Impact of sex on the prognosis of patients with esophageal squamous cell cancer underwent definitive radiotherapy: a propensity score-matched analysis.

Background: The impact of sex on prognosis of patients with esophageal squamous cell cancer (ESCC) who underwent definitive radiotherapy remained unclear. The present study aimed to determine the impact of sex on the prognosis of patients with ESCC underwent definitive radiotherapy.

Methods: Between January 2009 and December 2015, patients with ESCC underwent definitive radiotherapy in Shantou Central Hospital were included in this study. The Progression-free survival (PFS) and overall survival (OS) rates were estimated using the Kaplan-Meier method. The PFS and OS were compared between female and male patients. The Cox regression model was used to identify prognostic factors. Propensity score-matched analysis was performed to balance baseline characteristics between female and male patients.

Results: A total of 683 ESCC patients treated with definitive radiotherapy were included, with 497 male and 186 female patients. In the whole cohort, female patients had a significantly longer median PFS (14.0 months vs 10.6 months, P = 0.0001, HR = 0.688, 95% CI, 0.567-0.836) and OS (20.8 months vs 15.9 months, P = 0.0005, HR = 0.702, 95% CI, 0.575-0.857). In the matched cohort, female patients still had a significantly longer median PFS (13.5 months vs 11.6 months) and OS (19.6 months vs 16.1 months). Multivariate analysis showed that sex was an independent prognostic factor for PFS (HR = 0.746, 95% CI, 0.611-0.910, P = 0.004) and OS (HR = 0.755, 95% CI, 0.615-0.926, P = 0.007).

Conclusions: This present study indicated that sex was an independent prognostic factor in Chinese patients with ESCC underwent definitive radiotherapy, with better survival outcome for women than men. Efforts should be made to investigate the underlying biological mechanism.