Post-surgery radiation in early XXXX : survival analysis of registry data.

@entity1 @entity0
BACKGROUND AND PURPOSE: Overviews of randomized trials have shown a small survival advantage with post-surgery radiation in early @entity0 . The present study attempts to extend this observation through a systematic analysis of population data. MATERIALS AND METHODS: This retrospective cohort study used the Surveillance, Epidemiology, and End Results (SEER) data on 83,776 @entity1 with @entity0 diagnosed between 1988 and 1997, stage T1-T2, node negative or node positive. The analysis was performed using the proportional hazard models. RESULTS: Radiation was associated with a reduced mortality after breast-conserving surgery in node negative @entity1 (hazard ratio 0.757; 95% confidence interval 0.709-0.809; using total mastectomy without radiation as reference) and in node positive @entity1 (hazard ratio 0.777; 0.717-0.842), and after total mastectomy in node positive @entity1 (hazard ratio 0.885; 0.815-0.961). Radiation was associated with an increased hazard ratio of 1.271 (1.080-1.496) after total mastectomy in node negative @entity1 . Without radiation, breast-conserving surgery in node negative @entity1 was associated with an increased hazard ratio (1.167; 1.036-1.314); a similar increase was not observed in node positive @entity1 (hazard ratio 1.011; 0.884-1.155). In all cases, the best survival rates were found with combined breast-conserving surgery and radiation. CONCLUSION: The available data indicate that post-surgery radiation provides a survival advantage irrespective of the type of surgery in node positive @entity1 . Likewise, survival advantage was observed with post-surgery radiation and breast-conserving procedure in node negative @entity1 .
