Rectal Wall Research Articles

Long-term findings of rectal endoscopy and rectal bleeding after moderately hypofractionated, intensity-modulated radiotherapy for prostate cancer

To present rectal endoscopic findings and toxicity after definitive moderately hypofractionated, intensity-modulated radiotherapy (IMRT) for prostate cancer. We retrospectively reviewed patients who underwent IMRT for prostate cancer and underwent post-radiotherapy endoscopies between 2008 and 2018. Endoscopic findings were reviewed and graded using Vienna Rectoscopy Score (VRS). We have analyzed the association between endoscopic findings and rectal bleeding, and investigated risk factors for rectal bleeding. Total 162 patients met the inclusion criteria of this study. There was a trend of VRS worsening during the initial 3 years after radiotherapy followed by recovery. Rectal bleeding was highest at 1 year after radiotherapy and improved thereafter. The 5-year cumulative incidence of grade ≥ 2 rectal bleeding was 14.8%. In the multivariable Cox regression analysis, cardiovascular disease (hazard ratio [HR] 2.732, P = 0.037), rectal wall V65 (HR 1.158, P = 0.027), and VRS ≥ 3 in first post-radiotherapy endoscopy (HR 2.573, P = 0.031) were significant risk factors for rectal bleeding. After IMRT for prostate cancer, VRS and rectal bleeding worsened over 1–3 years after radiotherapy and recovered. Cardiovascular disease, rectal wall V65, and VRS ≥ 3 in first post-radiotherapy endoscopy were significant risk factors for rectal bleeding.

An acquired recto-perineal fistula as the outcome of sacrococcygeal teratoma treatment

Introduction. An acquired recto-perineal fistula in childhood is a quite rare pathology. One of its main causes is trauma of the perineal part of the rectum and anal canal. That is why, acquired rectoperineal fistulas most often develop after the correction of Hirschsprung’s disease and anorectal malformations.
 Material and methods. The publication presents a rare case of a newborn child with recurrent course of an acquired rectoperineal fistula which developed after sacrococcygeal teratoma treatment. The teratoma was removed when the child was 3 days old. The surgery was complicated with suture dehiscence in the rectal wall defect. After suturing, a separate sigmostoma was placed. At the age of 6 months, the sigmostoma was closed, but after a few days, fistulas were found in the area of drainage and postoperative scar, which required sigmostoma restoration. After the prescribed therapy, the fistulas were obliterated; the stoma was closed again. In 2 weeks, child’s general condition deteriorated, and newly appeared fistulas were noted. It was decided to perform demucosation of the disconnected rectum above the level of anal sphincter and to make fistula through drainage via the rectum lumen.
 Conclusion. Acquired recto-perineal fistulas in childhood is a rare recurrent disease. Though postoperative complications were detected in time, authors could not get independent closure of the fistula, despite numerous interventions. In fact, only the rectum extirpation allowed to separate the fistulous tract from the intestinal lumen. This type of intervention is considered a quite rare one; usually, such complication can be eliminated in a less radical way.

Dosimetric predictors for genitourinary toxicity in MR-guided stereotactic body radiation therapy (SBRT): Substructure with fraction-wise analysis.

