Chemotherapy, Radiation, or Combination Therapy for Stage III Uterine Cancer

Objective To compare the outcomes of women with stage III uterine cancer treated with chemotherapy alone, external beam radiation alone, and combination chemotherapy and radiation. Methods The National Cancer Database was used to identify women with stage III endometrioid, serous, and clear cell uterine cancer treated with either chemotherapy (with or without vaginal brachytherapy) alone, external beam radiation (with or without brachytherapy), or combination chemotherapy and external beam radiation (with or without vaginal brachytherapy) from 2004 to 2015. Survival was estimated using Cox proportional hazards models and adjusted survival curves after propensity score analysis using inverse probability of treatment weighting to balance the clinical and demographic characteristics between the cohorts. Results Of the 20,873 patients identified, 9,456 (45.3%) received chemotherapy alone, 2,417 (11.6%) were treated with radiation alone, and 9,000 (43.1%) received chemotherapy in combination with external beam radiation. Use of combination therapy was 33.0% in 2004, and then rose to 50.5% in 2015. The mortality of the cohort was 33.1% and median survival was 115 months. Within the cohort, combination therapy was associated with a 23% reduction in mortality (hazard ratio [HR]=0.77; 95% CI 0.73-0.80) compared with chemotherapy alone. Similar findings of decreased mortality were noted in subgroup analyses for both stage IIIA (HR=0.81; 95% CI 0.68-0.98) and stage IIIC (HR=0.79; 95% CI 0.75-0.84) tumors. Similarly, when compared with radiation alone, combination therapy was accompanied by a 19% decrease in mortality (HR=0.81; 95% CI 0.73-0.89). Combination chemoradiation was associated with decreased mortality across all of the histologic subtypes. Conclusion Among women with stage III uterine cancer, combination chemotherapy and external beam radiation is associated with decreased mortality compared with chemotherapy or radiation alone.