The optimal overall treatment time (OTT) from radical surgery to the end of adjuvant radiation therapy for some squamous cell carcinomas has been found to impact treatment outcomes. This study aims to identify the impact of OTT on overall survival (OS) for women with completely resected, node-positive squamous cell carcinomas of the vulva.

The National Cancer Data Base was queried for women with surgically resected, node-positive vulvar squamous cell carcinomas between 2004 and 2016 who were treated with adjuvant radiation therapy. Kaplan-Meier analysis with log-rank test and Cox proportional hazards tests were utilized for OS calculations.

A total of 1500 women met inclusion criteria. The median OTT was 104 days. Shorter OTT was associated with age, facility volume, private insurance, and duration of post-operative hospitalization. Median OS with OTT ≤ 104 days was 56.1 months vs 45.4 months if ≥105 days (p = 0.015). On multivariable Cox analysis, OTT was independently associated with an increased risk of death of 0.4% per additional day (95%CI 1.001-1.007, p = 0.003), as were age at diagnosis (HR 1.031 [95%CI 1.024-1.037], p < 0.001), number of nodes positive (HR 1.031 [95%CI 1.024-1.037], p = 0.006), the use of concurrent chemotherapy (HR 0.815 [95%CI 0.693-0.960], p = 0.014) and increasing pT/pN stage. After propensity adjustment for factors predicting a shorter OTT, OTT continued to be associated with an increased risk of death per additional day (HR 1.004 [95%CI 1.001-1.007], p = 0.007).

Overall treatment time is an independent risk factor for death in women being treated with adjuvant radiation therapy following complete resection of node-positive squamous cell carcinoma of the vulva.