MR-guided radiation therapy (MRgRT) systems provide superior soft tissue contrast than x-ray based systems and can acquire real-time cine for treatment gating. These features allow treatment planning margins to be reduced, allowing for improved critical structure sparing and reduced treatment toxicity. Despite this improvement, genitourinary (GU) toxicity continues to affect many patients. (1) To identify dosimetric predictors, potentially in combination with clinical parameters, of GU toxicity following SBRT by leveraging MRgRT to accurately monitor daily dose, beyond predicted dose calculated during planning. (2) Improve awareness of toxicity-sensitive bladder substructures, specifically the trigone and urethra. Sixty-nine prostate cancer patients (NCT04384770 clinical trial) were treated on a ViewRay MRIdian MRgRT system, with 40Gy prescribed to 95% of the PTV in over five fractions. Overall, 17 (24.6%) prostate patients reported acute grade 2 GU toxicity. The CTV, PTV, bladder, bladder wall, trigone, urethra, rectum, and rectal wall were contoured on the planning and daily treatment MRIs. Planning and daily treatment DVHs (0.1Gy increments), organ doses (min, max, mean), and organ volumes were recorded. Daily dose was estimated by transferring the planning dose distributions to the daily MRI based on the daily setup alignment. Patients were partitioned into a training (55) and testing set (14). Dose features were pre-filtered using a t-test followed by maximum relevance minimum redundancy (MRMR) algorithm. Logistic regression was investigated with regularization to select dosimetric predictors. Specifically, two approaches: time-group least absolute shrinkage and selection (LASSO), and interactive grouped greedy algorithm (IGA) were investigated. Shared features across the planning and five treatment fractions were grouped to encourage consistency and stability. The conventional flat non-temporally grouped LASSO was also evaluated to provide a solid benchmark. After feature selection, a final logistic regression model was trained. Dosimetric regression models were compared to a clinical regression model with only clinical parameters (age, baseline IPSS, prostate gland size, ADT usage, etc.) and a hybrid model, combining the best performing dosimetric features with the clinical parameters, was evaluated. Final model performance was evaluated on the testing set using accuracy, sensitivity, and specificity determined by the optimal threshold of the training set. IGA had the best testing performance with an accuracy/sensitivity/specificity of 0.79/0.67/0.82, selecting 12 groups covering the bladder (V19.8Gy, V20.5Gy), bladder wall (19.7Gy), trigone (15.9, 18.2, 43.3Gy), urethra (V41.4Gy, V41.7Gy), CTV (V41.9Gy), rectum (V8.5Gy), and rectal wall (1.2, 44.1Gy) dose features. Absolute bladder V19.8Gy and V20.5Gy were the most important features, followed by relative trigone 15.9 and 18.2Gy. Inclusion of clinical parameters in the hybrid model with IGA did not significantly change regression performance. Overall, IGA feature selection resulted in the best GU toxicity prediction performance. This exploratory study demonstrated the feasibility of identification and analysis of dosimetric toxicity predictors with awareness to sensitive substructures and daily dose to potentially provide consistent and stable dosimetric metrics to guide treatment planning. Further patient accruement is warranted to further assess dosimetric predictor and perform validation.

ПРИМЕНЕНИЕ АУТОЛОГИЧНОЙ МИКРОФРАГМЕНТИРОВАННОЙ АДИПОЗНОЙ ТКАНИ В ЛЕЧЕНИИ ПОСТЛУЧЕВОГО ЯЗВЕННОГО ПРОКТИТА

Abstract. Introduction. Radiation-induced ulcerative proctitis is a serious complication of cancer radiotherapy for prostate, cervix, uterine body, anal canal, and other pelvic tumors. Given the development pattern, there are currently no pathogenetic methods for the treatment of radiation-induced ulcerative proctitis. Aim: To develop a technique for and evaluate its effectiveness in the treatment of patients with radiation-induced rectal ulcers using autologous microfragmented adipose tissue. Materials and Methods. The study included 30 patients, of which 24 (80.0%) were women and 6 (20.0%) were men. Manual lipoaspiration was used to obtain autologous adipose tissue. Then we performed its microfragmentation via transfers. Concentrated autologous adipose tissue was introduced into the edges of the radiation-induced ulcerative defect on the rectal wall under endoscopic control. При контрольной ректоскопии через 6 месяцев у 28 (93,3 %) пациентов была отмечена полная эпителизация постлучевых язвенных дефек- тов прямой кишки. Results and Discussion. The manipulation, from sampling the adipose tissue through the end of injection lasted a little more than an hour (Me = 75.0 min). No intraoperative complications were detected. In one female patient (3.3%), a local recurrence of cervical cancer was found, and therefore that patient was excluded from the study. Control rectoscopy showed the complete epithelialization of post-radiation ulcerative rectal defects in 28 (93.3%) patients after 6 months. Conclusions. The technique proposed to use autologous microfragmented adipose tissue is affordable and effective in the treatment of patients with radiation-induced ulcerative proctitis.

Rectum and Bladder Toxicity in Postoperative Prostate Bed Irradiation: Dose-Volume Parameters Analysis.

Although prostate cancer treatment is increasingly effective, its toxicities pose a major concern. The aim of our study was to assess the rate of adverse events (AEs) and the prognostic value of dose-volume histogram (DVH) parameters for the occurrence of treatment toxicity in patients treated with post-prostatectomy prostate bed radiotherapy (RT). The AEs were scored according to the CTCAE v.5.0. The rectum and bladder were contoured according to the RTOG Guidelines. The DVH parameters were assessed using data exported from the ECLIPSE treatment-planning system. Genitourinary (GU) and gastrointestinal (GI) toxicity were analysed using consecutive dose thresholds for the percentage of an organ at risk (OAR) receiving a given dose and the QUANTEC dose constraints. A total of 213 patients were included in the final analysis. Acute grade 2 or higher (≥G2) GU AEs occurred in 18.7% and late in 21.3% of patients. Acute ≥G2 GI toxicity occurred in 11.7% and late ≥G2 in 11.2% of the patients. Five patients experienced grade 4 AEs. The most common adverse effects were diarrhoea, proctitis, cystitis, and dysuria. The most significant predictors of acute ≥G2 GI toxicity were rectum V47 and V46 (p < 0.001 and p < 0.001) and rectum wall V46 (p = 0.001), whereas the most significant predictors of late ≥G2 GI AEs were rectum wall V47 and V48 (p = 0.019 and p = 0.021). None of the bladder or bladder wall parameters was significantly associated with the risk of acute toxicity. The minimum doses to bladder wall (p = 0.004) and bladder (p = 0.005) were the most significant predictors of late ≥G2 GU toxicity. Postoperative radiotherapy is associated with a clinically relevant risk of AEs, which is associated with DVH parameters, and remains even in patients who fulfil commonly accepted dose constraints. Considering the lack of survival benefit of postoperative adjuvant RT, our results support delaying treatment through an early salvage approach to avoid or defer toxicity.

