Incidence and molecular characteristics of deficient mismatch repair conditions across nine different tumors and identification of germline variants involved in Lynch-like syndrome.

BACKGROUND: Based on molecular characteristics, deficient DNA mismatch repair (dMMR) solid tumors are largely divided into three categories: somatically MLH1-hypermethylated tumors, Lynch syndrome (LS)-associated tumors, and Lynch-like syndrome (LLS)-associated tumors. The incidence of each of these conditions and the corresponding pathogenic genes related to LLS remain elusive. METHODS: We identified dMMR tumors in 3609 tumors from 9 different solid organs, including colorectal cancer, gastric cancer, small-bowel cancer, endometrial cancer, ovarian cancer, upper urinary tract cancer, urinary bladder cancer, prostate cancer, and sebaceous tumor, and comprehensively summarized the characterization of dMMR tumors. Characterization of dMMR tumors were performed as loss of at least one of MMR proteins (MLH1, MSH2, MSH6, and PMS2), by immunohistochemistry, followed by MLH1 promotor methylation analysis and genetic testing for MMR genes where appropriate. Somatic variant analysis of MMR genes and whole exome sequencing (WES) were performed in patients with LLS. RESULTS: In total, the incidence of dMMR tumors was 5.9% (24/3609). The incidence of dMMR tumors and the proportion of the three categorized dMMR tumors varied considerably with different tumor types. One to three likely pathogenic/pathogenic somatic MMR gene variants were detected in 15 out of the 16 available LLS tumors. One patient each from 12 patients who gave consent to WES demonstrated non-MMR germline variants affect function (POLQ or BRCA1). CONCLUSIONS: Our data regarding the LS to LLS ratio would be useful for genetic counseling in patients who are suspected to have LS, though the genetic backgrounds for the pathogenesis of LLS need further investigation.

Short- and Long-Term Outcomes of Neoadjuvant Chemoradiotherapy Followed by Pancreatoduodenectomy in Elderly Patients with Resectable and Borderline Resectable Pancreatic Cancer: A Retrospective Study.

Background: The efficacy of neoadjuvant chemoradiotherapy (NACRT) followed by pancreatoduodenectomy (PD) in elderly patients with pancreatic ductal adenocarcinoma (PDAC) remains unclear. Methods: This retrospective analysis of prospectively collected data examined the effect of NACRT followed by PD in elderly patients with PDAC. A total of 112 patients with resectable (R-) and borderline resectable (BR-) PDAC, who were planned for PD and received NACRT between 2009 and 2022, were assessed. Changes induced by NACRT, surgical outcomes, nutritional status, renal and endocrine functions, and prognosis were compared between elderly (≥75 years, n = 43) and non-elderly (<75 years, n = 69) patients over two years following PD. Results: Completion and adverse event rates during NACRT, nutritional status, renal function, endocrine function over two years postoperatively, and prognosis did not significantly differ between the two groups. Low prognostic index after NACRT and the absence of postoperative adjuvant chemotherapy may be adverse prognostic indicators for elderly patients undergoing NACRT for R- and BR-PDAC. Conclusions: Despite a higher incidence of postoperative complications, NACRT followed by PD can be safely performed in elderly patients, resulting in a prognosis similar to that in non-elderly patients.

A combined score for predicting clinically relevant postoperative pancreatic fistula based on inflammatory parameters and drainage fluid culture results on postoperative day 3.

BACKGROUND: Clinically relevant postoperative pancreatic fistula (CR-POPF) after pancreatic resection can lead to severe postoperative complications. POPF is defined based on postoperative day (POD) 3 drainage fluid amylase level. POPF correlates with inflammatory parameters as well as drainage fluid bacterial infection. However, a standardized model based on these factors for predicting CR-POPF remains elusive. We aimed to identify inflammatory parameter- and drainage fluid culture-related risk factors for CR-POPF on POD 3 after pancreatoduodenectomy (PD) and distal pancreatectomy (DP). METHODS: Data from 351 patients who underwent PD or DP between 2013 and 2022 at a single institution were retrospectively analyzed. Risk factors for CR-POPF were investigated using multivariate analyses, and a prediction model combining the risk factors for CR-POPF was developed. RESULTS: Of the 351 patients, 254 and 97 underwent PD and DP, respectively. Multivariate analyses revealed that drainage fluid amylase level ≥722 IU/L, culture positivity, as well as neutrophil count ≥5473/mm3 on POD 3 were independent risk factors for CR-POPF in PD group. Similarly, drainage fluid, amylase level ≥500 IU/L, and culture positivity on POD 3 as well as pancreatic thickness ≥11.1 mm were independent risk factors in the DP group. The model for predicting CR-POPF achieved the maximum overall accuracy rate when the number of risk factors was ≥2 in both the PD and DP groups. CONCLUSIONS: Inflammatory parameters on POD 3 significantly influence the risk of CR-POPF onset after pancreatectomy. The combined models based on these values can accurately predict the risk of CR-POPF after pancreatectomy.

