Overview of randomized trials in high risk breast cancer patients treated with adjuvant systemic therapy with or without postmastectomy irradiation.

Postmastectomy irradiation has been analyzed in several randomized trials, usually without the presence of systemic therapy. Overview analysis of these studies has shown that, although postmastectomy irradiation generally reduces the locoregional recurrence rate by a factor of 3, this is not transferred into a general long-term survival benefit. Recently, a clinically relevant survival gain from adjuvant radiotherapy has been shown in high-risk premenopausal patients also treated with adjuvant chemotherapy. There are now 11 published trials, including more than 6000 patients, in which the effect of postmastectomy radiotherapy has been evaluated in the presence of adjuvant systemic therapy. This article reviews the available data from these trials, as well as problems in their design, sample size, inclusion criteria, quality, and extent of treatments, and length of follow-up time.