Treatment of pediatric H-type rectovestibular fistula with tension-free repair of rectal seromuscular layer

ObjectiveThis study aimed to assess the outcomes of a 7-year experience with tension-free repair of the rectal seromuscular layer for H-type rectovestibular fistula in female children with a normal anus. MethodsBetween May 2016 and January 2023, 86 patients with H-type rectovestibular fistula underwent a standardized surgical procedure conducted by the same surgical team. The procedure involved: (1) Identifying and locating the vestibular orifice. (2) Dissecting the fistula. (3) Dissecting the anterior rectal wall. (4) Repairing the fistula. (5) Closing the internal opening of the fistula. During the dissection of the rectovaginal septum, care was taken to avoid any harm to the posterior wall of the vagina while exposing the anterior rectal wall by 10–25 mm. ResultsFollow-up, conducted via telephone or outpatient visits, ranged from 3 months to 6 years and 11 months (median, 3.5 years). In 82 cases (95.35% of 86), primary healing was achieved, resulting in satisfactory perineal appearance, smooth stool passage, and regular defecation. In 4 cases (4.65% of 86), fistula recurrence occurred within 5 to 10 days post-surgery. One case healed within 3 weeks with 3% boric acid sitz baths. The other 2 cases underwent debridement 7 days after the initial operation, leading to successful recovery. The final case experienced a recurrence 1 year after surgery following resection and repair of the perineal fistula, and no further surgical intervention was pursued. ConclusionTension-free repair of the rectal seromuscular layer represents a straightforward, safe, and effective surgical approach for managing H-type rectovestibular fistula with a normal anus in female children.

Imaging diagnosis and evaluation of radiation-induced intestinal injury

Radiation-induced intestinal injury significantly impacts the quality of life and even prognosis of patients. Timely diagnosis and accurate assessment are crucial in clinical practice. Imaging examinations play a vital role in the diagnosis and evaluation of radiation-induced intestinal injury. CT offers fast scanning speed and wide coverage but has limited soft tissue resolution. On the other hand, MRI offers superior soft tissue resolution, along with the capability for multi-sequence and multi-parameter imaging, and the ability to assess the effect of tumor treatment. However, its scanning range is restricted. Endorectal ultrasound enables observation of rectal wall thickness, submucosal blood flow signals, and the development of micro-ulcers and fistulas. The key imaging features of radiation-induced intestinal injury include intestinal wall thickening, layered enhancement on contrast-enhanced scans, fistula formation, and abscess formation, and so on. Previous studies have established correlations between certain imaging features and the severity as well as prognosis of the disease. Nonetheless, these imaging features lack specificity, and require differentiation from tumors, ischemic changes, and other intestinal inflammatory lesions, considering the patient's radiotherapy history in conjunction with the imaging findings.

SpaceOAR hydrogel distribution and early complications in patients undergoing radiation therapy for prostate cancer.

Hydrogel spacers aim to separate the rectum from the prostate during radiation therapy for patients with prostate cancer to decrease the radiation dose and thus toxicity to the rectum. The aim of this study was to evaluate the distribution of the hydrogel spacer between the rectum and the prostate, to assess for hydrogel rectal wall infiltration and to assess for immediate complications. Retrospective study of 160 patients who had undergone hydrogel spacer placement. Distribution of the hydrogel was assessed on MRI. MRI images were reviewed for rectal wall injection or other malplacement of gel. Early post-procedure complications were recorded. 117 (73.1%) patients had a symmetrical distribution of the hydrogel spacer. The mean anteroposterior rectoprostatic separation was 10.2 ± 3.7 mm (range 0-27 mm). Seven (4.3%) patient had minimal rectal wall infiltration and one (0.6%) patient had moderate infiltration. One (0.6%) patient had an intraprostatic injection of hydrogel. Two (1.3%) patients required treatment in the emergency department: one for urinary retention and one for pain. Transperineal hydrogel placement separates the prostate from the rectum with a symmetrical distribution in the majority of cases prior to radiation therapy with a low rate of rectal wall injection and immediate complications. SpaceOAR hydrogel can be safely injected into radiation naive patients with low- or intermediate-risk organ-confined prostate cancer. The spacer separates the prostate from the rectum with a symmetrical distribution in the majority of cases prior to radiation therapy.

