The curative role of radiotherapy in the treatment of operable breast cancer.

The last quarter of the twentieth century has brought about sweeping changes in the loco-regional treatment of breast cancer. Randomised trials have consistently established that survival rates after conservation surgery and breast irradiation are equivalent to those observed after modified radical mastectomy [1]. Moreover, during the same period the use of mammography in asymptomatic women has led to a relative increase in small tumours, ideally suitable for breast conservation. As a consequence, the use of conservation surgery has risen progressively during the 1980s and 1990s, with a corresponding increase in the importance of breast irradiation. In addition, recent meta-analyses of randomised trials have established that breast cancer mortality can be significantly reduced by loco-regional radiotherapy (RT), and that the increased intercurrent mortality observed in older trials was caused by an excess in cardiovascular deaths, presumably avoidable, associated with the earlier techniques [2,3]. Newer trials of postmastectomy radiotherapy (PMRT) have demonstrated a clear survival improvement, without excess cardiac morbidity, leading to an increased confidence in the use of adjuvant loco-regional RT [4,5]. The extent of the swing to conservative surgery varies amongst geographical regions, depending, at least in part, on the availability of radiotherapy services. With the increasing diffusion of medical technology throughout Europe, this factor will probably assume a decreasing importance for the choice of primary breast cancer therapy. In urban areas with a high socio-economic standard, it is likely that mastectomy will come to be practised in a dwindling minority of patients. According to the Geneva Tumour Registry, the proportion of all curative breast operations that were conservative rose from 3% before 1985, to 51% in 1990, then to 67% since 1998 (Registre genevois des tumeurs, unpublished data, 2000). As a consequence, patients currently requiring mastectomy are likely to have larger tumours and positive lymph nodes, and will frequently be considered for PMRT. In such a setting, a substantial majority of primary breast cancer patients will therefore receive RT as part of their initial treatment. These changes come at a time when the prevalence of breast cancer is increasing significantly due, at least partly, to the ageing of the European population. For Geneva, an increase of more than 50% in the number of new breast cancer cases is projected for the period between 2000 and 2010 (Registre genevois des tumeurs, unpublished data, 1998). The demand for radiotherapy services required to treat breast cancer patients may thus be expected to increase substantially. Accordingly, the European Society of Mastology (EUSOMA) believes that a position paper regarding the use of RT in breast cancer is timely and useful. This document discusses the indications for adjuvant RT in operable breast cancer (clinical stages T0-3, N0-1, M0), the technical principles for its proper execution, and where possible, notions of its optimal co-ordination with other treatment modalities. As the breast cancer literature is vast, analysis was necessarily restricted to data having a high likelihood of being reliable, making every effort to draw conclusions likely to be pertinent to