The Impact of Combined Radiation and Chemotherapy on Outcome in Uterine Clear Cell Carcinoma Compared with Chemotherapy Alone

Abstract

AimsTo investigate the impact of pelvic radiation on survival in patients with uterine clear cell carcinoma (UCC) who received adjuvant chemotherapy. Materials and methodsPatients with stage I–IV UCC who had undergone surgery and chemotherapy were identified from the Surveillance, Epidemiology, and End Results (SEER) programm 2000–2009. Patients were divided into those who received only chemotherapy and those who received both chemotherapy and radiation therapy. Kaplan–Meier curves and Cox regression models were used for analysis. ResultsOf the 317 patients included, 195 (62%) were in the chemotherapy only group and 122 (38%) were in the chemotherapy and radiation therapy group. Pelvic radiation was associated with significant improvement in overall survival (median 88 versus 25 months, 5 year survival: 58% versus 33%, P<0.001) in the chemotherapy and radiation therapy group compared with the chemotherapy only group for the entire cohort. On subset analysis, chemotherapy and radiation therapy was associated with improved overall survival in late stage disease (III–IV) (5 year 54% versus 22%, P<0.001) compared with the chemotherapy only group, whereas in stage I–II UCC, there was no difference in overall survival between the chemotherapy and radiotherapy group and the chemotherapy only group (5 year 65% versus 67%, P=0.69). In multivariable analysis, pelvic radiation was associated with improved survival in patients with late stage disease (hazard ratio 0.57, 95% confidence interval 0.35–0.94, P=0.03) but not for early stage disease (hazard ratio 0.81, 95% confidence interval 0.33–2.0, P=0.65). Other significant predictors were advanced stage, positive cytology and extensive lymphadenectomy. ConclusionsRadiation was associated with significant improvement in survival in advanced stage UCC, but not in early stage UCC. These data support the beneficial role of radiation therapy in UCC, especially in patients with advanced stage disease.