Effects of surgery on the prognosis of patients with locally advanced vulva cancer: A retrospective study of the SEER database and a Chinese multicentre registry.

5616 Background: Vulva cancer is a rare gynecologic oncology, and lacks uniform recommendations in current guidelines, especially for locally advanced cases. This study seeks to explore prognostic factors and optimize treatment strategies for vulva cancer. Methods: This multicenter, cross-ethnic retrospective study collected patient data from 2003–2023 in the China Multi-center Registry and from 2004–2021 in the SEER database. Only pathologically confirmed cases of vulva cancer were included in the analysis. Patients lost to follow-up, under 20 years of age, were excluded. Survival outcomes were compared using Kaplan-Meier analysis, while prognostic factors were evaluated through the Cox proportional hazards model. Baseline characteristics between groups were balanced using inverse probability of treatment weighting (IPTW). The primary endpoint of the study was overall survival. Results: A total of 19,682 patients with vulva cancer were included in the study, comprising 604 patients in the Chinese cohort and 19,078 patients in the SEER cohort. Multivariate Cox regression models (China cohort: HR=0.46,95%CI:0.33-0.64, P < 0.001; SEER cohort: HR=0.43,95%CI:0.41–0.46, P < 0.001) indicated that surgery was associated with improved prognosis. In both cohorts of patients with locally advanced vulva cancer, surgery remained a protective prognostic factor (China cohort: HR =0.43,95%CI:0.27-0.69, p < 0.001; SEER cohort: HR=0.52 ,95%CI:0.47-0.57, p < 0.001). And the protective effect of surgery in patients with locally advanced disease remained significant after IPTW (China cohort: HR= 0.38 ,95%CI:0.24-0.63, p < 0.001; SEER cohort: HR=0.50 ,95%CI:0.44–0.56, p < 0.001). Conclusions: Although guidelines recommend non-surgical treatment as the preferred approach for patients with locally advanced vulva cancer, this large-scale, multicenter, cross-ethnic retrospective study demonstrates that surgery significantly improves prognosis and offers new insights for clinical practice.