Proctoscopy following transrectal prostate biopsy can control rectal bleeding after prostate biopsy.

Rectal bleeding is a common complication of transrectal ultrasound-guided prostate biopsy (TRPB). Massive rectal bleeding after TRPB can be life threatening. We initiated proctoscopy after TRPB to clarify the incidence of rectal bleeding and evaluated the usefulness of proctoscopy for controlling bleeding after TRPB. Two hundred and fifty six patients who underwent TRPB were included in the study. TRPB was performed under local anesthesia. Post-biopsy, we performed a proctoscopy to evaluate the degree of rectal bleeding at four levels (G0, no bleeding; G1, traces; G2, venous bleeding requiring hemostasis; and G3, massive venous bleeding or arterial bleeding). Once the bleeding site on the rectal wall was identified, a gauze tampon was placed at the bleeding site and compressed for a few minutes. A second proctoscopy was performed to confirm complete hemostasis, after which the TRPB was terminated. Proctoscopy revealed that the degree of bleeding was G0 in 27 cases, G1 in 104 cases, G2 in 116 cases, and G3 in nine cases. Rectal bleeding that required hemostasis (G2 and G3) was observed in 125 of 256 cases (48.3%). Among the 125 cases, bleeding was stopped by compression in 121 cases; in the remaining four cases, bleeding continued despite compression and was stopped by suturing of the bleeding site. Suturing was performed by urologists, and none of the 256 patients had problematic posterior hemorrhage. Proctoscopy enables precise and effective pressure hemostasis. Moreover, suturing hemostasis under direct vision can be performed in cases in which pressure hemostasis is difficult. Continued proctoscopy allays urologists' fear of post-TRPB rectal bleeding.

Urethral Injury in Rectal Cancer Surgery: A Comprehensive Study Using Cadaveric Dissection, Imaging Analyses, and Clinical Series.

Male urethral injury during rectal cancer surgery is rare but significant. Scant information is available about the distances between the rectourethral space and neighboring structures. The aim of this study is to describe the anatomical relations of the male urethra. This three-pronged study included cadaveric dissection, retrospective MRI analysis, and clinical cases. Measurements included the R-Mu distance (shortest distance between the rectum and the membranous urethra), R-Am distance (distance from the anterior rectal wall to anal margin nearest to the membranous urethra), and the anal canal-rectum axis angle. The clinical study analyzed the incidence of urethral injury and associated factors among 244 consecutive men from January 2016 to January 2023. The overall incidence of urethral injury in our series was low (0.73%), but in men with tumors < 10 cm from the anal margin, it was 4% in abdominoperineal resection and 3.2% in TaTME. On preoperative MRI, the median R-Mu distance was 1 cm (IQR, range, 0.2-2.3), the median R-Am distance was 4.3 cm (range, 2-7.3), and the median anorectal angle was 128° (range, 87-160). In the cadaveric study (nine adult male pelvises), the mean R-Mu distance was 1.18 cm (range 0.8-2), and the mean R-Am distance was 2.64 cm (range 2.1-3). Avoiding urethral injury is crucial. The critical point for injury lies 2-7.3 cm from the anal margin, with a 0.2-2.3 cm distance between the rectum and the membranous urethra. Collaborating with anatomists and radiologists improves surgeons' anatomy knowledge.

Pattern of Residual Submucosal Involvement after Neoadjuvant Therapy for Rectal Cancer: A Rationale for the Utility of Endoscopic Submucosal Resection.

