhanced radiosensitisation or reversal of radioresistance when inhibited. This review describes recent developments in these areas.