Romano Edouard, Simon Raphaël, Minard-Colin Véronique, Martin Valentine, Bockel Sophie, Espenel Sophie, Fresneau Brice, Metayer Lucy, Levy Antonin, Guerin Florent, Martelli Hélène, Dumas Isabelle, Bolle Stéphanie, Deutsch Eric, Haie-Meder Christine, Chargari Cyrus
Department of Radiation Oncology, Gustave Roussy Cancer Campus, Cancer Center, University Paris Saclay Medical Faculty, Villejuif, France.
Hospices Civils de Lyon, Lyon Est University Medical Faculty, Lyon, France.
Int J Radiat Oncol Biol Phys. 2021 Jan 1;109(1):231-241. doi: 10.1016/j.ijrobp.2020.08.033. Epub 2020 Aug 14.
To examine dose-volume effect relationships for anorectal morbidity in children treated with image-guided brachytherapy for pelvic tumors.
Medical records of all consecutive children with pelvic tumors treated in our center and receiving image-guided pulsed-dose-rate brachytherapy with or without external beam radiation therapy (EBRT) between 2005 and 2019 were reviewed. The effect of the minimal doses to the most exposed 0.5 cm, 1 cm, and 2 cm of the anorectum (respectively: D, D, and D), total reference air kerma (TRAK), and volume of 100% isodose was examined for anorectal toxicities.
Seventy-eight consecutive children were included. Median age was 2.9 years (range, 0.8-14.9 years). Most of the tumors were bladder or prostate (67%) or vaginal (22%) rhabdomyosarcoma. Six patients received EBRT in addition to brachytherapy. Median follow-up was 21.3 months. At last follow-up, 30 children (38%) had experienced Common Terminology Criteria for Adverse Events version 5 grade ≥1 acute or late anorectal events: 24% had grade 1 events, 7.7% had grade 2 events, and 6.4% had grade 3 events. No toxicity greater than grade 3 was observed (eg, fistula or stricture). In univariate analysis, the D and D were significant for probability of grade 1 to 3 (P = .009 and P = .017, respectively) and grade 2 to 3 anorectal morbidity (P = .007 and P = .049, respectively). There was no significant correlation for D (P = .057 for grade 1-3; P = .407 for grade 2-3). A 10% probability (95% confidence interval, 4%-20%) for anorectal toxicity of grade 2 or greater was reached for a D = 52 Gy. The age, EBRT use, TRAK, and treated volume values were not significant.
To our knowledge, this study is the first to show a significant dose-volume effect relationships for anorectal morbidity in children undergoing treatment with brachytherapy. Integrating these data into brachytherapy treatment planning could help to optimize the therapeutic index in these young patients.
