Low Anterior Resection Syndrome. Anatomical Changes after Anterior Rectal Resection.

In this editorial, the authors bring to the attention of surgeons a personal point of view with the intention of offering a series of anatomical arguments to explain the high rate of functional complications following ultralow rectal resections, resections dominated by faecal incontinence of various intensities. Having as a starting point the anatomy of the pelvic floor and the posterior perineum, the authors are concerned with the functional outcomes of the sphincter-saving anterior rectal resection, regarding the low and ultralow resection. Technically, a conservative surgery for low rectal cancer has been currently performed. If 25 years ago the abdominoperineal resection was the gold standard for rectal cancer located under 7cm from the anal verge, nowadays the preservation of the anal canal as a partner for colon anastomosis has been accomplished. Progressively, from a desire to preserve the normal passage of stool into the anal canal, as anatomically and physiologically as possible, the distal limit of resection was lowered to 2-4 cm from the anal verge and ultra-low anastomoses were created, within the anal sphincter complex. The stated goal: keep the oncological safety standard and, at the same time, avoid definitive colostomy. Starting from the normal anatomy of the pelvic floor and the anorectal segment, the authors take a look at the alterations of the visceral, muscular, and nerve structures as a consequence of the low anterior resection and, particularly, the ultralow anterior resection. A significant degree of functional outcomes regarding defecation, with the onset of marked disabilities of anal continence, the major consequence being anal incontinence (30-70%), have been noticed. The authors go under review for the main anatomical and physiological changes that accompany anterior rectal resection. Conclusions: Thus, the following questions arise: what is the lower limit of resection to avoid total fecal incontinence? Is total incontinence a greater handicap than colostomy or is it not? The answers cannot be supported by solid arguments at this time, but the need to initiate future studies dedicated to this problem emerges.

Duhamel and transanal endorectal pull-throughs for Hirschsprung disease: a Bayesian network meta-analysis.

BACKGROUND: To comprehensively compare the effects of open Duhamel (OD), laparoscopic-assisted Duhamel (LD), transanal endorectal pull-through (TEPT), and laparoscopic-assisted endorectal pull-through (LEPT) in Hirschsprung disease. METHODS: PubMed, Embase, Cochrane Library, Web of Science, CNKI, WanFang, and VIP were comprehensively searched up to August 4, 2022. The outcomes were operation-related indicators and complication-related indicators. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to evaluate the quality of evidence. Network plots, forest plots, league tables and rank probabilities were drawn for all outcomes. For measurement data, weighted mean differences (WMDs) and 95% credibility intervals (CrIs) were reported; for enumeration data, relative risks (RRs) and 95%CrIs were calculated. RESULTS: Sixty-two studies of 4781 patients were included, with 2039 TEPT patients, 1669 LEPT patients, 951 OD patients and 122 LD patients. Intraoperative blood loss in the OD group was more than that in the LEPT group (pooled WMD = 44.00, 95%CrI: 27.33, 60.94). Patients lost more blood during TEPT versus LEPT (pooled WMD = 13.08, 95%CrI: 1.80, 24.30). In terms of intraoperative blood loss, LEPT was most likely to be the optimal procedure (79.76%). Patients undergoing OD had significantly longer gastrointestinal function recovery time, as compared with those undergoing LEPT (pooled WMD = 30.39, 95%CrI: 16.08, 44.94). The TEPT group had significantly longer gastrointestinal function recovery time than the LEPT group (pooled WMD = 11.49, 95%CrI: 0.96, 22.05). LEPT was most likely to be the best operation regarding gastrointestinal function recovery time (98.28%). Longer hospital stay was observed in patients with OD versus LEPT (pooled WMD = 5.24, 95%CrI: 2.98, 7.47). Hospital stay in the TEPT group was significantly longer than that in the LEPT group (pooled WMD = 1.99, 95%CrI: 0.37, 3.58). LEPT had the highest possibility to be the most effective operation with respect to hospital stay. The significantly reduced incidence of complications was found in the LEPT group versus the LD group (pooled RR = 0.24, 95%CrI: 0.12, 0.48). Compared with LEPT, OD was associated with a significantly increased incidence of complications (pooled RR = 5.10, 95%CrI: 3.48, 7.45). Patients undergoing TEPT had a significantly greater incidence of complications than those undergoing LEPT (pooled RR = 1.98, 95%CrI: 1.63, 2.42). For complications, LEPT is most likely to have the best effect (99.99%). Compared with the LEPT group, the OD group had a significantly increased incidence of anastomotic leakage (pooled RR = 5.35, 95%CrI: 1.45, 27.68). LEPT had the highest likelihood to be the best operation regarding anastomotic leakage (63.57%). The incidence of infection in the OD group was significantly higher than that in the LEPT group (pooled RR = 4.52, 95%CrI: 2.45, 8.84). The TEPT group had a significantly increased incidence of infection than the LEPT group (pooled RR = 1.87, 95%CrI: 1.13, 3.18). LEPT is most likely to be the best operation concerning infection (66.32%). Compared with LEPT, OD was associated with a significantly higher incidence of soiling (pooled RR = 1.91, 95%CrI: 1.16, 3.17). Patients with LEPT had the greatest likelihood not to develop soiling (86.16%). In contrast to LD, LEPT was significantly more effective in reducing the incidence of constipation (pooled RR = 0.39, 95%CrI: 0.15, 0.97). LEPT was most likely not to result in constipation (97.81%). LEPT was associated with a significantly lower incidence of Hirschprung-associated enterocolitis (HAEC) than LD (pooled RR = 0.34, 95%CrI: 0.13, 0.85). The OD group had a significantly higher incidence of HAEC than the LEPT group (pooled RR = 2.29, 95%CrI: 1.31, 4.0). The incidence of HAEC was significantly greater in the TEPT group versus the LEPT group (pooled RR = 1.74, 95%CrI: 1.24, 2.45). LEPT was most likely to be the optimal operation in terms of HAEC (98.76%). CONCLUSION: LEPT may be a superior operation to OD, LD and TEPT in improving operation condition and complications, which might serve as a reference for Hirschsprung disease treatment.

