The impact of surgical and pathological findings on radiotherapy of early breast cancer

Abstract

Treatments results in breast conserving therapy show considerable variation with local breast control rates from 1 to 13 % at 5 years of follow-up. This wide variation and reports on prognostic factors (e.g. age, extensive ductal carcinoma in situ component and margin involvement) having an adverse effect on local control raise questions about the safety of this treatment. An attempt is made to identify surgical and pathological factors which make modifications in the radiotherapeutic treatment necessary in order to reach the perfect balance between good local control and optimal cosmetic results. For this purpose, the literature is reviewed including three randomized trials on this subject (Milan, NSABP-06 and EORTC 10801) and those studies providing sufficient data on most of the mentioned prognostic factors. Looking at the treatment characteristics of the above mentioned studies, a considerable variation is observed with regard to surgical margins, the boost dose and the application of adjuvant systemic treatment. Microscopic margin evaluation and identification of extensive in situ component (EIC) is performed in about half of these studies and the implications of these findings are very different. Although a number of authors perform multivariate analyses, this is rarely done on a complete set of variables. This results in different treatment results and conflicting data on prognostic factors. There is no agreement on one single prognostic factor and best results in terms of local control are seen in those centres combining a very wide excision with a moderate boost or a less wide excision with a high boost. Both of these approaches are likely to result in less acceptable cosmesis and are unnecessarily aggressive in the majority of the patients. The incidence and volume of residual breast tumour can be estimated after careful pathologic evaluation of the tumour specimen and information provided by the surgeon with special attention to the preoperative mammography. Treatment can be tailored for each individual patient providing consultation between surgeon, pathologist and radiotherapist.