Receipt of vaginal brachytherapy is associated with improved survival in women with stage I endometrioid adenocarcinoma of the uterus: A National Cancer Data Base study

BACKGROUND: Randomized controlled trials have consistently shown that the use of postoperative radiotherapy (RT) for stage I endometrial cancer leads to a reduction in the incidence of pelvic recurrences without a corresponding reduction in overall mortality. It was hypothesized that a reduction in mortality associated with the receipt of RT could be identified in a large data set with greater statistical power. METHODS: Women with surgically staged IA or IB endometrial adenocarcinoma who were treated with total hysterectomy between 2003 and 2011 were identified in the National Cancer Data Base. Chi-square tests and multivariate logistic regression were performed to analyze factors associated with the treatment type. A survival analysis was performed with log-rank testing, Cox proportional hazards regression, and Kaplan-Meier estimates. RESULTS: A total of 44,309 eligible women were identified (33,380 at stage IA and 10,929 at stage IB): 88.4% of the women with stage IA tumors and 51.6% of the women with stage IB tumors received no RT. Older age, comorbid disease, a higher histologic grade, and a larger tumor size were independently associated with an increase in mortality. The receipt of vaginal brachytherapy (VB) was independently associated with a reduction in mortality for both stage IA disease (hazard ratio [HR], 0.81; 95% confidence interval [CI], 0.67-0.97) and stage IB disease (HR, 0.62; 95% CI, 0.51-0.74). CONCLUSIONS: Analyses of this large database support the utility of postoperative VB for many women with stage I endometrial cancer. Unfortunately, RT appears to be underused in this population. Greater adherence to consensus guidelines may lead to improved outcomes. Cancer 2016;122:3724-31.