Predictive role of the prognostic nutritional index in patients with pancreatic ductal adenocarcinoma who underwent neoadjuvant chemoradiotherapy followed by curative pancreatic resection: A retrospective study using prospectively collected data.

BACKGROUND: Despite a strong association between nutritional indices and disease prognosis, evidence regarding the evaluation of nutritional indices after preoperative treatment for pancreatic ductal adenocarcinoma (PDAC) is insufficient. We evaluated the clinical significance of the prognostic nutritional index (PNI) in patients with resectable (R-) and borderline resectable (BR-) PDAC who received neoadjuvant chemoradiotherapy (NACRT) followed by pancreatic resection. METHODS: We assessed 153 patients with R- and BR-PDAC who underwent NACRT followed by curative resection between 2009 and 2022. We evaluated the association between preoperative PNI after NACRT and short- and long-term outcomes. RESULTS: The median preoperative PNI value after NACRT was 42.1, and the optimal cutoff value from the time-dependent receiver operating characteristic curve was 38.6. The low PNI group (PNI < 38.6, n = 44) exhibited significantly worse inflammatory parameters, surgical outcomes, and prognoses than the high PNI group (PNI ≥ 38.6, n = 109). Multivariate analysis identified preoperative PNI ≤ 38.6 (hazard ratio [HR]: 2.32, 95% confidence interval [CI]: 1.00-5.38, p = .049), blood loss ≥1642 mL (HR: 3.05, 95% CI: 1.65-5.64, p < .001), node positive pathology (HR: 2.10, 95% CI: 1.32-3.34, p = .002), and lack of postoperative adjuvant chemotherapy (HR: 3.55, 95% CI: 2.05-6.15, p < .001) as significant predictors of overall survival. CONCLUSIONS: For patients with R- and BR-PDAC receiving preoperative treatment, it is imperative to closely monitor their nutritional status when determining the optimal surgical procedure timing.

Tumor location, clinicopathological features, and perioperative and prognostic outcomes in patients who underwent pancreatic resection following neoadjuvant chemoradiotherapy for resectable pancreatic cancer: A retrospective study.

BACKGROUND: /Objective: Preoperative treatment of resectable pancreatic ductal adenocarcinoma (PDAC) is gaining popularity worldwide. However, the characteristics of tumors located in the pancreatic head (Ph), or those in the body or tail (Pbt), after surgery following neoadjuvant chemoradiotherapy (NACRT) remain unclear. This study aimed to evaluate and compare the clinicopathological features, perioperative outcomes, and prognosis of patients with resectable PDAC who underwent NACRT followed by curative pancreatic resection, focusing on distinguishing between Ph and Pbt PDACs. METHODS: We included 107 patients with resectable PDAC who underwent curative resection following NACRT between 2009 and 2023. Clinicopathological features, perioperative and prognostic outcomes, recurrence patterns, and prognoses were compared between Ph and Pbt PDAC groups. RESULTS: Tumors were found in the Ph and Pbt in 64 and 43 patients, respectively. Albumin levels and lymphocyte-to-monocyte ratios after NACRT were significantly lower in the Ph group than in the Pbt group. The Pbt group showed significantly higher rates of positive peritoneal lavage cytology and serosal, arterial, and portal vein invasion than the Ph group did. Overall and recurrence-free survival were similar between the two groups. The most common site of initial postoperative recurrence was the lung only in both groups; however, the rate of peritoneal dissemination only was significantly higher in the Pbt group than in the Ph group. CONCLUSIONS: The prognoses based on tumor locations in the Ph and Pbt after surgery following NACRT are similar. Following the resection of resectable Pbt PDAC, the possibility of peritoneal dissemination recurrence should be considered.

Serum Carbohydrate Antigen 19-9 and Metabolite Hypotaurine Are Predictive Markers for Early Recurrence of Pancreatic Ductal Adenocarcinoma.

