Post-surgery radiation in early breast cancer: survival analysis of registry data.
OBJECTIVE
Overviews of randomized trials have shown a small survival advantage with post-surgery radiation in early breast cancer. The present study attempts to extend this observation through a systematic analysis of population data.


METHODS
This retrospective cohort study used the Surveillance, Epidemiology, and End Results (SEER) data on 83,776 women with breast cancer 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 patients (hazard ratio 0.757; 95% confidence interval 0.709-0.809; using total mastectomy without radiation as reference) and in node positive patients (hazard ratio 0.777; 0.717-0.842), and after total mastectomy in node positive patients (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 patients. Without radiation, breast-conserving surgery in node negative patients was associated with an increased hazard ratio (1.167; 1.036-1.314); a similar increase was not observed in node positive patients (hazard ratio 1.011; 0.884-1.155). In all cases, the best survival rates were found with combined breast-conserving surgery and radiation.


CONCLUSIONS
The available data indicate that post-surgery radiation provides a survival advantage irrespective of the type of surgery in node positive patients. Likewise, survival advantage was observed with post-surgery radiation and breast-conserving procedure in node negative patients.
Vinh-Hung
Vincent
V
Oncologisch Centrum, AZ-VUB, 101 Laarbeeklaan, B-1090 Jette, Belgium.
Burzykowski
Tomasz
T
Van de Steene
Jan
J
Storme
Guy
G
Soete
Guy
G
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000401:mortality* / Q000532:radiotherapy* / Q000601:surgery; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008408:Mastectomy / Q000706:statistics & numerical data; D015412:Mastectomy, Segmental / Q000706:statistics & numerical data; D008875:Middle Aged; D016016:Proportional Hazards Models; D018714:Radiotherapy, Adjuvant; D016032:Randomized Controlled Trials as Topic; D012042:Registries; D012189:Retrospective Studies; D018426:SEER Program; D016019:Survival Analysis