An artificial intelligence-based nerve recognition model is useful as surgical support technology and as an educational tool in laparoscopic and robot-assisted rectal cancer surgery.

BACKGROUND: Artificial intelligence (AI) has the potential to enhance surgical practice by predicting anatomical structures within the surgical field, thereby supporting surgeons' experiences and cognitive skills. Preserving and utilising nerves as critical guiding structures is paramount in rectal cancer surgery. Hence, we developed a deep learning model based on U-Net to automatically segment nerves. METHODS: The model performance was evaluated using 60 randomly selected frames, and the Dice and Intersection over Union (IoU) scores were quantitatively assessed by comparing them with ground truth data. Additionally, a questionnaire was administered to five colorectal surgeons to gauge the extent of underdetection, overdetection, and the practical utility of the model in rectal cancer surgery. Furthermore, we conducted an educational assessment of non-colorectal surgeons, trainees, physicians, and medical students. We evaluated their ability to recognise nerves in mesorectal dissection scenes, scored them on a 12-point scale, and examined the score changes before and after exposure to the AI analysis videos. RESULTS: The mean Dice and IoU scores for the 60 test frames were 0.442 (range 0.0465-0.639) and 0.292 (range 0.0238-0.469), respectively. The colorectal surgeons revealed an under-detection score of 0.80 (± 0.47), an over-detection score of 0.58 (± 0.41), and a usefulness evaluation score of 3.38 (± 0.43). The nerve recognition scores of non-colorectal surgeons, rotating residents, and medical students significantly improved by simply watching the AI nerve recognition videos for 1 min. Notably, medical students showed a more substantial increase in nerve recognition scores when exposed to AI nerve analysis videos than when exposed to traditional lectures on nerves. CONCLUSIONS: In laparoscopic and robot-assisted rectal cancer surgeries, the AI-based nerve recognition model achieved satisfactory recognition levels for expert surgeons and demonstrated effectiveness in educating junior surgeons and medical students on nerve recognition.

Prognosis and predictive factors of conversion surgery for initially unresectable advanced colorectal cancer.

PURPOSE: The aim of this study was to report the outcomes of conversion surgery for initially unresectable advanced colorectal cancer and to identify factors that enable successful conversion surgery. METHODS: We compared the outcomes of patients with colorectal cancer with distant metastases, including extrahepatic metastases, who underwent upfront surgery, neoadjuvant chemotherapy, conversion surgery, and chemotherapy only at our department from 2007 to 2020. In addition, factors influencing the achievement of conversion surgery in patients who were initially unresectable were examined in univariate and multivariate analyses. RESULTS: Of 342 colorectal cancer patients with distant metastases treated during the study period, 239 were judged to be initially unresectable, and 17 (conversion rate: 7.1%) underwent conversion surgery. The prognosis for the conversion surgery group was better than that of the chemotherapy only group but worse than that of the upfront surgery group. In the conversion surgery group, the recurrence-free survival after resection was significantly shorter than that upfront surgery group and neoadjuvant chemotherapy group, and no patients have been cured. Among patients who were initially unresectable, left-sided primary cancer and normal CA19-9 level were identified as independent factors contributing to the achievement of conversion surgery in a multivariate analysis. CONCLUSIONS: Although relapse after conversion surgery is common, and no patients have been cured thus far, overall survival was better in comparison to patients who received chemotherapy only. Among unresectable cases, patients with left-sided primary cancer and normal CA19-9 levels are likely to be candidates for conversion surgery.

Treatment outcomes in non-occlusive mesenteric ischemia and post-treatment return to social activities.

