(UroToday.com) The 2024 American Urological Association (AUA) annual meeting featured a session on localized prostate cancer, and a presentation by Dr. Benjamin Shpeen discussing SpaceOAR complications in the MAUDE database with a focus on rectal wall infiltration. Radiation therapy is often used as a primary form of therapy for localized prostate cancer, with approximately 30-40% of men with prostate cancer undergoing radiation therapy. In 2015, SpaceOAR (developed by Boston Scientific), a polyethylene glycol-based gel, was granted FDA approval to be used to help reduce toxicity from radiation therapy in the treatment of prostate cancer. SpaceOAR works by creating a buffer between the target prostate tissue and the adjacent rectal wall. However, since its development, reporting of adverse events has been limited. At the 2024 AUA annual meeting, Dr. Shpeen and colleagues characterized how often rectal wall infiltration occurs and what the subsequent management was after injection.
The MAUDE Database was queried from 2015 to 2021 looking for adverse events, specifically rectal wall infiltration, associated with SpaceOAR and SpaceOAR Vue. The MAUDE database is a public database housing both mandatory and voluntary reports, allowing post-market surveillance for adverse events related to administration or effect of medical devices. Clavien-Dindo complication grade was assigned to each adverse event. Additional data was collected regarding a patient’s ability to continue radiation therapy despite rectal wall infiltration. Fisher’s exact test was used to compare Clavien-Dindo classification and whether the patient had any change or delay in their treatment.
Overall, there were 193 unique adverse events related to rectal wall infiltration that were recorded from 2019 to 2021. Prior to 2019 (2015-2018), reporting of adverse events was negligible. Of the 193 reported events, 170 (88%) were classified as Clavien-Dindo grade I complications. There were 11 (5.6%) grade 2, 11 (5.6%) grade 3, and 1 (0.5%) grade 4 complication:
Of the grade 3 complications, 9 of 11 were classified as grade 3b as they required flexible sigmoidoscopy and/or colonoscopy under general anesthesia. There were three patients went on to require diverting colostomy or ileostomy. Patient symptoms included severe rectal pain and hematochezia. Among the one grade 4 adverse event, the patient developed a recto-urethral fistula, along with osteomyelitis and soft tissue abscess, ultimately requiring an abdominoperineal resection and cystoprostatectomy with ileal conduit. When comparing complication grade and whether patients had their treatment course altered or delayed, there was no statistically significant difference (p = 0.43):
Dr. Shpeen noted several limitations of their study:
- There is underreporting, as this database requires appropriate reporting by device companies and health providers utilizing the device
- Lack of standardization in data reported for each event
- The study is a retrospective review
- Heterogeneity in radiation treatment planning
Dr. Shpeen concluded his presentation by discussing SpaceOAR complications in the MAUDE database with a focus on rectal wall infiltration with the following take-home messages:
- SpaceOAR, approved in 2015, has been previously shown to significantly reduce GI and GU toxicity related to radiation therapy
- However, side effects related to its placement, including rectal wall infiltration, have likely been underreported
- Rectal wall infiltration can pose a significant risk to the patient and may lead to significant morbidity
- While many patients can be treated conservatively with stool softeners and pain medication, there are reports of patients requiring more invasive surgeries
- Early recognition of severe complications is imperative to provide expeditious care and prevent additional procedures and/or surgery
Presented by: Benjamin Shpeen, MD, Maimonides Medical Center, Brooklyn, NY
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the 2024 American Urological Association (AUA) Annual Meeting, San Antonio, TX, Fri, May 3 – Mon, May 6, 2024.