OBJECTIVE: A significant number of patients experience early recurrence after surgical resection for pancreatic ductal adenocarcinoma (PDAC), negating the benefit of surgery. The present study conducted clinicopathologic and metabolomic analyses to explore the factors associated with the early recurrence of PDAC. MATERIALS AND METHODS: Patients who underwent pancreatectomy for PDAC at Kagawa University Hospital between 2011 and 2020 were enrolled. Tissue samples of PDAC and nonneoplastic pancreas were collected and frozen immediately after resection. Charged metabolites were quantified by capillary electrophoresis-mass spectrometry. Patients who relapsed within 1 year were defined as the early recurrence group. RESULTS: Frozen tumor tissue and nonneoplastic pancreas were collected from 79 patients. The clinicopathologic analysis identified 11 predictive factors, including preoperative carbohydrate antigen 19-9 levels. The metabolomic analysis revealed that only hypotaurine was a significant risk factor for early recurrence. A multivariate analysis, including clinical and metabolic factors, showed that carbohydrate antigen 19-9 and hypotaurine were independent risk factors for early recurrence ( P = 0.045 and P = 0.049, respectively). The recurrence-free survival rate 1 year after surgery with both risk factors was only 25%. CONCLUSIONS: Our results suggested that tumor hypotaurine is a potential metabolite associated with early recurrence. Carbohydrate antigen 19-9 and hypotaurine showed a vital utility for predicting early recurrence.

Tumor-to-blood pool ratio of 18F-fluorodeoxyglucose-positron emission tomography's standardized uptake value as a useful parameter indicating malignant transformation in pancreatic branch-duct intraductal papillary mucinous neoplasm compared to the international Fukuoka guidelines: a retrospective cohort study from surgical resections.

BACKGROUND: Identifying malignant transformation in pancreatic branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) remains challenging, but the standardized uptake value (SUV) obtained from 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT has the potential to become a valuable parameter for differentiation. This study aimed to assess the effectiveness of SUV of FDG-PET/CT in distinguishing low-grade dysplasia (LGD), high-grade dysplasia (HGD), and intraductal papillary mucinous carcinoma (IPMC) within BD-IPMNs. METHODS: We assessed 58 patients with confirmed BD-IPMN undergoing surgery between 2008 and 2022. Receiver operating characteristic curves were plotted using the tumor-to-blood pool ratio (TBR) of FDG-PET/CT in two scenarios: one considering HGD + IPMC as positive and the other considering only IPMC as positive. RESULTS: In the cohort of 58 cases, there were 39 females, and the median age was 71 years. The median TBR value was 1.45 (range, 0.35-25.44). The TBRs exhibited a significant correlation with each histopathology (p < 0.001). Furthermore, in the multivariate analysis, TBR was independently significant in both scenarios, with HGD + IPMC defined as malignant (p = 0.001) and with only IPMC defined as malignant (p = 0.024). CONCLUSIONS: TBR might have the potential to serve as a valuable parameter for indicating malignant transformation in pancreatic BD-IPMNs.

A Novel Fluorescence-Based Leak Test Method for Rectal Anastomoses Using Aerosolized Indocyanine Green.

BACKGROUND: The intraoperative air leak test is commonly performed during rectal surgery to evaluate anastomotic integrity. However, its drawbacks include occasional difficulties in visualizing the exact point of the leak while maintaining the pelvis under saline, the need for repeat testing to identify the leak point, and a lack of continuous visualization of the leak point. OBJECTIVE: To evaluate the feasibility and clinical applicability of using aerosolized indocyanine green, a fluorescent tracer, for detecting rectal anastomotic leakage. DESIGN: Animal preclinical study. SETTING: Animal laboratory at Kagawa University. PATIENTS: Six healthy adult female beagles were included. INTERVENTIONS: An anastomotic leakage model with a single air leak point was created in each dog. Indocyanine green was aerosolized using a nebulizer kit with a stream of carbon dioxide flowing at 1.5 to 2.0 L/min. The aerosol was administered into the rectum transanally, and laparoscopic observations were performed. MAIN OUTCOME MEASURES: Air leak points were observed using a near-infrared fluorescence laparoscope, after which the presence of corresponding indocyanine green fluorescence was verified. RESULTS: Aerosolized indocyanine green was visualized laparoscopically at all anastomosis sites but not elsewhere. The median time from the administration of the aerosol to its visualization was 4.5 seconds. Pathological examinations were performed 4 weeks postsurgery in all dogs, and no histological abnormalities related to aerosolized indocyanine green administration were observed at the anastomosis sites. LIMITATIONS: The leak points were surgically created and did not occur naturally. CONCLUSIONS: Visualization of air leaks at the sites of rectal anastomosis was laparoscopically achievable by administering aerosolized indocyanine green transanally into the rectum in our canine model. This novel fluorescent leak test could be a valid alternative to established methods.

