Primary radiation therapy for squamous cell vulvar cancer: a survivor analyis

Objectives: To compare overall survival, progression-free survival, and complication rate for women with squamous cell cancer of the vulva treated with curative intent radiation therapy compared to primary surgery. Methods: Retrospective cohort study of Kaiser Permanente Northern California (KPNC) members diagnosed with invasive squamous cell carcinoma of the vulva between 2008-2018 who were treated with either primary surgery (PS) or primary radiation therapy (PRT). Additional analyses were included for patients who underwent surgery alone (PS alone) vs surgery with adjuvant radiation (PS+RT). Exclusion criteria were synchronous primary cancer, palliative treatment, and lapse of KPNC membership during primary therapy. Women were identified using an internal cancer registry and variables were extracted through chart review. Bivariate analysis was completed using Kaplan Meier curves and Chi-square tests to compare 1- and 3-year overall and progression-free survival. Multivariable Cox proportional hazards regression adjusted for age, stage (FIGO 2009), Charlson comorbidity index, and smoking status. Results: 202 women were included in the analysis. Median follow-up was 3.3 years. 59 women (29.2%) underwent PRT, of whom 47 (79.7%) received concurrent chemotherapy. 143 women (70.8%) underwent PS, of whom 33 (23.1%) received adjuvant radiation with or without chemotherapy. 83.0% of PRT patients were stage II-IV, whereas 77.6% of PS patients were stage I (p Download : Download high-res image (93KB) Download : Download full-size image Conclusions: Women with vulvar cancer treated with PRT at a large, managed care organization over a 10-year period were higher stage and had worse 1- and 3-year overall survival than women treated with PS, although survival was not significantly different when adjusting for stage. Women requiring adjuvant radiation following PS had similar 1- and 3-year survival to patients who underwent PRT. Overall complication rate was highest in women who received PS+RT, with the rate of lymphedema double that of PS alone and quadruple that of PRT. These data suggest that PRT may be an acceptable alternative to PS in women who have a high likelihood of need for adjuvant therapy.