The association of vagina equivalent dose in 2Gy fraction (EQD2) to late vagina toxicity in patients of cervical cancer treated with WPRT plus IGABT

Abstract

To evaluate the associations of vaginal dose parameters and incidence of vaginal stenosis in patients with cervical cancer treated with image-guided brachytherapy (IGBT). Fifty-four patients with cervical cancer treated with IGBT were included. The vagina contouring was done on previously treated CT images and the vaginal dose points were marked. The cumulative dose in EQD2 from EBRT and IGBT was calculated for both aspects and the vaginal toxicity was evaluated. At median follow-up time of 18.5 months, grade 2 or higher vaginal stenosis was observed in 24% of patients. On univariate analysis, parameters that were associated with ≥ grade 2 vaginal stenosis were age, mean dose of lateral 5 mm vagina, dose at PIBS-2 cm, mid vaginal D0 .03cc, mid vagina D1cc, lower vagina D0.03cc, lower vagina D0.1cc, lower vagina D1cc and lower vagina D2cc. On multivariate analysis, the significant parameters were age > 68.5 years old (P = 0.038), mean dose of lateral 5-mm (P = 0.034), and dose at PIBS-2 cm (P = 0.042). Age > 68.5 years old, mean dose of lateral 5 mm vagina and dose at PIBS-2 cm were associated with grade 2 or higher vaginal stenosis.