Preoperative prediction of perineural invasion of rectal cancer based on a magnetic resonance imaging radiomics model: A dual-center study.

BACKGROUND: Perineural invasion (PNI) has been used as an important pathological indicator and independent prognostic factor for patients with rectal cancer (RC). Preoperative prediction of PNI status is helpful for individualized treatment of RC. Recently, several radiomics studies have been used to predict the PNI status in RC, demonstrating a good predictive effect, but the results lacked generalizability. The preoperative prediction of PNI status is still challenging and needs further study. AIM: To establish and validate an optimal radiomics model for predicting PNI status preoperatively in RC patients. METHODS: This retrospective study enrolled 244 postoperative patients with pathologically confirmed RC from two independent centers. The patients underwent pre-operative high-resolution magnetic resonance imaging (MRI) between May 2019 and August 2022. Quantitative radiomics features were extracted and selected from oblique axial T2-weighted imaging (T2WI) and contrast-enhanced T1WI (T1CE) sequences. The radiomics signatures were constructed using logistic regression analysis and the predictive potential of various sequences was compared (T2WI, T1CE and T2WI + T1CE fusion sequences). A clinical-radiomics (CR) model was established by combining the radiomics features and clinical risk factors. The internal and external validation groups were used to validate the proposed models. The area under the receiver operating characteristic curve (AUC), DeLong test, net reclassification improvement (NRI), integrated discrimination improvement (IDI), calibration curve, and decision curve analysis (DCA) were used to evaluate the model performance. RESULTS: Among the radiomics models, the T2WI + T1CE fusion sequences model showed the best predictive performance, in the training and internal validation groups, the AUCs of the fusion sequence model were 0.839 [95% confidence interval (CI): 0.757-0.921] and 0.787 (95%CI: 0.650-0.923), which were higher than those of the T2WI and T1CE sequence models. The CR model constructed by combining clinical risk factors had the best predictive performance. In the training and internal and external validation groups, the AUCs of the CR model were 0.889 (95%CI: 0.824-0.954), 0.889 (95%CI: 0.803-0.976) and 0.894 (95%CI: 0.814-0.974). Delong test, NRI, and IDI showed that the CR model had significant differences from other models (P < 0.05). Calibration curves demonstrated good agreement, and DCA revealed significant benefits of the CR model. CONCLUSION: The CR model based on preoperative MRI radiomics features and clinical risk factors can preoperatively predict the PNI status of RC noninvasively, which facilitates individualized treatment of RC patients.