PURPOSE: To investigate the treatment outcomes of patients with non-occlusive mesenteric ischemia (NOMI) at our institution, we focused on their post-treatment return to social activities. METHODS: This study included patients with suspected NOMI who were referred to our department between 2011 and 2023. In-hospital mortality was also investigated as a prognostic factor. The Glasgow-Pittsburgh Outcome Categories (GPOC) score was used to evaluate the return to social activities. The relationship between in-hospital mortality and GPOC scores and patient background and treatment factors was examined. RESULTS: Eighty-two patients were included in the study. Among them, 54 (65.9%) died during hospitalization. Only 9 patients (11%) returned to their social activities. In the multivariate analysis, non-surgical management was found to be the only independent factor for in-hospital mortality. Positive portal venous gas on computed tomography, no open abdomen, no pre-onset catecholamine administration, platelet count < 100,000/µL, lactate level < 5 mmol/L, APTT < 46 s, and Sequential Organ Failure Assessment score < 11 were factors significantly associated with an increased likelihood of return to social activities. CONCLUSION: This is the first study to assess the post-treatment return to social activities among patients with NOMI. Our findings highlight the concerning reality that survivors may face prolonged dependence on medical care.

[A Case of Primary Duodenal Adenocarcinoma in the Third Portion Treated with Partial Duodenectomy and Adjuvant Chemotherapy].

A 69-year-old man was referred for vomiting. CT and upper gastrointestinal endoscopy revealed a circumferential stenotic lesion in the third portion of the duodenum, and partial duodenectomy and lymph node dissection were performed for the diagnosis of duodenal adenocarcinoma. The histopathological diagnosis was pT3, pN0, pStage ⅡA(UICC 8th)well differentiated tubular adenocarcinoma. The patient was treated with FOLFOX as adjuvant chemotherapy and is alive 2 years and 4 months postoperatively without recurrence. Primary duodenal adenocarcinoma in the third portion is rare, and further case experience is required for selection of the operation and adjuvant therapy.

[A Case of Resection of Overlapping Ascending Colon Cancer and Primary Malignant Lymphoma of the Cecum].

The patient was a 90-year-old man. He was referred to our department with a diagnosis of ascending colon cancer after lower gastrointestinal endoscopy for a positive stool occult blood test. Lower gastrointestinal endoscopy revealed a type 1 tumor 30 mm in the ascending colon and a type 3 tumor 50 mm in the cecum. Biopsy revealed Group 5(tub1)for the ascending colon lesion, but Group 2 for the cecum lesion. The patient was clinically diagnosed as having overlapping ascending colon cancer and cecum cancer, and a right hemicolectomy of the colon was performed. Histopathological examination revealed ascending colon cancer and primary malignant lymphoma of the cecum.

[A Case of Postoperative Lymph Node Metastatic Recurrence of Ascending Colon Cancer Invading the Primary Branch of Superior Mesenteric Artery during Hemodialysis].

A 58-year-old man with chronic renal disease underwent ileo-cecal resection with lymph node dissection for cancer of the ascending colon at his previous physician. The pathological diagnosis was pT3N0M0, pStage Ⅱa. One year and 7 months after surgery, he was diagnosed with local and lymph node recurrence and referred to our department. Contrast- enhanced CT revealed that an irregular nodal shadow 25 mm in size adjacent to the superior mesenteric artery and the transvers part of duodenum, which was suspicious for lymph node recurrence. We regarded this patient as marginally resectable and neoadjuvant treatment was considered, but because the patient was on dialysis, we decided to operate without pre-operative treatment. Surgical findings showed invasion of a recurrent lymph node into a primary branch of the superior mesenteric artery and vein. We temporarily blocked these vessels and cut off these vessels after checking that blood flow in the intestine was maintained by intravenous injection of ICG. The lymph node was also invading the uncinate process of the pancreas and the transvers part of duodenum, we performed partial resection of those organs. Pathology revealed no tumor exposure on the dissected surface and R0 resection was achieved. The patient received 5 courses of postoperative folinate/ uracil/tegafur therapy and is alive 1 year postoperatively without recurrence.

Response prediction of neoadjuvant chemoradiation therapy in locally advanced rectal cancer using CT-based fractal dimension analysis.

