Radiation treatment related factors influencing outcome in vulvar cancer patients.

The objective of this research is to identify the impact of radiation treatment factors on survival in vulvar cancer patients. We performed a follow-up study on 60 women with squamous cell carcinoma of the vulva treated at the Department of Radiotherapy of the University of Ulm from 1980 to 1997. The follow-up time ranged from 0.5 to 17 years (mean 6.5 years). The irradiated volume included vulva and regional lymph nodes. The influence of treatment factors (tumor resection versus no tumor resection, treatment time, dose) on overall and disease-free survival was examined. In addition, applied doses were corrected for treatment time using the extended alpha/beta-model for calculating the biologically effective doses. The applied dose was 48.1 +/- 13.2 Gy (median: 50 Gy). Treatment time was 40.4 +/- 19.4 days (median: 38 days). 34/60 patients underwent surgery with complete resection of macroscopic tumor. 26 of 60 patients were resected incompletely or only a biopsy was taken. In univariate analysis prognostic factors influencing overall and disease-free survival were, along with T- and N-stage, treatment time, and biologically effective dose. In multivariate analysis, biologically effective dose was the only significant factor. We conclude that biologically effective dose and treatment time are important treatment factors influencing overall and disease-free survival vulvar cancer patients.