To estimate and compare the vaginal doses in terms of posterior inferior border of symphysis (PIBS) points such as PIBS, PIBS+2, PIBS-2, and vaginal reference length (VRL) for patients of cancer of cervix (CC) treated with intracavitary brachytherapy (ICBT) using Fletcher Williamson applicator (FW) and interstitial brachytherapy (ISBT) using Martinez Universal Perineal Interstitial Template (MUPIT).

Treatment plans of a total of 36 consecutive CC patients, who underwent ICBT and ISBT with FW and MUPIT respectively, were retrospectively included in the study. The 3D treatment planning for all the patients had been performed on computed tomography (CT) images. The median prescription dose delivered by high dose rate brachytherapy was 6 Gy per fraction. PIBS point doses were estimated for each plan and analysed with OriginPro2024b graphing and analysis software.

The Mann Whitney test showed statistically significant differences in vaginal doses in terms of percentage of prescription dose (PD) between ICRT and ISBT. Spearman’s rank correlation coefficient (ρ) values indicated that vaginal wall dose and VRL were strongly correlated for FW applicator as compared to MUPIT applicator.

Vaginal wall doses in terms of percentage of the PD with MUPIT applicator were found higher than with the FW applicator. Our results suggested that estimation of vaginal doses for each patient was necessary during planning phase in order to avoid the late toxicities.