OBJECTIVES: There are individual variations in neo-adjuvant chemoradiation therapy (nCRT) in patients with locally advanced rectal cancer (LARC). No reliable modality currently exists that can predict the efficacy of nCRT. The purpose of this study is to assess if CT-based fractal dimension and filtration-histogram texture analysis can predict therapeutic response to nCRT in patients with LARC. METHODS: In this retrospective study, 215 patients (average age: 57 years (18-87 years)) who received nCRT for LARC between June 2005 and December 2016 and underwent a staging diagnostic portal venous phase CT were identified. The patients were randomly divided into two datasets: a training set (n = 170), and a validation set (n = 45). Tumor heterogeneity was assessed on the CT images using fractal dimension (FD) and filtration-histogram texture analysis. In the training set, the patients with pCR and non-pCR were compared in univariate analysis. Logistic regression analysis was applied to identify the predictive value of efficacy of nCRT and receiver operating characteristic analysis determined optimal cutoff value. Subsequently, the most significant parameter was assessed in the validation set. RESULTS: Out of the 215 patients evaluated, pCR was reached in 20.9% (n = 45/215) patients. In the training set, 7 out of 37 texture parameters showed significant difference comparing between the pCR and non-pCR groups and logistic multivariable regression analysis incorporating clinical and 7 texture parameters showed that only FD was associated with pCR (p = 0.001). The area under the curve of FD was 0.76. In the validation set, we applied FD for predicting pCR and sensitivity, specificity, and accuracy were 60%, 89%, and 82%, respectively. CONCLUSION: FD on pretreatment CT is a promising parameter for predicting pCR to nCRT in patients with LARC and could be used to help make treatment decisions. KEY POINTS: • Fractal dimension analysis on pretreatment CT was associated with response to neo-adjuvant chemoradiation in patients with locally advanced rectal cancer. • Fractal dimension is a promising biomarker for predicting pCR to nCRT and may potentially select patients for individualized therapy.

Hepatobiliary contrast uptake patterns on gadoxetic acid-enhanced MRI in liver metastases from pancreatic ductal adenocarcinoma: can it predict prognosis?

OBJECTIVES: To evaluate the relationship between the patterns of hepatobiliary phase (HBP) contrast uptake in liver metastases on gadoxetic acid-enhanced MR imaging and overall survival (OS) in patients with pancreatic ductal adenocarcinoma (PDAC). METHODS: This retrospective study was approved by our institutional review board and written informed consent was waived. A total of 57 patients (30 men and 27 women; age range, 46-92 years; mean age, 64.9 ± 9.2 years) with PDAC and liver metastasis who had undergone gadoxetic acid-enhanced MR imaging were included. The internal morphologies of the nodules were classified as heterogeneous or homogeneous on HBP images (20 min). During patient-by-patient analysis, patients with both patterns of nodules were classified as belonging to the heterogeneous group. Kaplan-Meier analysis and log-rank test were conducted for univariate analysis and Cox proportional hazards regression was conducted for multivariate analysis to evaluate prognostic factors for OS in patients with PDAC and liver metastasis. RESULTS: A total of 199 liver metastases were analyzed, among which 138 nodules (69%) demonstrated heterogeneous hypointensity, while 61 nodules (31%) demonstrated homogeneous hypointensity. Homogeneous hypointense nodules were encountered in 18 patients (32%; homogeneous group), heterogeneous in 29 patients (51%), and both patterns co-existed in 10 patients (17%; heterogeneous group). The heterogeneous group exhibited lower OS rates than the homogeneous group (mean OS, 48.5 months vs 23.9 months; p = 0.032). CONCLUSIONS: Hepatobiliary contrast uptake pattern in liver metastasis on HBP images can be a potential imaging biomarker to predict OS in patients with PDAC and liver metastasis. KEY POINTS: • Majority of the liver metastases were heterogeneous (69%) after gadoxetic acid-enhanced MR imaging. • Patients with heterogeneous hypointense nodules demonstrated lower overall survival rate. • Hepatobiliary contrast uptake pattern in liver metastasis is possibly associated with patients' prognosis.