Anorectal function and symptoms 6 months after robot-assisted laparoscopic radical prostatectomy: a single-center study.

INTRODUCTION: Robot-assisted laparoscopic radical prostatectomy (RALP) is a common procedure for the treatment of localised prostate cancer. Anorectal symptoms such as fecal incontinence (FI), rectal urgency or disturbed defecation have been reported after the operation. Anorectal function is dependent on the integrity of anal and pelvic nerves and muscles, rectal sensory function as well as rectal reservoir function. The aim of this study was to investigate the potential influence of RALP on anorectal physiological function and bowel symptoms. MATERIALS AND METHODS: In this pilot study, 29 patients with localised prostate cancer scheduled for RALP were included. Anorectal physiology was used to measure rectal sensitivity and reservoir function as well as anal sphincter pressures. Bowel symptoms were measured by a bowel function questionnaire and a 2-week bowel function diary. Measurements were done before the operation and repeated at 6 months after the operation. RESULTS: The study observed a significant postoperative increase in rectal sensory threshold for rectal balloon distention, from 20 to 40 mmHg, P < 0.001. This change is indicative of a decrease in rectal sensation after RALP. There were no other statistical significant differences in any of the physiological tests performed. Importantly, there was no change in any of the bowel symptoms after surgery. CONCLUSION: This study showed that RALP may lead to impaired rectal sensory function. This finding did not, however, seem to have any influence on the patients´ postoperative clinical bowel function.

A current view of mitochondria damage and the diversity of lipopigment inclusions in neuronal ceroid lipofuscinose type 2 from rectal biopsy.

Neuronal ceroid lipofuscinoses (NCLs) are a growing group of neurodegenerative storage diseases, in which specific features are sought to facilitate the creation of a universal diagnostic algorithm in the future. In our ultrastructural studies, the group of NCLs was represented by the CLN2 disease caused by a defect in the TPP1 gene encoding the enzyme tripeptidyl-peptidase 1. A 3.5-year-old girl was affected by this disease. Due to diagnostic difficulties, the spectrum of clinical, enzymatic, and genetic tests was extended to include analysis of the ultrastructure of cells from a rectal biopsy. The aim of our research was to search for pathognomonic features of CLN2 and to analyse the mitochondrial damage accompanying the disease. In the examined cells of the rectal mucosa, as expected, filamentous deposits of the curvilinear profile (CVP) type were found, which dominated quantitatively. Mixed deposits of the CVP/fingerprint profile (FPP) type were observed less frequently in the examined cells. A form of inclusions of unknown origin, not described so far in CLN2 disease, were wads of osmophilic material (WOMs). They occurred alone or co-formed mixed deposits. In addition, atypically damaged mitochondria were observed in muscularis mucosae. Their deformed cristae had contact with inclusions that looked like CVPs. Considering the confirmed role of the c subunit of the mitochondrial ATP synthase in the formation of filamentous lipopigment deposits in the group of NCLs, we suggest the possible significance of other mitochondrial proteins, such as mitochondrial contact site and cristae organizing system (MICOS), in the formation of these deposits. The presence of WOMs in the context of searching for ultrastructural pathognomonic features in CLN2 disease also requires further research.

Anorectal lymphogranuloma venereum among men who have sex with men: a 3-year nationwide survey, France, 2020 to 2022.

