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Anatomic considerations during SpaceOAR procedure, indicating the proximity of the bladder to the rectum. Reprinted from Urology 115, Karsh LI, Gross ET, Pieczonka CM et al. Absorbable Hydrogel Spacer Use in Prostate Radiotherapy, 39-44, 2018, with permission from Elsevier under the Creative Commons CC-BY-NC-ND license.
Source publication
After undergoing a SpaceOAR® gel placement prior to planned radiotherapy for Gleason 4 + 4 prostate cancer, a 70-year-old male experienced severe right buttock pain and urine passing from his rectum. A colonoscopy and follow-up pelvic MRI demonstrated a large rectourethral fistula. The fistula was treated surgically with a robot-assisted radical pr...
Context in source publication
Context 1
... treatment options, the patient chose androgen deprivation therapy with external beam radiation therapy. The patient received a 6-month Lupron injection, and five weeks later underwent T9-T11 and L2-S1 laminectomies without complication. Two months later, the patient underwent a transrectal ultrasound-guided placement of SpaceOAR® hydrogel (Fig. 2). The patient tolerated the procedure well initially but began to experience pain by the time he reached his car. That afternoon, he presented to the emergency department for constant right-sided buttock pain that radiated down his thigh. A CT pelvis showed no acute findings. Three weeks later, the patient began experiencing urine ...
Citations
... Three weeks later, he was diagnosed with rectourethral fistula. As he was no longer a candidate for radiation, he underwent a robotic prostatectomy and repair of the rectal defect with diverting loop ileostomy [11]. ...
A 60-year-old male presented with an elevated prostate-specific antigen (PSA) of 10 ng/ml. A transrectal ultrasound-guided prostate biopsy showed prostate adenocarcinoma GS 4+3 (grade 3) with 5 out of 12 cores positive for malignancy. He initially planned to have prostate stereotactic body radiation therapy (SBRT) with SpaceOAR gel insertion in his rectoprostatic space to reduce radiation to the rectum. Magnetic resonance imaging (MRI) two months after SpaceOAR insertion showed evidence of infiltration of the SpaceOAR within the anterior rectal wall. This delayed his treatment and he was started on a short course of androgen deprivation therapy with Leuprolide while waiting for absorption of the gel. After completion of androgen deprivation therapy, the patient was treated with external beam radiation therapy (EBRT) to the prostate, seminal vesicles, and pelvis to a total dose of 6000 centigray (cGy) in 20 fractions at a dose per fraction of 300 cGy. He did well after treatment with minimal side effects.
... Одно из самых грозных осложнений -септическое состояние -описано в 1 наблюдении. Фактически наиболее значимым (требующим хирургической коррекции) и при этом достаточно редким местным осложнением является формирование язвы или свища прямой кишки вследствие непосредственного ее повреждения при процедуре имплантации БДС или как исход развития инфекционных осложнений [56][57][58]. ...
The basic principles of the treatment of prostate cancer patients have underwent significant revisions in recent years. Modern radiotherapy techniques, which have demonstrated high efficacy and safety in long-term randomized trials, are beginning to take a leading position in the treatment of prostate cancer in an overwhelming number of clinical scenarios (National Comprehensive Cancer Network, 2021). Despite the obvious successes of radiation oncology, a number of important problems remain unresolved, first of all - the need to reduce the rates of radiation complications. The topographical anatomy of the prostate gland determines the main profiles of post-radiation damage: rectal and genitourinary radiation toxicity. The previous five years have been marked by a significant intensification of research work abroad aimed at clinical testing of a number of biopolymer compositions and products for use as spacers between irradiated structures and normal tissues. The experience has made it possible for the first time to consider the possibility of using spacers in radiotherapy treatment of prostate cancer in the modern recommendations of the European Association of Urology (2021). The analysis of the national literature shows a complete lack of publications on the possibilities of optimizing the radiation treatment of prostate cancer through the use of specers. The purpose of this work was the need to highlight this important and perspective clinical problem.
Despite the widespread use of perirectal spacers to reduce radiation-induced rectal toxicity during prostate cancer treatment, postmarketing data reveal rare but significant complications. This case report details a severe complication of rectourethral fistula necessitating robotic pelvic exenteration with urinary and faecal diversion following perirectal spacer placement. Although SpaceOAR has been shown to reduce rectal radiation dose, the ensuing clinical benefit remains inconclusive in real-world data. Our findings underscore the need for thorough patient counselling regarding the risks and benefits of spacer use, particularly given the lack of evidence for improved cancer control or gastrointestinal toxicity. We further review the literature to highlight the importance of physician technique during placement and the potential avenues for early identification and management of complications. Future research must aim to better characterise real-world risks and develop strategies for mitigating severe outcomes.