Background and Objectives: Full-thickness trans anal local excision for tumors with favorable response following neoadjuvant therapy for locally advanced rectal cancer (LARC) is a common strategy for organ preservation, but it could be associated with a high rate of postoperative complications. We describe the incidence and pattern of submucosal involvement in surgical specimens following neoadjuvant therapy for LARC and whether limiting local excision of the residual tumor bed to only mucosal/submucosal layers of the rectal wall is sufficient for accurately predicting the ypT status of residual cancer, providing a pathological rationale to replace full-thickness local excision by endoscopic submucosal resection. Materials and Methods: This was a single-institution retrospective study conducted at a teaching community hospital. We reviewed clinical and pathological findings with slides of 82 patients diagnosed with LARC treated at our center between 2006 and 2020. Eligibility criteria mirrored our current organ preservation trials. Results: No tumor was found in surgical specimens in 28 cases (34%). Additionally, 4, 22, 27, and 1 cases were staged as ypT1, ypT2, ypT3, and ypT4, respectively. Residual malignant cells were found in the submucosal layer in 98% of cases with ypT+ stage, with 'skip lesions' in only 2% of cases. Conclusions: A very high incidence of submucosal involvement is noticed in residual tumors after neoadjuvant therapy, providing pathological rationale to study the role of endoscopic submucosal resection as a restaging tool for tumors with favorable response after neoadjuvant therapy when organ preservation strategy is pursued. This study was limited by its retrospective design and relatively small number of patients.

Association Between Bowel Wall Thickening and Long-Term Outcomes in Decompensated Liver Cirrhosis.

Bowel wall thickening is commonly observed in liver cirrhosis, but few studies have explored its impact on the long-term outcomes of patients with cirrhosis. Overall, 118 patients with decompensated cirrhosis were retrospectively enrolled, in whom maximum wall thickness of small bowel, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum could be measured in computed tomography (CT) images. X-tile software was employed to determine the best cut-off values of each segment of bowel wall thickness for predicting the risk of further decompensation and death. Cumulative rates of further decompensation and death were calculated by Nelson-Aalen cumulative risk curve analyses. Predictors of further decompensation and death were evaluated by competing risk analyses. Sub-distribution hazard ratios (sHRs) were calculated. Cumulative rates of further decompensation were significantly higher in patients with wall thickness of ascending colon ≥ 11.7mm (P=0.014), transverse colon ≥ 3.2mm (P=0.043), descending colon≥9.8mm (P=0.035), and rectum ≥ 7.2mm (P=0.045), but not those with wall thickness of small bowel ≥ 8.5mm (P=0.312) or sigmoid colon≥7.1mm (P=0.237). Wall thickness of ascending colon≥11.7mm (sHR=1.70, P=0.030), transverse colon ≥ 3.2mm (sHR=2.15, P=0.038), and rectum≥7.2mm (sHR=2.38, P=0.045) were independent predictors of further decompensation, but not wall thickness of small bowel≥8.5mm (sHR=1.19, P=0.490), descending colon ≥ 9.8mm (sHR=1.53, P=0.093) or sigmoid colon≥7.1mm (sHR=0.63, P=0.076). Small bowel, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum wall thickness were not significantly associated with death. Colorectal wall thickening, but not small bowel wall, may be considered for the prediction of further decompensation in cirrhosis.

Effect of Transperineal Versus Transrectal Prostate Biopsy on the Quality of Hydrogel Spacer Placement in Men Prior to Radiation Therapy for Prostate Cancer

To determine whether prostate biopsy type affects spacer placement quality using a large sample of patients treated in the ambulatory setting. A retrospective cohort study was conducted on patients diagnosed with prostate cancer who underwent hydrogel spacer placement before primary radiation treatment between 2018 and 2023 after transperineal (TP) or transrectal (TR) prostate biopsy. Study outcomes were Spacer Quality Score (SQS) (0-2, with greater values indicating better placement), Rectal Wall Infiltration (RWI) (0-3, with lower values indicating lack of RWI), and the occurrence of other hydrogel complications. A total of 395 patients were included. A pre-hydrogel TR biopsy was performed in 273 patients (69.1%), while TP biopsy was performed in 122 (30.9%). A SQS ≥1 occurred in 308 (77.9%) patients. A greater proportion of TP patients had a favorable SQS (≥1) compared to those who underwent TR (87.7 vs 73.5%, P<.002). An RWI score ≥2 was found in 180 (45.6%) patients. The proportion of patients with an unfavorable RWI score (≥2) did not differ significantly by type of biopsy performed. Patients who had an interval of >70days between biopsy and hydrogel placement had significantly decreased odds of an RWI score ≥2 (odds ratio=0.42, 95% confidence interval: 0.21-0.83). Only one infection was found after hydrogel placement. The quality of hydrogel placement was significantly better in men who had undergone TP biopsy. Rectal wall infiltration was more common than previously reported but did not differ between TP and TR biopsies.

