Dados do Resumo

Título

Evaluation of Dosimetric Benefits from Rectal Hydrogel Spacers for Prostate Cancer Radiotherapy

Descrição da inciativa

Prostate cancer (PCa) is the second most commonly diagnosed male malignancy in the Western world. Increasing doses of Radiation given to the prostate improves biochemical disease-free survival, but it is necessary to avoid acute and long-term toxicities to improve QOL.
Basically, the hydrogel is allocated between the prostate and the rectum to separate these two structures and to reduce the dose of radiation received by the rectum, with minimum discomfort. After a variable period of 3 to 4 months the gel is reabsorbed
Through a prospective study of 8 patients with localized prostate cancer, treated at AC Camargo Cancer Center, Sao Paulo, Brazil, we evaluated the discomfort ("Visual Analog Scale") associated to conscious sedation (midazolan plus fentanila) and local perineal anesthesia (lidocaine 2%), plus the dosimetric impact on rectal dose distribution, comparing data pre and post hydrogel spacer injection,

Impacto e resultados

The median age of patients were 66 years old (range 54-82), median VAS was 2 (range 0-4). The median PTV volume was 85.8 cc (range 39.1-90.5), median decreased rectal dose to 1%, 2%, 5% and 10% volume, were: 17.4%, 21.8%, 22.5% and 18.5%.
No patient presented complaints or other symptoms after hydrogel injection.
One patient in the second course of radiation (salvage) presented a perineal abscess, treated with local drainage and antibiotics, with complete resolution.
None of the 8 patients had > acute Grade 1 diarrhea and no late rectal toxicities were seen.
The use of polyethylene glycol-based spacer between the rectum and the prostate is already approved to reduce potential rectal toxicity in prostate radiation in the USA, Europe, and Asia. In 2022, it had the clearance of ANVISA in Brazil.
Hydrogel spacers reduced radiation dose given to the rectum ranging from 17.4% to 22.5%, resulting in decreased acute Grade 1 or more diarrhea and late Grade ≥2 rectal toxicities.
We conclude that rectal hydrogel spacers are an option for all patients undergoing external beam radttherapy, temporary or permanent brachytherapy, and, specially to those referred for salvage radiotherapy.