Severe Toxicity and Provider-Reported Subjective Symptoms in Patients With Vulvar Cancer Receiving Curative-Intent Radiotherapy.

Purpose/Objective(s) Definitive or adjuvant radiotherapy (RT) for vulvar squamous cell carcinoma (VSCC) is associated with significant toxicity that can negatively impact a patient's health-related quality of life (HRQoL). Given the rarity of this disease, data on the incidence of acute and late severe toxicity as well as the real-world late-symptom burden from a modern cohort are lacking. Materials/Methods Patients with VSCC treated with adjuvant or definitive radiotherapy with curative intent from 2009-2020 within our multi-center academic medical system were retrospectively analyzed. Treatment-related acute and late (≥3 months after RT) grade 3 or greater toxicities assessed by CTCAE version 5.0 were recorded. All provider-reported subjective symptoms (PRSS) documented from the date of RT completion to the date of last follow up were recorded. Kaplan-Meier model was used to estimate one-year overall survival (OS) and progression-free survival (PFS). Results Thirty-nine patients received either definitive (n = 22, 56.4%) or adjuvant (n = 17, 43.6%) RT to a median dose of 64.4 Gy and 59.4 Gy, respectively. Five patients (3 definitive, 2 adjuvant) received a brachytherapy boost with a median total EQD2 of 84.3 Gy. Intensity-modulated or volumetric-modulated arc RT was used in 34 (87.2%) of patients, and 22 patients (56.4%) received concurrent chemotherapy. Median follow up time was 12.5 months (Q1-Q3: 2.8-31.3 months) for all patients and 14.9 months (3.8-33.2) for alive patients. Seventy-four percent of patients (FIGO Stage I; n = 10, II; n = 5, III; n = 10, IVA; n = 4) had a complete response based on clinical (n = 26) or pathologic (n = 3) criteria, including 16 treated with adjuvant RT and 13 treated with definitive RT. The 1-year estimated OS and PFS were 90.4% and 90.5%, respectively. The incidence of acute grade ≥3 toxicity was 35.9% (n = 14). Acute grade ≥3 skin toxicity was most common (n = 10, 25.6%), followed by urinary (n = 1, 2.6%), gastrointestinal (n = 1, 2.6%), hematologic (n = 1, 2.6%), and fatigue (n = 1, 2.6%). Five (12.8%) patients experienced late grade ≥3 toxicity, including 2 patients (5.1%) with grade 3 dermatologic toxicity, 2 patients (5.1%) with grade 4 skin toxicity, and 1 patient (2.6%) with grade 3 gastrointestinal toxicity. Among the 32 patients with PRSS data available, 6 (15.3%) reported dyspareunia or inability to have sexual intercourse, 5 (12.8%) noted skin discoloration or fibrosis, 11 (28.2%) reported long-term vaginal pain or irritation, and 8 (20.5%) required long-term opiate pain medication. Conclusion RT for VSCC is associated with considerable rates of severe acute and late toxicity as well as PRSS that affect both a patient's physical functioning and HRQoL. Taken together with the high rates of disease control and survival, these data argue for improved patient-reported outcome measures and investigation of therapeutic de-escalation strategies. Author Disclosure N.S. McCall: Honoraria; PrecisCA.T.Y. Eng: Stock; Amgen. J.W. Shelton: None. S. Hanasoge: None. P.R. Patel: None. A.B. Patel: Honoraria; American College of Radiology. A. McCook: None. J. Switchenko: None. T. Cole: None. N. Khanna: None. C. Han: None. A.N. Gordon: None. K. Starbuck: None. J.S. Remick: None.