External beam radiation therapy is commonly used to treat prostate cancer, and gel spacers such as SpaceOAR Hydrogel (Boston Scientific, Marlborough, MA) are approved to limit local rectal radiation toxicity. SpaceOAR is usually reabsorbed in 12 to 24 weeks and excreted renally. It has a known low rate of rectourethral fistula that is usually associated with ectopic placement into the rectal wall. We present a case of a SpaceOAR Hydrogel insert persisting in a patient with chronic kidney disease on serial MRI scans for 59 weeks after placement with colovesical fistula development 81 weeks after placement of unclear association.
Objective
We retrospectively evaluated the efficacy of combining the SpaceOAR (SOAR) hydrogel with prostate brachytherapy, using colonoscopy findings to assess for radiation proctitis.
Methods
Among 731 patients undergoing iodine‐125 low‐dose‐rate prostate brachytherapy (LDR‐BT), SOAR was utilized in 394 patients (53.9%). Colonoscopy was performed for 97 patients (13.3%) to assess the presence, location, condition, and treatment of radiation proctitis. We also investigated treatment factors associated with the occurrence of radiation proctitis.
Results
Radiation proctitis was observed in 57 patients (7.8%) and 17 (2.3%) were treated with argon plasma coagulation (APC). The incidence of radiation proctitis was 12.2% in the non‐SOAR and 4.1% in the SOAR group ( p < 0.001). In the non‐SOAR group, the incidence of radiation proctitis was 6.6% for LDR‐BT monotherapy and increased to 22.0% when combined with external beam radiation therapy (EBRT) ( p = 0.001). However, in the SOAR group, these rates significantly decreased to 3.3% and 5.7% for monotherapy and combination therapy, respectively ( p = 0.035, p < 0.001). With SOAR, inflammation was observed directly above the DL in most patients (87.5%), and only one patient (6.3%) required APC. The absence of SOAR ( p < 0.001, HR = 0.29) and the concurrent use of EBRT ( p = 0.018, HR = 2.87) were identified as significant risk factors for the occurrence of radiation proctitis.
Conclusion
The use of SOAR significantly reduced the incidence of radiation proctitis in patients undergoing LDR‐BT monotherapy and combined EBRT. Inflammation primarily occurred directly above the DL; further examination is necessary to clarify its cause.
SpaceOAR hydrogel, a novel biodegradable spacer, is increasingly used in managing prostate cancer patients undergoing radiation therapy to minimize rectal radiation dose and associated complications. However, its use has raised new concerns regarding its potential complications and impact on subsequent imaging interpretation. This article provides a pictorial review of the imaging complications of using SpaceOAR hydrogel in prostate cancer patients. We present multiple examples demonstrating the types of complications that can occur, potential underlying mechanisms, and their impact on patient outcomes and imaging interpretation. This review aims to provide radiologists and oncologists with an updated understanding of these complications, guiding better patient management and interpretation of imaging studies.
Rectal spacers are commonly used in the radiotherapy for prostate cancers, serving as a means to protect the rectum and surrounding structures from radiation toxicity. Polyethylene Glycol-Based Gels (SpaceOAR ™ and Space-OAR Vue™, Boston Scientific) are the most commonly used rectal spacers. Given their increasingly widespread use and the relative paucity of radiology literature on this topic, it is imperative for the radiologist to recognize both the normal and abnormal placement of these polyethylene glycol-based rectal spacers, particularly as the latter may be associated with suboptimal therapy and/or complications.
Graphical abstract
Background
A major source of complications in vaginoplasty results from injury to the rectum during dissection of the neovaginal cavity. The SpaceOAR™ System is a rectal hydrogel spacer mostly used as a safety technique during prostate cancer treatment.
Objective
This was a feasibility study performed in a single cadaveric perineum.Methods: Prior to standard cavity dissection, SpaceOAR was injected transperineally into the Denonvilliers’ fascia under guidance of transrectal ultrasound. Dissection of the neovaginal cavity with spacer gel was qualitatively assessed to be significantly easier, allowing for a blunt and quick approach.
Results
A satisfactory vaginal length was achieved rapidly and safely.
Conclusions
We show that transgender vaginoplasty using this adaptation of SpaceOAR is technically feasible in the cadaveric model and may reduce the incidence of rectal injury or rectovaginal fistula during neovaginal cavity creation. Future experimental endeavours should focus on the reproducibility of this approach and characterise the degree of rectal protection provided.
Level of evidence
Not applicable
