This phase II trial studies the effect of rectal spacer hydrogel before radiation therapy in reducing radiation dose to the rectum in patients with prostate cancer. Rectal spacer hydrogen is a soft gel material used to create a space between the rectum and prostate during radiation treatment. The rectal spacer gel is made up of 90% water and 10% polyethylene glycol and is injected as a liquid through a needle inserted between the rectum and prostate. It stays in place for about 3 months and is naturally absorbed into the body and removed through urine in about 6 months. By pushing the prostate further from the rectum with the hydrogel, it may help spare the rectum from receiving radiation during standard of care stereotactic body radiation therapy and brachytherapy treatment.
Study sponsor and potential other locations can be found on ClinicalTrials.gov for NCT05224869.
PRIMARY OBJECTIVE:
I. To evaluate whether using a rectal spacer prior to initiating radiation therapy can increase the proportion of patients meeting the institutional goal of volume of the rectum receiving at least 100% of the prescribed dose (V100rectum) < 0.75 cc after brachytherapy implant.
SECONDARY OBJECTIVES:
I. To assess prostate tumor coverage and implant quality using radiation dose covering 90% of the prostate (D90prostate) and volume of the prostate receiving at least 150% of the prescribed dose (V150postate) at the time of post-implant dosimetry (PID).
II. To assess quality of life (QOL) changes using International Prostate Symptom Score (IPSS), Sexual Health Index in Men (SHIM), and Expanded Prostate Cancer Index Composite (EPIC) bowel domain scores for patients undergoing this treatment paradigm.
III. To assess anatomic distortions (such as pubic arch interference and difficulty using the brachytherapy template) using physician reporting.
IV. To assess radiographic distortions (including poor ultrasound quality) using physician reporting.
V. To assess V100rectum for the stereotactic body radiotherapy (SBRT) portion of radiation therapy (RT).
OUTLINE:
Patients undergo hydrogel rectal spacer placement on day 1. Within 1 week after hydrogel placement, patients undergo computed tomography (CT) simulation of radiation treatment planning. Within 1 week after CT simulation, patients undergo SBRT in 5 fractions. Within 2 weeks after completing SBRT, patients undergo brachytherapy. Within one month after brachytherapy, patients undergo post-implant dosimetry scan.
After completion of study treatment, patients are followed up at 3, 6, 12, 18, and 24 months.
Trial PhasePhase II
Trial Typesupportive care
Lead OrganizationIcahn School of Medicine at Mount Sinai
Principal InvestigatorRichard Glenn Stock