BackgroundIn France, lymphogranuloma venereum (LGV) testing switched from universal to selective testing in 2016.AimTo investigate changes in LGV-affected populations, we performed a nationwide survey based on temporarily reinstated universal LGV testing from 2020 to 2022.MethodsEach year, during three consecutive months, laboratories voluntarily sent anorectal Chlamydia trachomatis-positive samples from men and women to the National Reference Centre for bacterial sexually transmitted infections. We collected patients' demographic, clinical and biological data. Genovars L of C. trachomatis were detected using real-time PCR. In LGV-positive samples, the ompA gene was sequenced.ResultsIn 2020, LGV positivity was 12.7% (146/1,147), 15.2% (138/907) in 2021 and 13.3% (151/1,137) in 2022 (p > 0.05). It occurred predominantly in men who have sex with men (MSM), with rare cases among transgender women. The proportion of HIV-negative individuals was higher than that of those living with HIV. Asymptomatic rectal LGV increased from 36.1% (44/122) in 2020 to 52.4% (66/126) in 2022 (p = 0.03). Among users of pre-exposure prophylaxis (PrEP), LGV positivity was 13.8% (49/354) in 2020, 15.6% (38/244) in 2021 and 10.9% (36/331) in 2022, and up to 50% reported no anorectal symptoms. Diversity of the LGV ompA genotypes in the Paris region increased during the survey period. An unexpectedly high number of ompA genotype L1 variant was reported in 2022.ConclusionIn rectal samples from MSM in France, LGV positivity was stable, but the proportion of asymptomatic cases increased in 2022. This underscores the need of universal LGV testing and the importance of continuous surveillance.

Differential Colonization and Mucus Ultrastructure Visualization in Bovine Ileal and Rectal Organoid-Derived Monolayers Exposed to Enterohemorrhagic Escherichia coli.

Enterohemorrhagic Escherichia coli (EHEC) is a critical public health concern due to its role in severe gastrointestinal illnesses in humans, including hemorrhagic colitis and the life-threatening hemolytic uremic syndrome. While highly pathogenic to humans, cattle, the main reservoir for EHEC, often remain asymptomatic carriers, complicating efforts to control its spread. Our study introduces a novel method to investigate EHEC using organoid-derived monolayers from adult bovine ileum and rectum. These polarized epithelial monolayers were exposed to EHEC for four hours, allowing us to perform comparative analyses between the ileal and rectal tissues. Our findings mirrored in vivo observations, showing a higher colonization rate in the rectum compared with the ileum (44.0% vs. 16.5%, p < 0.05). Both tissues exhibited an inflammatory response with increased expression levels of TNF-a (p < 0.05) and a more pronounced increase of IL-8 in the rectum (p < 0.01). Additionally, the impact of EHEC on the mucus barrier varied across these gastrointestinal regions. Innovative visualization techniques helped us study the ultrastructure of mucus, revealing a net-like mucin glycoprotein organization. While further cellular differentiation could enhance model accuracy, our research significantly deepens understanding of EHEC pathogenesis in cattle and informs strategies for the preventative measures and therapeutic interventions.

Ammonia transport in the excretory system of mosquito larvae (Aedes aegypti): Rh protein expression and the transcriptome of the rectum.

The role of the mosquito excretory organs (Malpighian tubules, MT and hindgut, HG) in ammonia transport as well as expression and function of the Rhesus (Rh protein) ammonia transporters within these organs was examined in Aedes aegypti larvae and adult females. Immunohistological examination revealed that the Rh proteins are co-localized with V-type H+-ATPase (VA) to the apical membranes of MT and HG epithelia of both larvae and adult females. Of the two Rh transporter genes present in A. aegypti, AeRh50-1 and AeRh50-2, we show using quantitative real-time PCR (qPCR) and an RNA in-situ hybridization (ISH) assay that AeRh50-1 is the predominant Rh protein expressed in the excretory organs of larvae and adult females. Further assessment of AeRh50-1 function in larvae and adults using RNAi (i.e. dsRNA-mediated knockdown) revealed significantly decreased [NH4+] (mmol l-1) levels in the secreted fluid of larval MT which does not affect overall NH4+ transport rates, as well as significantly decreased NH4+ flux rates across the HG (haemolymph to lumen) of adult females. We also used RNA sequencing to identify the expression of ion transporters and enzymes within the rectum of larvae, of which limited information currently exists for this important osmoregulatory organ. Of the ammonia transporters in A. aegypti, AeRh50-1 transcript is most abundant in the rectum thus validating our immunohistochemical and RNA ISH findings. In addition to enriched VA transcript (subunits A and d1) in the rectum, we also identified high Na+-K+-ATPase transcript (α subunit) expression which becomes significantly elevated in response to HEA, and we also found enriched carbonic anhydrase 9, inwardly rectifying K+ channel Kir2a, and Na+-coupled cation-chloride (Cl-) co-transporter CCC2 transcripts. Finally, the modulation in excretory organ function and/or Rh protein expression was examined in relation to high ammonia challenge, specifically high environmental ammonia (HEA) rearing of larvae. NH4+ flux measurements using the scanning-ion selective electrode (SIET) technique revealed no significant differences in NH4+ transport across organs comprising the alimentary canal of larvae reared in HEA vs freshwater. Further, significantly increased VA activity, but not NKA, was observed in the MT of HEA-reared larvae. Relatively high Rh protein immunostaining persists within the hindgut epithelium, as well as the ovary, of females at 24-48 h post blood meal corresponding with previously demonstrated peak levels of ammonia formation. These data provide new insight into the role of the excretory organs in ammonia transport physiology and the contribution of Rh proteins in mediating ammonia movement across the epithelia of the MT and HG, and the first comprehensive examination of ion transporter and channel expression in the mosquito rectum.

