ABSTRACT
A meta-analysis was done of 10-year and 20-year results from 40 unconfounded randomized trials of radiotherapy for early breast cancer with central review of 20 000 individual patients’ data on recurrence and cause-specific mortality. Radiotherapy followed various types of surgery (total mastectomy, mastectomy with axillary surgery, and breast conserving surgery), but overall reduced local recurrence by two-thirds (27% vs. 9% at 10 years). In aggregate, radiotherapy was associated with improved breast cancer mortality and increased non-breast cancer mortality (chiefly due to ‘vascular’ causes). The overall 20-year survival rate slightly favoured radiotherapy (37% vs. 36%). There was improved breast cancer mortality and less non-breast mortality in more recent trials, in larger trials and in trials using systemic therapy compared respectively to older trials, smaller trials and trials not using systemic therapy.
