Morbidity related to axillary irradiation in the treatment of breast cancer

Some of the most debilitating morbidity after surgery and radiotherapy for breast cancer is related to treatment of the axilla. This includes persiste nt arm lymphoedema, impaired shoulder mobility and brachial plexopathy. Con siderable research efforts have been carried out on the radiation pathogene sis and the clinical radiobiology of these clinical endpoints, which has en abled their severity and incidence to be minimized. It is clear that the ra diation dose-response relationships For these late endpoints are very sleep . In other words, even small changes in the exact dose fractionation and ph ysical dose distribution can cause major changes in toxicity. In particular , in many treatment schedules dose fractions larger than 2 Gy have been use d without a sufficient reduction in total dose to avoid increased late effe cts. This is important, as much of the available literature reports side ef fects after suboptimal dose-fractionation schedules and inferior radiothera py techniques. Such reports are not representative of what can be achieved using modern radiotherapy. An interesting parallelism to the problems encou ntered in reviewing historical experience is found in the British breast li tigation, the current status of which is presented in this article. Further more, morbidity after radiotherapy is strongly influenced by concomitant su rgery and/or chemotherapy, and this should be allowed for when designing th e overall treatment. Apart from other therapeutic modalities, it has been s uggested that other exogenous factors have an influence on the risk of radi otherapy-related morbidity. However, patients' age and, in the case of lymp hoedema, also obesity are the only factors that have been established with some certainty. Routine adjustment of radiotherapy dose in these cases is n ot recommended. Two current developments may strengthen the role of radioth erapy in the treatment of breast cancer. Sentinel node biopsy may allow nod al staging without major surgical excision of axillary nodes and this opens the possibility for a more optimal combination of radiotherapy and surgery in the management of the axilla. With more cancers now being detected by s ystematic screening programmes, this will also increase the possibilities f or conservative management, which in most cases involves radiotherapy. In c onclusion, the improved understanding of the clinical radiobiology of late sequelae after radiotherapy allows treatment schedules and techniques to be devised that are therapeutically effective while maintaining a minimal ris k of serious, late morbidity.