Low keV portal venous phase as a surrogate for pancreatic phase in a pancreatic protocol dual-energy CT: feasibility, image quality, and lesion conspicuity.

OBJECTIVE: To assess the feasibility of a proposed pancreatic protocol CT generated from portal-venous phase (PVP) dual-energy CT (DECT) acquisition and its impact on image quality, lesion conspicuity, and arterial visualization/involvement. METHODS: We included 111 patients (mean age, 66.8 years) who underwent pancreatic protocol DECT (pancreatic phase, PP, and PVP). The original DECT acquisition was used to create two data sets-standard protocol (50 keV PP/65 keV PVP) and proposed protocol (40 keV/65 keV PVP). Three reviewers evaluated the two data sets for image quality, lesion conspicuity, and arterial visualization/involvement using a 5-point scale. The signal-to-noise ratio (SNR) of pancreas and lesion-to-pancreas contrast-to-noise ratio (CNR) was calculated. Qualitative scores, quantitative parameters, and dose-length product (DLP) were compared between standard and proposed protocols. RESULTS: The image quality, SNR of pancreas, and lesion-to-pancreas CNR of the standard and proposed protocol were comparable (p = 0.11-1.00). Lesion conspicuity was comparable between the standard and proposed protocols for pancreatic ductal adenocarcinoma (p = 0.55) and pancreatic cysts (p = 0.28). The visualization of larger arteries and arterial involvement were comparable between the two protocols (p = 0.056-1.00) while the scores were higher for smaller vessels in the standard protocol (p < 0.0001-0.0015). DLP of the proposed protocol (670.4 mGy·cm) showed a projected 42% reduction than the standard protocol (1145.9 mGy·cm) (p < 0.0001). CONCLUSION: Pancreatic protocol CT generated from a single PVP DECT acquisition is feasible and could potentially be an alternative to the standard pancreatic protocol with PP and PVP. KEY POINTS: • The lesion conspicuity for focal pancreatic lesions was comparable between the proposed protocol and standard dual-phase pancreatic protocol CT. • Qualitative and quantitative image assessments were almost comparable between two protocols. • The radiation dose of a proposed protocol showed a projected 42% reduction from the conventional protocol.

Computed tomography-derived biomarker for predicting the treatment response to neoadjuvant chemoradiotherapy of rectal cancer.

BACKGROUND: Malignant tumor essentially implies structural heterogeneity. Analysis of medical imaging can quantify this structural heterogeneity, which can be a new biomarker. This study aimed to evaluate the usefulness of texture analysis of computed tomography (CT) imaging as a biomarker for predicting the therapeutic response of neoadjuvant chemoradiotherapy (nCRT) for locally advanced rectal cancer. METHODS: We enrolled 76 patients with rectal cancer who underwent curative surgery after nCRT. Texture analyses (Fractal analysis and Histogram analysis) were applied to contrast-enhanced CT images, and fractal dimension (FD), skewness, and kurtosis of the tumor were calculated. These CT-derived parameters were compared with the therapeutic response and prognosis. RESULTS: Forty-six of 76 patients were diagnosed as clinical responders after nCRT. Kurtosis was significantly higher in the responders group than in the non-responders group (4.17 ± 4.16 vs. 2.62 ± 3.19, p = 0.04). Nine of 76 patients were diagnosed with pathological complete response (pCR) after surgery. FD of the pCR group was significantly lower than that of the non-pCR group (0.90 ± 0.12 vs. 1.01 ± 0.12, p = 0.009). The area under the receiver-operating characteristics curve of tumor FD for predicting pCR was 0.77, and the optimal cut-off value was 0.84 (accuracy; 93.4%). Furthermore, patients with lower FD tumors tended to show better relapse-free survival and disease-specific survival than those with higher FD tumors (5-year, 80.8 vs. 66.6%, 94.4 vs. 80.2%, respectively), although it was not statistically significant (p = 0.14, 0.11). CONCLUSIONS: CT-derived texture parameters could be potential biomarkers for predicting the therapeutic response of rectal cancer.

