Advances in rectal protection technique in prostate cancer radiotherapy / 中华放射肿瘤学杂志

Radiation therapy (RT) is a well-established and widely used treatment modality for prostate cancer. As prostate-rectum proximity contributes to rectal toxicity, there is growing interest in rectal protection. Technical advances have enabled the reduction of rectal injury. To improve the safety of prostate cancer radiotherapy and minimize the rectal toxicity of irradiation, the advances in rectal protection technique during prostate cancer radiotherapy, including technical advances of radiation therapy, image-guided radiotherapy, application of endorectal balloons, and use of rectum spacers, were reviewed, aiming to provide reference for improving the safety of prostate cancer radiotherapy and alleviating rectal radiation injury.

Clinical application and safety evaluation of injectable cross-linked sodium hyaluronate isolation gel in radical hypofractionated radiation therapy for prostate cancer / 中华放射肿瘤学杂志

Objective:To evaluate the safety and feasibility of applying injectable cross-linked sodium hyaluronate isolation gel in radical hypofractionated radiation therapy for prostate cancer.Methods:In this prospective study, patients at Beijing Hospital who were pathologically diagnosed with clinical stage T 1-2N 0M 0 prostatic acinar adenocarcinoma by puncture and underwent radical radiation therapy were included. All patients received ultrasound-guided cross-linked sodium hyaluronate isolation gel injection and image-guided intensity-modulated radiation therapy (IG-IMRT). The prescription dose was moderately hypofractionated, with a prescription dose of 60 Gy in 20 fractions for 5 times a week, once daily, which was delivered to 95% of the planning target volume (PTV) of prostate and seminal vesicle. Analyze the prostate rectal spacing (PRS) at the baseline, on the day of injection, during the radiotherapy, 1 month and 3 months after radiotherapy, changes in rectal volume before and after injection, and incidence of rectum-related side effects. The changes in all indexes before and after injection were analyzed by using t-test. Results:A total of 13 patients were enrolled from March 2022 to February 2023. The isolation gel maintained morphologic stability without significant spatial changes during radiotherapy, and the mid-prostate had the best effect, with PRS up to 1 cm. At 3 months after radiotherapy, the isolation gel was seen to decreased in volume with a certain absorptive capacity. The irradiated volume of rectum was decreased significantly in all patients after gel injection, and the mean volumes of rectal V 60 Gy , V 50 Gy , V 30 Gy , and V 20 Gy before and after injection were 1.923% vs. 0.280%, 10.255% vs. 3.172%, 29.602% vs. 18.800%, and 49.452% vs. 40.259% (all P<0.005). The average values (range) of rectal V 60 Gy , V 50 Gy , V 30 Gy , V 20 Gy decreases were 84.9%( 29% - 100%), 69.6%(27%-100%), 36.3%(0%-75%), and 17.8%(0%-50%), respectively. No grade 3-4 side effects occurred in all patients, and there were no common grade 1-2 rectal side effects such as diarrhea, rectal bleeding, proctitis and anal pain, etc. Only one patient developed grade 1 constipation during radiotherapy. Conclusion:Injection of Chinese made cross-linked sodium hyaluronate isolation gel can significantly reduce the irradiated volume of rectum and the incidence of rectal toxicities in prostate cancer patients undergoing radical radiotherapy.