ESTRO meets Asia 2024 - Abstract Book

S151

Interdisciplinary – Gynaecological

ESTRO meets Asia 2024

fractions. The dose was prescribed to point A based on ICRU 89 recommendations. Three vaginal reference points (PIBS, PIBS+2, PIBS-2) were documented in both the CRT and ICBT, and Total equal-effective dose EQD2 α/β=3 of PIBS, PIBS plus 2, and PIBS minus 2 were calculated. Post-treatment, patients were followed every three months by clinical examination, and four primary objectives like discharge per vagina (PV), bleeding per vagina, stenosis, and shortening of the vagina, were documented. Grading of Vaginal toxicity was done as per LENT-SOMA scoring.

Results:

The median follow-up was 8 months (4-17 months). 35.5% of the patients were pre-menopausal, and 64.5% were post-menopausal women, respectively. 58% of patients developed any grade of vaginal toxicity at their median follow-up of 6 months post-treatment. 29% had grade 1 vaginal toxicity, 16.1% had grade 2 vaginal toxicity, and 12.9% had grade 3 vaginal toxicity. Doses at ICBT-PIBS+2 and ICBT-PIBS were high and positively correlated with vaginal toxicity grading (r-0.68, p=0.001 & r-0.56, p-0.001). ICBT-PIBS-2 was moderately and positively correlated (r-0.49, p-0.006).

Conclusion:

Study indicates that the PIBS+2, PIBS, and PIBS-2 point doses at the vagina during brachytherapy can be a valuable predictor for vaginal toxicities and can be used as dose constraints for grading. However, further research with a more extended cohort is needed to grade the toxicity (0-3) for the cutoff point dose.

Keywords: BRACHYTHERAPY, POINT DOSE, VAGINAL TOXICITY

References:

1. Kirchheiner K, Nout RA, Lindegaard JC, Haie-Meder C, Mahantshetty U, Segedin B, et al. Dose–effect relationship and risk factors for vaginal stenosis after definitive radio(chemo)therapy with image-guided brachytherapy for locally advanced cervical cancer in the EMBRACE study. Radiother Oncol. 2016 Jan;118(1):160– 6. 2. Morris L, Do V, Chard J, Brand A. Radiation-induced vaginal stenosis: current perspectives. Int J Womens Health. 2017 May;Volume 9:273–9. 3. Westerveld H, Pötter R, Berger D, Dankulchai P, Dörr W, Sora MC, et al. Vaginal dose point reporting in cervical cancer patients treated with combined 2D/3D external beam radiotherapy and 2D/3D brachytherapy. Radiother Oncol. 2013 Apr;107(1):99–105.