Development of imaging biomarker for esophageal cancer using intravoxel incoherent motion MRI.

BACKGROUND: Intravoxel incoherent motion MRI (IVIM-MRI) can quantify micro-perfusion at the capillary level in the tissue. The purpose of this study is to measure tumor perfusion using IVIM-MRI, and evaluate its value as a biomarker to predict prognosis in esophageal squamous cell carcinoma (ESCC) patients. METHODS: 109 ESCC patients (93 men and 16 women; median age: 72) who underwent IVIM-MRI prior to treatment between February 2018 and August 2020 were retrospectively investigated. Both mean apparent diffusion coefficient (ADC) value and mean perfusion-related parameter (PP) value of the primary tumor were measured using three b values of 0, 400, and 1000 s/mm2 based on the IVIM model. We analyzed associations of these parameters with clinical stage and disease-specific survival (DSS). RESULTS: Lower ADC and PP values of the tumor were significantly associated with the higher clinical T stage (p < 0.0001, p < 0.0001, respectively). In Kaplan-Meier analyses, patients with lower PP value tumors (< 18.94, median) had significantly worse DSS (p < 0.0001), while tumor ADC value did not show a significant correlation with DSS. In a multivariate analysis, PP value of the tumor was an independent prognostic factor for DSS (p = 0.0027). CONCLUSIONS: Quantification of tumor perfusion using IVIM-MRI can be a non-invasive prognostic biomarker of ESCC, reflecting clinical stage and survival.

Clinical utility of transanal indocyanine green near-infrared fluorescence imaging for evaluation of colorectal anastomotic perfusion.

BACKGROUND: Although indocyanine green (ICG) fluorescence imaging has been reported to be useful for assessing colorectal perfusion, unstable quantification remains an issue. We performed ICG fluorescence observation from the luminal side and examined the usefulness of the transanal approach. METHODS: A total of 69 patients who underwent left-side colon surgery were enrolled in this cohort study. After the anastomosis had been constructed, ICG 0.2 mg/kg was injected intravenously. The anastomotic site was then observed by a scope inserted transanally. The following items were examined in the areas of the anastomotic site with the highest- and lowest-fluorescence intensity: maximum fluorescence (Fmax), time from ICG injection to Fmax (Tmax), time from start of dyeing to Fmax (ΔT), and the contrast pattern of the mucosa. RESULTS: Anastomotic leakage (AL) occurred in nine cases. Tmax and ΔT values of the lowest-fluorescence area in the distal intestine showed significant differences in the cases with AL (P = 0.015 and P = 0.040, respectively). Regarding the contrast pattern of the mucosa of the lowest-fluorescence area in the proximal and distal intestine, the patients in whom the vessels were not depicted in the area had a significantly higher incidence of AL than those in whom vessels were depicted in the area (P = 0.031 and P = 0.030, respectively). Some of the areas in which vessels were not depicted by ICG fluorescence observation from the luminal side corresponded to the points of leakage. There were heterogeneous changes that might not be grasped by observation from the serosal side. CONCLUSION: Transanal ICG fluorescence imaging can evaluate perfusion over the entire circumference of the anastomosis in detail and aid in assessing the risk of AL. Therefore, the examination of the detailed low-perfusion area enables us to take measures for AL and to search for safer operative managements.

[Long-Term Control of Metastatic Colon Cancer by Chemotherapy in a Patient on Hemodialysis].

A 54-year-old man receiving dialysis for diabetic nephropathy underwent surgery for sigmoid cancer. Nine months later, he was diagnosed with multiple liver metastases. He underwent 2 courses of FOLFIRI plus panitumumab(Pmab)as first-line therapy, 15courses of capecitabine plus bevacizumab(Bmab)as second-line therapy, and 27 courses of Pmab as third-line therapy. He developed various complications throughout the disease course, such as heart disease, diabetic gangrene in both legs, and abscess of liver metastasis. The tumor marker levels after each event were higher than the previous event and subsequently decreased with the resumption of chemotherapy. However, after 27 courses of Pmab, his liver and para-aortic lymph node metastases exacerbated, and he ultimately died from a poor general condition at 42 months after the initial recurrence of liver metastasis. Evidence regarding the safety and pharmacokinetics of chemotherapy in dialysis patients is insufficient at present. Herein, we report a case of metastatic colon cancer in a patient on hemodialysis along with a literature review.

