Brachytherapy improves survival in primary vaginal cancer

Abstract

Purpose: Prospective, randomized data does not exist to guide treatment in primary vaginal cancer (PVC). We evaluated the impact of brachytherapy on survival in women with PVC.

Methods and materials: Women who received radiotherapy for PVC were identified using the Surveillance, Epidemiology, and End Result database. Two retrospective cohorts were created; women who received external beam radiotherapy (EBRT) alone and those who received brachytherapy (alone or in combination of EBRT). Nearest-neighbor propensity score matching was used to balance the groups according to measured covariates. Cox proportional hazard regression modeling was used to estimate the effect of receipt of brachytherapy on survival.

Results: Two thousand five hundred seventeen vaginal cancer patients were identified. Squamous cell carcinoma made up 75% of tumors. Median overall survival (OS) for patients receiving EBRT alone was 3.6years (95% CI, 3.0-4.2years) versus 6.1years (95% CI 5.2-7.2years) for patients receiving brachytherapy (p=<0.001). Cox proportional hazard model revealed decrease risk of death among patients that received brachytherapy in the matched cohort (HR 0.77; 95% CI 0.68-0.86). Brachytherapy reduced risk of death among patients in all stage groups. No patient demographic or tumor variables favored the use of EBRT alone. Brachytherapy was associated with a decreased risk of death for all FIGO stages. Brachytherapy benefited patients with squamous cell carcinoma (HR 0.80; 95% CI 0.70-0.92) and adenocarcinoma (HR 0.69; 95% CI 0.49-0.95). Tumors larger than 5cm had the greatest benefit from brachytherapy (HR 0.68; 95% CI 0.50-0.91).

Conclusions: Brachytherapy should be encouraged for all suitable patients with PVC.

Keywords: Brachytherapy; High dose rate; Intracavitary; Radiation therapy; Vaginal cancer.