Comparison of postoperative urinary complications in laparoscopic-assisted anorectoplasty versus posterior sagittal anorectoplasty for anorectal malformation with rectourethral fistula.

BACKGROUND: Long-term urinary outcomes after anorectal malformation (ARM) repair are affected by surgical approach and sacral anomalies. This study aimed to compare laparoscopic-assisted anorectoplasty (LAARP) and posterior sagittal anorectoplasty (PSARP) in terms of urinary complications. METHODS: Between 2001 and 2022, 45 patients were treated with LAARP or PSARP. The rectourethral fistula and inflow angle between the fistula and rectum was confirmed by preoperative colonography. The incidence of urinary complications and treatment were compared between the two groups. RESULTS: Four patients (14%) had remnant fistula and five patients (17%) had neurogenic bladder dysfunction in LAARP group, while three patients (18%) had urethral injury in PSARP group. All patients with remnant fistula were asymptomatic and followed without treatment. The incidence of remnant fistula improved between earlier decade and later decade. In all cases with urethral injury, suture repair was performed and no postoperative leakage was noted. All five patients with neurogenic bladder dysfunction had spine abnormalities that required clean intermittent catheterization (CIC) and two were free from CIC finally. CONCLUSIONS: It is important to check inflow angle preoperatively to prevent remnant fistula. For PSARP, meticulous dissection is required when separating fistula from urethra because they create common wall. The most contributing factor to neurogenic bladder is sacral anomalies. Preoperative evaluation and postoperative urinary drainage are important.

Efficacy of electroacupuncture therapy in patients with functional anorectal pain: study protocol for a multicenter randomized controlled trial.

BACKGROUND: Some Chinese scholars have initially explored the efficacy of electroacupuncture at Baliao acupoint in patients with functional anorectal pain (FAP). However, their studies are performed in a single center, or the sample size is small. Therefore, we aim to further explore the efficacy of electroacupuncture at Baliao acupoint on the treatment of FAP. METHODS: In this multicenter randomized controlled trial, 136 eligible FAP patients will be randomly allocated into an electroacupuncture group or sham electroacupuncture group at a 1:1 ratio. This trial will last for 34 weeks, with 2 weeks of baseline, 4 weeks and 8 weeks of treatment, and 1, 3, and 6 months of follow-up. Outcome assessors and statisticians will be blind. The primary outcome will be clinical treatment efficacy, and secondary outcomes will be pain days per month, quality of life, psychological state assessment, anorectal manometry, pelvic floor electromyography, and patient satisfaction. DISCUSSION: Results of this trial will be contributed to further clarify the value of electroacupuncture at Baliao acupoint as a treatment for FAP in the clinic. TRIAL REGISTRATION: This trial has been registered in Chinese Clinical Trial Registry  https://www.chictr.org.cn/  (ChiCTR2300069757) on March 24, 2023.

Infection risk reduction with povidone-iodine rectal disinfection prior to transrectal prostate biopsy: an updated systematic review and meta-analysis.