Heterogeneity of Glucose Metabolism in Esophageal Cancer Measured by Fractal Analysis of Fluorodeoxyglucose Positron Emission Tomography Image: Correlation between Metabolic Heterogeneity and Survival.

BACKGROUND: Intratumoral heterogeneity is a well-recognized characteristic feature of cancer. The purpose of this study is to assess the heterogeneity of the intratumoral glucose metabolism using fractal analysis, and evaluate its prognostic value in patients with esophageal squamous cell carcinoma (ESCC). METHODS: 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) studies of 79 patients who received curative surgery were evaluated. FDG-PET images were analyzed using fractal analysis software, where differential box-counting method was employed to calculate the fractal dimension (FD) of the tumor lesion. Maximum standardized uptake value (SUVmax) and FD were compared with overall survival (OS). RESULTS: The median SUVmax and FD of ESCCs in this cohort were 13.8 and 1.95, respectively. In univariate analysis performed using Cox's proportional hazard model, T stage and FD showed significant associations with OS (p = 0.04, p < 0.0001, respectively), while SUVmax did not (p = 0.1). In Kaplan-Meier analysis, the low FD tumor (<1.95) showed a significant association with favorable OS (p < 0.0001). In wthe multivariate analysis among TNM staging, serum tumor markers, FD, and SUVmax, the FD was identified as the only independent prognostic factor for OS (p = 0.0006; hazards ratio 0.251, 95% CI 0.104-0.562). CONCLUSION: Metabolic heterogeneity measured by fractal analysis can be a novel imaging biomarker for survival in patients with ESCC.

[A Case of Rectal Metastasis from Breast Cancer Diagnosed Two Years after Surgery].

We report a case of rectal metastasis from breast cancer.Colorectal metastasis from breast cancer is sometimes difficult to diagnose before surgery.A transanal needle biopsy was thought to be useful for a diagnosis and selection of treatment method.

[Usefulness of FDG-PET for superficial esophageal squamous cell carcinoma].

We investigated the usefulness of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) for superficial esophageal squamous cell carcinoma after resection via endoscopic submucosal dissection (ESD). Our case study included 37 patients and 49 tumors resected via ESD in our hospital between January 2012 and December 2013. Histopathological diagnosis confirmed squamous cell carcinoma in all cases. Tumors located near the esophago cardiac junction were excluded. We investigated retrospectively whether the standardized uptake value (SUV) obtained by using FDG-PET could be the criterion to decide whether to perform ESD. At first, the tumor was examined via endoscopy. If tumor depth (T status)was less than cSM1, we performed ESD. When the tumor depth was less than pSM1, no infiltration of the vessel or lymph duct was observed, and the surgical margin was free; therefore, we did not perform any further therapy. On the other hand, we measured the SUV obtained via FDG-PET. The cut-off value was set as 3.0 based on the correlation between the SUV and tumor depth. We investigated if SUV<.0 could be the criterion for further therapy after ESD. In our results, the sensitivity was 95%, specificity was 67%, and accuracy was 90%. The SUV also helped to identify the malignancy of the superficial esophageal cancer and could help to decide whether ESD should be undertaken.

Peripherally inserted central catheter securement with cyanoacrylate glue and bloodstream infection: A retrospective cohort study.

