High-dose intensity-modulated chemoradiotherapy in vulvar squamous cell carcinoma: Outcome and toxicity.

ABSTRACT

INTRODUCTION: To evaluate clinical outcomes, pattern of failure, and toxicity after high-dose intensity-modulated radiation therapy (IMRT) for advanced vulvar cancer. METHODS: In this IRB approved retrospective study, the charts of women with histologically confirmed, non-metastatic vulvar cancer consecutively treated at our institution from 2012 to 2018 were reviewed to identify patients that received high-dose IMRT with curative intent. The treatment compliance, toxicities, and patterns of failure were investigated. Actuarial local, regional and distant recurrence and survival were estimated using Kaplan-Meier method and compared using log rank test. RESULTS: Twenty-six patients were identified, 23 were unresectable, and 3 refused surgery. Fifteen patients (58%) had inguinal node metastases; 10(38%) had pelvic node metastases. Elective surgical staging of groins was performed in 9-patients. Median tumor dose was 65.4Gy. Concurrent platinum-based chemotherapy was administered in 22(84.6%) patients. Complete response (CR) was achieved in 21/26 (80.7%) patients. Five patients had persistent disease following treatment and one sustained recurrence 5-months following radiotherapy. All persistent or recurrent disease occurred inside the irradiated volume. Median follow-up was 19 months (3-52 months). Actuarial 1-year local, regional and distant controls were 72.4%, 85.4%, and 86%, respectively. One and 2-year overall survivals were 91% and 62%, respectively. Complete response at 3-months was a strong predictor for overall survival (1-yr OS 73% vs 27%, HR 7.1 (95% CI 1.2-44); p = 0.01). Lymph node metastases adversely affected overall survival (2-yr OS 49% vs. 83%, p = 0.09). Grade 3-4 late urinary and soft-tissue toxicity was seen in 5 patients. Tumor doses >66 Gy (p = 0.03) and prior pelvic radiotherapy (p = 0.002) predicted grade 3-4 toxicity. CONCLUSION: High-dose IMRT for vulvar cancer achieves high rates of local control with acceptable dose dependent long-term toxicity.