BACKGROUND: To prevent infectious complications after transrectal ultrasound-guided prostate biopsy (TRUS-PB), some studies have investigated the efficacy of rectal disinfection using povidone-iodine (PI) and antibiotic prophylaxis (AP). OBJECTIVE: To summarize available data and compare the efficacy of rectal disinfection using PI with non-PI methods prior to TRUS-PB. EVIDENCE ACQUISITION: Three databases were queried through November 2023 for randomized controlled trials (RCTs) analyzing patients who underwent TRUS-PB. We compared the effectiveness of rectal disinfection between PI groups and non-PI groups with or without AP. The primary outcomes of interest were the rates of overall infectious complications, fever, and sepsis. Subgroups analyses were conducted to assess the differential outcomes in patients using fluoroquinolone groups compared to those using other antibiotics groups. EVIDENCE SYNTHESIS: We included ten RCTs in the meta-analyses. The overall rates of infectious complications were significantly lower when rectal disinfection with PI was performed (RR 0.56, 95% CI 0.42-0.74, p < 0.001). Compared to AP monotherapy, the combination of AP and PI was associated with significantly lower risk of infectious complications (RR 0.54, 95% CI 0.40-0.73, p < 0.001) and fever (RR 0.47, 95% CI 0.30-0.75, p = 0.001), but not with sepsis (RR 0.49, 95% CI 0.23-1.04, p = 0.06). The use of fluoroquinolone antibiotics was associated with a lower risk of infectious complications and fever compared to non-FQ antibiotics. CONCLUSION: Rectal disinfection with PI significantly reduces the rates of infectious complications and fever in patients undergoing TRUS-PB. However, this approach does not show a significant impact on reducing the rate of sepsis following the procedure.

Oral-to-rectum microbial transmission in orthopedic patients without a history of intestinal disorders.

The enrichment of oral taxa in the gut has recently been reported as a notable alteration in the microbial balance in patients with intestinal disorders. However, translocation in populations without such diseases remains controversial. In this study, we examined 49 pairs of tongue and rectal samples collected from orthopedic patients without a history of intestinal disorders to verify the presence of oral taxa in the rectal microbiota. The bacterial composition of each sample was determined using 16S rRNA gene sequencing and amplicon sequence variant (ASV) analysis. Although the bacterial compositions of the tongue and rectal microbiota were distinctly different, tongue ASVs were detected in 67.3% of the participants and accounted for 0.0%-9.37% of the rectal microbiota. Particularly, Streptococcus salivarius, Fusobacterium nucleatum, and Streptococcus parasanguinis were abundant in the rectal microbiota. According to the network analysis, tongue taxa, such as S. salivarius and S. parasanguinis, formed a cohabiting group with Klebsiella pneumoniae and Alistipes finegoldii in the rectal microbiota. The total abundance of tongue ASVs in the rectal microbiota was significantly higher in participants with older age, hypertension, and proton pump inhibitor (PPI) use. Our study presents an extensive translocation of oral taxa to the rectum of a population without intestinal disorders and suggests that aging, hypertension, and PPI use are associated with an increased abundance of oral taxa and potential pathogenic bacteria in the rectal microbiota.

The efficacy and safety of short-course radiotherapy followed by sequential chemotherapy and Cadonilimab for locally advanced rectal cancer: a protocol of a phase II study.