BACKGROUND: Treatment via a peripherally inserted central venous catheter is important for anticancer treatment, perioperative management, and nutrition management. In this study, we aimed to investigate the usefulness of cyanoacrylate glue (CG) in managing peripherally inserted central venous catheters in adults. METHODS: This retrospective cohort study enrolled 411 adults requiring a central venous catheter for treatment in the Chiba University Esophageal-Gastro-Intestinal Surgery department between January 2021 and October 2022. The preventive effect of CG in reducing adverse events, including infection, tip migration, and thrombus formation, was evaluated by reviewing electronic medical records, chest radiographs, and contrast-enhanced computed tomography scans. RESULTS: CG and other dressings were used in 158 (CG group) and 253 (control group) patients, respectively. The incidence of catheter infection based on the clinical course was lower in the CG group (3.2%) than in the control group (9.1%; P = 0.03). However, cases of infection confirmed by blood or catheter cultures did not differ between the CG (1.3%) and control (1.9%) groups (P = 1.0). Chest radiographs revealed that catheter tip migration (mean ± SD) was lesser in the CG group (8.2 ± 6.7 mm) than in the control group (15.0 ± 15.8 mm; P < 0.01). There were two cases of venous thrombus formation in the control group. CONCLUSION: In a population dominated by esophago-gastroenterological malignancy, peripherally inserted central catheter securement via CG was associated with decreased catheter removal because of suspected catheter infection. Further research on larger cohorts is needed to determine if other adverse events decrease following peripherally inserted central catheter securement via CG.

A Randomized Trial of Ionic Silver Dressing to Reduce Surgical Site Infection After Gastrointestinal Surgery.

Objective: To determine whether Aquacel Ag Hydrofiber dressings containing ionic silver are superior to film dressings for preventing superficial surgical site infections (SSI) in patients undergoing elective gastrointestinal surgery. Background: Multiple clinical trials have assessed the effectiveness of silver-containing wound dressings; however, systematic reviews failed to find any advantages of these dressings and concluded that there was insufficient evidence to indicate that they prevented wound infections. This study aimed to evaluate the efficacy of Aquacel Ag Hydrofiber dressings for preventing superficial SSIs in patients undergoing gastrointestinal surgery. Methods: Patients undergoing elective gastrointestinal surgery were randomly assigned to receive either Aquacel Ag Hydrofiber (study group) or film dressings (control group). The primary end point was superficial SSI within 30 days after surgery (UMIN Clinical Trials Registry ID: 000043081). Results: A total of 865 patients (427 study group, 438 control group) were qualified for primary end-point analysis. The overall rate of superficial SSIs was significantly lower in the study group than in the control group (6.8% vs 11.4%, P = 0.019). There was no significant difference in superficial SSI rates between the groups in patients undergoing upper gastrointestinal surgery; however, the rate was significantly lower in the study group in patients undergoing lower gastrointestinal surgery (P = 0.042). Multivariate analysis identified Aquacel Ag Hydrofiber dressings as an independent factor for reducing superficial SSIs (odds ratio, 0.602; 95% confidence interval, 0.367-0.986; P = 0.044). Conclusions: Aquacel Ag Hydrofiber dressings can reduce superficial SSIs compared to film dressings in patients undergoing elective gastrointestinal surgery, especially lower gastrointestinal surgery.

A case of rectal metastasis of prostate cancer mimicking extramural growth-type rectal tumor.

Rectal metastases of prostate cancer are rare and may be difficult to diagnose. In this report, we describe a case in which an extramural growth-type rectal tumor was resected and pathologically diagnosed as prostate cancer metastasis. A 70-year-old man on hormone therapy for prostate cancer with seminal vesicle invasion and pelvic lymph node metastasis was referred to our department after an imaging scan showed an extramural growth-type rectal tumor. Endoscopic ultrasound-guided fine needle aspiration was considered for diagnosis, but the patient preferred an early resection without the exam, so surgery was performed. Histopathological examination revealed that the lesion was in the adventitia of the rectum and metastasis of prostate cancer. Metastatic lesions of prostate cancer are not indicated for resection. A detailed preoperative study with the possibility of prostate cancer metastasis in mind is necessary because it is relevant to choosing the treatment strategy.