Application of a Radiopaque Viscous Hydrogel Spacer for Prostate Cancer Radiation Therapy: A Prospective Phase 2 Study

The aim of this study was to evaluate the application of a radiopaque viscous spacer (RVS) for prostate cancer radiation therapy (RT), including injection procedure, toxicity, treatment planning, image guidance, and imaging results up to 12 months after RT. RVS (median, 10 mL) was injected between prostate and rectal wall in 30 patients. Cone beam computed tomography (CT) was performed during the course of RT, a magnetic resonance imaging 3 and 12 months after RT. Injection and treatment tolerability were analyzed. The resulting distribution was compared with a control group of 30 patients with an initially fluid spacer. Procedure- or device-related adverse events were not observed. Signs of hydrogel migration were not found in any case. The volume decreased by 25% at 3 months after RT, and small residues were detected at 12 months after RT in 3 cases (10%). The median rectal volume percentage within the 90% isodose was 3.0% (interquartile range, 1.5%-4.5%). Acute and late gastrointestinal toxicities were found in 17% and 3%, respectively (all grade 1). The median distance between prostate and rectum at the base/midplane/apex was greater for RVS in comparison to initially fluid spacer (14/12/11 mm vs 12/10/10 mm, respectively), the gel symmetry (right vs left from midline) was comparable. The application was assessed to be easier to control by the users, and visibility in cone beam CT as good. The injection of a radiopaque viscous hydrogel spacer resulted in a prostate-rectum distance of >10 mm in most cases. The resulting rectum volume within the high-dose region and RT toxicity were very low. Advantages in comparison to the conventional hydrogel spacer are predominantly an improved placement control during the injection process and good visibility on CT.

S3155 A Case of Rectal Bleeding From Ulcer Secondary to Erosion of SpaceOAR Gel Into the Rectal Wall

S3155 A Case of Rectal Bleeding From Ulcer Secondary to Erosion of SpaceOAR Gel Into the Rectal Wall

Colonoscopy-assisted percutaneous sigmoidopexy (CAPS) for complete rectal prolapse treatment: Case series.

Background and study aims We have previously reported on the effectiveness of colonoscopy-assisted percutaneous sigmoidopexy (CAPS) for sigmoid volvulus treatment. This study describes the CAPS application to treat complete rectal prolapse by straightening and fixing the rectum. Complete rectal prolapse is common in older women. Due to their comorbidities, management must comprise a simple, safe, and reliable surgical method not involving general anesthesia or colon resection. Patients and methods We enrolled 13 patients in our outpatient department diagnosed with complete rectal prolapse between June 2016 and 2021. The endoscope was advanced into the anterior proximal rectal wall, straightening the intussuscepted sigmoid colon and rectum to approximate the puncture site. The fixation sites were anesthetized with 1% xylocaine, and a 2-mm skin incision was made using a scalpel. A two-shot anchor was used to fix the sigmoid colon to the abdominal wall (Olympus, Tokyo, Japan). Results The median patient age was 88 years (range: 50-94). The median CAPS procedure time was 30 minutes (range: 20-60). In one patient, the transverse colon was accidentally punctured and interposed between the abdominal wall and sigmoid colon, requiring a laparotomy to remove the causative fixation thread and provide re-fixation. Fecal incontinence was resolved in 10 of 13 cases. Conclusions CAPS is a quick and simple procedure. In addition, it is a treatment option for complete rectal prolapse that can be performed under local anesthesia.

Application of a Radiopaque Viscous Hydrogel Spacer for Prostate Cancer Radiotherapy - A Prospective Multi-Institutional Phase II Study.

Rectal dose can be significantly decreased after spacer application. An initially fluid spacer (FS) spreads in a predetermined space, whereas the positioning of a viscous spacer is determined by needle guidance. The aim of this study was to evaluate the application a radiopaque viscous spacer (RVS) for prostate cancer radiotherapy (RT). In 30 patients including three centers, 10ml (median) of a RVS was injected between the prostate and anterior rectal wall. The resulting distance and distribution were determined in different planes and compared with a control group of 30 patients with a FS. A cone beam computed tomography (CBCT) was performed at least at the end of RT, a magnetic resonance imaging (MRI) 3 months and 12 months after RT. Injection and treatment tolerability were analyzed. With a median prostate volume of 40cm3, no overlap was found between planning target volume and rectal volume in most cases (median = 0cm3, interquartile range, IQR 0-0.6cm3). The median contoured RVS before, at the end and 3 months after RT was 8.5cm3, 8.7cm3 und 6.4cm3. Signs of hydrogel migration were not found in any case. Hydrogel visibility in CBCT was rated with "4" on a scale between 1 (poor) and 5 (excellent). Small residues were detected in the MRI 12 months after RT in 3 cases (10%). The median distance between prostate and rectum at the base / midplane / apex was 14mm / 12mm / 11mm. The median rectal volume percentage within the 90% and 80% isodoses was 3.0% (IQR 1.5-4.5%) bzw. 5.9% (IQR 3.0-10.6%). On a scale between 1 (difficult) and 5 (very easy), ease of application was rated with "3-4". Procedure- or device related adverse events have not been observed in any case. Acute and late gastrointestinal toxicities were found in 17% and 3%, respectively (all grade 1). The control of gel distribution of RVS relative to FS was rated with "3-5" on a scale between 1 (much worse) and 5 (much better), the ease of application relative to FS with "2-3" on a scale between 1 (much harder) and 5 (much easier). With a median contoured FS volume of 9.9cm3, the prostate-rectum distance at the base / midplane / apex was 12mm / 10mm / 10mm (significantly smaller in comparison to RVS). However, the lateral gel extension of RVS was smaller in all planes, statistically significant for all comparisons (base: 28mm vs. 34mm, midplane: 28mm vs. 32mm, apex: 21mm vs. 26mm). The gel symmetry (right vs. left) was comparable. The application of a radiopaque viscous hydrogel spacer is harder in comparison to the initially fluid spacer. However, it can be better controlled and is achievable without any complications. Visibility in CBCT is good. The resulting prostate-rectum distance is >10mm in most cases and slightly larger at the base in comparison to FS. The resulting rectum volume within the high dose region and radiotherapy toxicity are very low.

