Safety and tolerability of biodegradable balloon spacers in patients undergoing radiotherapy for organ-confined prostate cancer

Introduction: Radiotherapy is a common treatment for prostate cancer, and can be administered in various ways, including 3D conformal radiotherapy (3DCRT), intensity-modulated radiotherapy (IMRT) and hypo-fractionated radiation therapy. During treatment the gastrointestinal tract may be exposed to radiation and the rectal wall may be exposed to high doses of ionizing radiation, which can lead to rectal bleeding, ulcers or fistulas, and an increased risk of rectum cancer. Various strategies to minimize these complications have been developed in the last decade; one of the most promising is to use a rectal balloon to fixate the prostate gland during treatment or to inject biodegradable spacers between the prostate and rectum to reduce the rectal dose of radiation. Aim of our paper is to evaluate the safety and tolerability of spacers implantation. Materials and methods: From January 2021 to June 2022 all patients with a diagnosis of prostate cancer with unfavorable/ intermediate risk - poor prognosis and programmed hypofractionated radiation therapy were enrolled. In all patients biodegradable balloons spacers were placed posteriorly to the prostate to increase the separation between prostate and rectum. The duration of the procedure, observation time, the appearance of early and late complications and their severity (according to Charlson comorbidity index) and tolerability of the device were recorded at the time of positioning and after 10 days. Results: 25 patients were enrolled in our study. Two patients (8%) underwent acute urine retention resolved with catheterization and one patient (4%) developed a mild perineal hematoma that did not require any treatment. As regards late complications 1 patient (4%) developed hyperpyrexia (> 38°C) the day after the procedure requiring continuation of antibiotic regimen. At T1 visit we recorded no medium-high grade complications. As for the tolerability of the device, it was optimal with no perineal discomfort or alterations of bowel function. Conclusions: Biodegradable balloon spacers appears to be safe and well tolerated and its positioning does not present any technical difficulties or risks of major complications.