Intensity modulated radiation therapy for squamous cell carcinoma of the vulva: Treatment technique and outcomes

Abstract

Objective: The objective of this study was to present the treatment technique and evaluate clinical outcomes after intensity modulated radiation therapy (IMRT) for vulvar cancer. Methods and materials: This retrospective study included 39 patients with squamous cell carcinoma of the vulva treated with IMRT from 2005 to 2015. There were 21 patients treated with postoperative IMRT, 13 with definitive IMRT, and 5 with preoperative IMRT. Tumor staging was Federation of Gynecology and Obstetrics stage I in 6, stage II in 7, stage III in 19, and stage IV in 7 patients. Concurrent chemotherapy was administered to 14 patients. Brachytherapy was delivered in 8 patients. Results: The median follow-up was 34 months (range, 3.3-71). Median IMRT dose to patients receiving pre- or postoperative IMRT was 5040 cGy (range, 5040-6080). Median combined IMRT and brachytherapy dose to gross tumor was 7000 cGy (range, 5040-7520) in those treated with definitive RT. The 3-year locoregional control (LRC) and overall survival for those receiving postoperative RT were 89% and 67%, respectively. The 3-year LRC and overall survival for those receiving definitive IMRT were 42% and 49%, respectively. In patients receiving definitive or neoadjuvant IMRT, 69% had complete clinical response and 44% had complete pathologic response. The actuarial 3-year inguinal recurrence rate was 7%. There were no acute grade 3-4 hematological, gastrointestinal, or genitourinary toxicities. There were no late grade 3-4 gastrointestinal or genitourinary toxicities. Conclusions: IMRT for vulvar cancer is associated with high rates of LRC in the postoperative setting and limited radiation-related toxicity. Durable LRC of disease after definitive IMRT remains challenging, and several refinements to our treatment technique are suggested.