CT vs. MRI: Which is More Accurate in Grading Rectal Wall Infiltration after Hydrogel Spacer Placement for Prostate Cancer Patients?

The purpose of this study was to evaluate the incidence and severity of rectal wall infiltration (RWI) in prostate cancer patients after rectal hydrogel spacer implantation, a commonly used procedure to minimize rectal radiation exposure during prostate radiotherapy. The study aimed to determine correlation of RWI using computed tomography (CT) scans and magnetic resonance imaging (MRI) scans in order to determine the optimal post-placement imaging modality. This retrospective study was conducted on 370 patients diagnosed with localized prostate cancer who underwent rectal hydrogel spacer placement from 2020 to 2022. CT scans were performed on all patients, with a smaller subset also undergoing MRI scans. The images were independently evaluated by three radiation oncologists to grade RWI levels using a standardized scoring system based on CT and MRI images after hydrogel placement. The levels were categorized as 0 (no RWI), 1 (focal RWI), 2 (moderate RWI), and 3 (significant RWI). Any grade of RWI was identified in 79.8% of men with the majority (41%) being RWI grade 1. The median time for CT scans was 9 days after hydrogel spacer placement and 14.5 days for MRI scans. For the subset of patients with both CT and MRI scans after spacer (mostly SpaceOAR Vue), RWI was detected in 58.33% of patients based on CT and 61.11% of patients based on MRI. Table 1 shows the mean percentage of patients with each score of RWI for each imaging modality. MRI was more likely to lead to a designation of RWI of any grade compared to CT and more often led to detection of RWI grades 2-3. Our findings demonstrate that the incidence and severity of RWI may be higher than previously reported in clinical trials and that MRI may be a more sensitive imaging modality. Caution is needed in the utilization of rectal spacer gels given the potential for complications with misplacement prior to radiation therapy. Further study is warranted to determine the potential impact of low-grade RWI on the safety of subsequent treatment.

Association of Apical Spacing with Bowel Quality-of-Life: A Secondary Analysis of the Hyaluronic Acid Randomized Trial.

