[Why radiation for the postmastectomy patient?]

We can identify a subgroup of patients with a high risk of loco-regional relapse after mastectomy. When those patients are irradiated, their absolute loco-regional relapse risk drops for more than 10% with a relative risk reduction of 66% (p < 0.0001). The severe complication rate is below 1%. With earlier radiotherapy techniques, there was an excess in long term cardiac mortality among irradiated patients. Even if the breast specific survival was improved with radiotherapy, the overall survival was not better. Three recent randomised trials have shown that postmastectomy radiotherapy adds 10% survival benefit to an adjuvant systemic treatment. The impact of radiotherapy on overall survival is more pronounced for less advanced tumors.