BACKGROUND: For patients with locally advanced rectal cancer (LARC), total neoadjuvant therapy (TNT), namely, intensifying preoperative treatment through the integration of radiotherapy and systemic chemotherapy before surgery, was commonly recommended as the standard treatment. However, the risk of distant metastasis at 3 years remained higher than 20%, and the complete response (CR) rate was less than 30%. Several clinical trials had suggested a higher complete response rate when combining single-agent immunotherapy with short-course radiotherapy (SCRT). The CheckMate 142 study had shown encouraging outcomes of dual immunotherapy and seemingly comparable toxicity for CRC compared with single-agent immunotherapy in historical results. Therefore, dual immunotherapy might be more feasible in conjunction with the TNT paradigm of SCRT. We performed a phase II study to investigate whether the addition of a dual immune checkpoint inhibitor bispecific antibody, Cadonilimab, to SCRT combined with chemotherapy might further increase the clinical benefit and prognosis for LARC patients. METHODS: This single-arm, multicenter, prospective, phase II study included patients with pathologically confirmed cT3-T4N0 or cT2-4N + rectal adenocarcinoma with an ECOG performance score of 0 or 1. Bispecific antibody immunotherapy was added to SCRT combined with chemotherapy. Patients enrolled would be treated with SCRT (25 Gy in five fractions over 1 week) for the pelvic cavity, followed by 4 cycles of CAPOX or 6 cycles of mFOLFOX and Cadonilimab. The primary endpoint was the CR rate, which was the ratio of the pathological CR rate plus the clinical CR rate. The secondary endpoints included local-regional control, distant metastasis, disease-free survival, overall survival, toxicity profile, quality of life and functional outcome of the rectum. To detect an increase in the complete remission rate from 21.8% to 40% with 80% power, 50 patients were needed. DISCUSSION: This study would provide evidence on the efficacy and safety of SCRT plus bispecific antibody immunotherapy combined with chemotherapy as neoadjuvant therapy for patients with LARC, which might be used as a candidate potential therapy in the future. TRIAL REGISTRATION: This phase II trial was prospectively registered at ClinicalTrials.gov, under the identifier NCT05794750.

Evaluation of anorectal function using real-time tissue elastography before and after preoperative chemoradiotherapy.

PURPOSE: This study aimed to clarify the relationship between changes in elasticity and anorectal function before and after chemoradiotherapy. METHODS: This is a single-center prospective cohort study (Department of Surgical Oncology, The University of Tokyo). We established a technique to quantify internal anal sphincter hardness as elasticity using transanal ultrasonography with real-time tissue elastography. Twenty-seven patients with post-chemoradiotherapy rectal cancer during 2019-2022 were included. Real-time tissue elastography with transanal ultrasonography was performed before and after chemoradiotherapy to measure internal anal sphincter hardness as "elasticity" (hardest (0) to softest (255); decreased elasticity indicated sclerotic changes). The relationship between the increase or decrease in elasticity pre- and post-chemoradiotherapy and the maximum resting pressure, maximum squeeze pressure, and Wexner score were the outcome measures. RESULTS: A decrease in elasticity was observed in 16/27 (59.3%) patients after chemoradiotherapy. Patients with and without elasticity decrease after chemoradiotherapy comprised the internal anal sphincter sclerosis and non-sclerosis groups, respectively. The maximum resting pressure post-chemoradiotherapy was significantly high in the internal anal sphincter sclerosis group (63.0 mmHg vs. 47.0 mmHg), and a majority had a worsening Wexner score (60.0% vs. 18.2%) compared with that of the non-sclerosis group. Decreasing elasticity (internal anal sphincter sclerosis) correlated with a higher maximum resting pressure (r = 0.36); no correlation was observed between the degree of elasticity change and maximum squeeze pressure. CONCLUSION: Internal anal sphincter sclerosis due to chemoradiotherapy may correlate to anorectal dysfunction.

Evaluation of the effect of prostate diameters on erectile dysfunction in patients who underwent low-anterior resection.

OBJECTIVE: Male erectile dysfunction is an important complication of rectal surgery. In this research, the effect of prostate dimensions on the development of postoperative erectile dysfunction in patients diagnosed with mid-rectum adenocarcinoma who underwent low anterior resection (LAR) is examined. PATIENTS AND METHODS: Thirty-one male patients diagnosed as mid-rectal adenocancer were included. The International Index of Erectile Function (IIEF) questionnaire was used to determine the patients' pre and postoperative erectile dysfunction levels, and the level of relationship between the change in these IIEF scores and prostate measurements determined by computed tomography were evaluated. RESULTS: There were statistically significant differences between IIEF index score and anterior posterior (AP) and transverse (TR) measurements (p≤0.001; p≤0.001), but no statistically significant difference was found between craniocaudal (CC) measurement values (p=0.169). CONCLUSIONS: The risk of nerve injury will be higher in those with a small prostate transverse diameter. Intraoperative nerve monitoring should be recommended primarily in younger patient groups.