Recently, a randomized trial (NCT04189913) reported that a hyaluronic acid (HA) rectal spacer reduced acute grade 2+ gastrointestinal (GI) toxicity for hypofractionated radiation therapy (RT). However, 26.5% of patients who received the spacer experienced a minimally clinically important difference (MCID; 5 points) in EPIC bowel quality-of-life (QOL). We evaluated whether characteristics of the spacer implant, particularly apical separation, were associated with change in bowel QOL at 3-months and acute grade 1+ GI toxicity. We conducted a secondary analysis of 136 patients randomized to receive the HA spacer. The post-spacer implant structure sets and treatment plans were analyzed. The mid-plane (MP) was defined as the prostate center-of-mass. Four horizontal planes were defined at the superior (MP +1 cm), mid-gland, inferior (MP - 1 cm), and apex of the prostate. Separations between the prostate and anterior rectal wall at midline were computed at each plane in a custom Python programming environment. Implant symmetry was computed based on a previously published method (Fischer-Valuck, PRO, 2017). The volume of rectum receiving > = 30 Gy (rV30) was extracted from DVHs; rV30 has been associated with bowel frequency, fecal incontinence, and rectal pain for hypofractionated RT (Wilkins, IJROBP, 2020). First, we evaluated whether any of the 4 separation or symmetry variables were associated with rV30. Then, we evaluated whether significant spacing variables, rV30, and baseline bowel QOL were predictive of the change in bowel QOL at 3-months using multivariate linear regression. Finally, we evaluated whether significant spacing variables and rV30 were predictive of acute grade 1+ GI toxicity (21 events) within 3-months, utilizing multivariate logistic regression. The mean (standard deviation) superior, mid-gland, inferior, and apex separations were 15.6 (SD 6.0), 12.7 (3.7), 11.2 (3.7), and 9.7 (4.0), respectively. 130 of 136 (95.6%) had a symmetry score of 1 (symmetric). Apical separation was the only variable significantly associated with rV30 (r = -0.32; p < 0.01). On multivariate analysis, apical separation (0.41/mm; p = 0.01) was significantly associated with the change in bowel QOL, after adjusting for baseline bowel score (p = 0.0002) and rectum V30 (p = 0.50). Mean (SD) changes in bowel QOL were 0.01 (5.9) and -3.7 (8.1) for apical separations > = 10 vs <10 mm, respectively. Respective percentages of patients with a bowel MCID were 14.8% and 36.6% (p = 0.006). However, apical separation was not associated with increased odds of experiencing grade 1+ GI toxicity (p = 0.98), when adjusted for rectum V30 (odds ratio 1.04; p = 0.04). Increased apical separation may be associated with improved EPIC bowel QOL at 3-months for patients who received a HA rectal spacer prior to hypofractionated RT. This finding is clinically important, because HA can be deliberately injected into the perirectal space at the level of the prostate apex.

Location of Local Recurrences Post-Prostatectomy Detected by 18F-DCPFyL and Implications for Salvage Radiotherapy Target Volumes.

The use of prostate-specific membrane antigen (PSMA) PET scans have improved detection of recurrent prostate cancer for biochemical failure post-prostatectomy. The primary aim of this study is to assess the location of local recurrences for PSMA PET positive disease post-prostatectomy relative to anatomical landmarks and to inform salvage radiotherapy contouring guidelines. This is a retrospective study of patients who underwent a staging PSMA PET-CT scan with 18F-DCFPyL tracer. Eligible patients included men with biochemical recurrence (PSA >0.2ng/mL) post-prostatectomy for prostate adenocarcinoma. PSMA positive local disease (GTV) was marked on the CT scan of the PSMA PET/CT, using the PSMA PET scan fused as the secondary dataset. Reference structures were contoured to compare the positional relationship to the GTV local recurrence. Centroids of each GTV position were measured to the closest border of the reference structures and distance measured. Forty-five patients had a local recurrence on PSMA PET, 28/45 with prostate bed recurrence and 17/45 with seminal vesicle bed recurrence. The median age was 72.7 years, median pre-treatment PSA 0.515 ng/ml (0.2-11.1), pT2 in 37.8% and pT3 in 62.2, ISUP G2-3 was 66.7%, ISUP 4-5 29.6%, 67% ECE, 15.4% SV involvement and 40% positive margin. For prostate bed recurrences, 93.6% of GTVs were within 15mm from the inferior border of pubic symphysis (median 3.3mm [-9.8-15.4]), 83.9% within 10mm from the VUA (median 3.3mm [-17.4-15.9]), and 80.6% were greater than 10mm from the most superior slice of the penile bulb (median 16.4mm [1-29.5]). Laterally, 83.9% of recurrences were within 10mm of midline and 41.9% within 5mm (median 3.3mm [-13.56-11.59]) and all were contained within levator, 35.5% within 5mm (median 7.7 [1-22.6]) of the medial muscle border. 29.0% were within 5mm from the anterior edge of the rectal wall (median -7mm [-32.3-0.5]). Seminal vesicle bed recurrences were within 17.5mm of upper border of pubic symphysis for 88.9% of patients (median -4.69mm[-30.8to18.2]), 100% were more than 7.5mm inferiorly from the vas deferens (median-22.1mm[-32.7to-7.7]). Laterally, 100% recurrences were more than 7.5mm medial from obturator internus (median 5.37mm [-23.1to37.8]), and 88.9% were more than 10mm from midline (median 23.1mm [2.0-36.6]). The 18F-DCFPyL PSMA PET local recurrences can provide detailed localization of prostate bed and seminal vesicle recurrences. Our data can inform contouring guidelines for salvage radiotherapy to the prostate bed, particularly when using anatomical landmarks to define cranio-caudal extent of target volumes. For target volume laterally, the medial wall of levator ani would encompass all prostate bed recurrences, and no seminal vesicles recurrences were seen at the medial border of the obturator internus muscle.