Abstract: Radiotherapy(RT)is of importance in the management of breast cancer.Over 50% of patients receive RT at some time during the treatment of their disease,equating to over 500 000 patients worldwide receiving RT each year.Unfortunately,not all the patients derive from benefit and some breast cancers are resistant to treatment,as evidenced by distant metastatic spread and local recurrence.Prediction of individual responses to RT may allow a stratified approach to this treatment permitting those patients with radio-resistant tumours to receive higher doses of RT.Also,for those patients unlikely to respond at all,it would prevent from harmful side effects occurring for no therapeutic gain.More selective targeting would better direct National Health Service resources,ease the burden on heavily used treatment RT machines and reduce the economic cost of cancer treatment.Unfortunately,there are no robust and validated biomarkers for predicting RT outcome.We review the available literatures to determine whether classification of breast cancers according to their molecular subtypes may be used to predict successful response to increase morbidity from RT.

Key words: Radiotherapy, Breast cancer, Molecular subtypes, Radiosensitising