Surgical treatment for women with breast cancer: do randomized clinical trials represent current medical practices?

Randomized clinical trials have not shown survival differences between breast cancer patients who undergo breast-conserving surgery and those who undergo modified radical mastectomy (MRM). Recent studies however, have suggested that these randomized clinical trials findings may not be representative of the entire population or the nature of current patient care. A retrospective analysis of female invasive breast cancer patients who underwent surgery in the Surveillance, Epidemiology, and End Results database (1990-2003) was performed. Survival was compared amongst women who underwent partial mastectomy, partial mastectomy plus radiation (PMR), or MRM. Cox proportional hazards regressions were used to investigate the impact of method of treatment upon survival, after adjusting for patient and tumor characteristics. A total of 218,043 patients, mean age 62 years, were identified. MRM accounted for 51.5 per cent of the study population whereas PMR accounted for 34.9 per cent. On multivariate analyses, significant improvement was observed in patient survival associated with PMR when compared with MRM patients (hazard ratio = 0.71, 95% confidence interval = 0.67-0.74, P < 0.001). This population-based study suggests that there is a survival benefit for women undergoing PMR in the treatment of breast cancer.