Internal hernia after laparoscopic sigmoidectomy with splenic flexural mobilization and high ligation of the inferior mesenteric vein: A case report.

Several studies have recently reported the rare occurrence of internal herniation of the small bowel after laparoscopic colorectal surgery. Most cases of internal herniation after laparoscopic colorectal surgery occur due to a mesenteric defect. However, there have been no reports on the indications for closing mesenteric defects to prevent the development of an internal hernia. This study reports a case of an internal hernia of the proximal jejunum near the ligament of Treitz in a patient who underwent laparoscopic sigmoidectomy with splenic flexural mobilization and high ligation of the inferior mesenteric vein. Assessing the risk for internal herniation before completing the initial surgery is crucial. Additionally, mesenteric defect closure should be performed to prevent the development of internal hernias among patients with a potential risk.

Recent Advances and Current Management for Desmoid Tumor Associated with Familial Adenomatous Polyposis.

For nearly half a century, desmoid tumor (DT) has been considered a major complication that occurs in approximately 10%-25% of familial adenomatous polyposis (FAP) patients. It is also the leading cause of death in patients undergoing colectomy. We believe that the mortality rate is improving due to the understanding of the natural history of DT and recent advances in medical treatment. The risk factors of DT development include trauma, having a distal germline APC variant, having a family history of DTs, and estrogens. In the era of minimally invasive surgery, several reports demonstrated no significant difference in both surgical approach (laparoscopic vs. open) and surgical procedure (ileal pouch-anal anastomosis vs. ileorectal anastomosis). Regarding the treatment of FAP-associated DT, rapidly proliferating and life-threatening intra-abdominal DT accounts for approximately 10% of FAP-associated DT; however, it has been shown that it can be controlled by identifying and introducing cytotoxic chemotherapy. Moreover, tyrosine kinase inhibitors and γ-secretases, which are used to treat sporadic DT, which is more frequent than FAP-associated DT, are expected to be effective. In the future, such treatment is expected to further reduce the mortality rate from DT associated with FAP. In addition to the conventional staging of intra-abdominal DT, the classification proposed in Japan was recently thought to be useful for the treatment strategy of FAP-associated DTs. In this review, we summarize the recent advances and current management for the FAP-associated DT, including recent data from Japan.

Efficacy of neoadjuvant chemoradiotherapy followed by pancreatic resection for older patients with resectable and borderline resectable pancreatic ductal adenocarcinoma.

BACKGROUND: The benefit of preoperative treatment followed by pancreatic resection in older patients with pancreatic ductal adenocarcinoma (PDAC) remains unclear. In this retrospective analysis of prospectively collected data, we evaluated the significance and safety of preoperative treatment followed by curative resection for older PDAC patients. METHODS: We evaluated 122 patients with resectable and borderline resectable PDAC who received neoadjuvant chemoradiotherapy (NACRT) followed by curative resection between 2009 and 2019. Changes in the prognostic nutritional indices during NACRT, surgical outcomes, and prognosis were compared between older (≥75 years, n = 44) and younger patients (<75 years, n = 78). RESULTS: The completion rate, adverse event rate, changes in prognostic nutritional indices during NACRT, and prognosis were similar between the groups. In multivariate analysis, an elevated C-reactive protein/albumin ratio (CRP/Alb) ≥ 33.1% during NACRT (p = 0.035) and no postoperative adjuvant chemotherapy (p = 0.041) were identified as significant predictors of overall survival. CONCLUSIONS: NACRT followed by pancreatic resection could be safely performed in older patients, with a similar prognosis as that of younger patients, despite an increased frequency of postoperative complications. Elevated CRP/Alb during NACRT and no postoperative adjuvant chemotherapy were poor prognostic factors for older patients.

Indocyanine green fluorescence imaging during laparoscopic rectal cancer surgery could reduce the incidence of anastomotic leakage: a single institutional retrospective cohort study.

BACKGROUND: There is insufficient evidence on whether indocyanine green (ICG) fluorescence angiography can reduce the incidence of anastomotic leakage (AL). This retrospective cohort study aimed to evaluate the effect of ICG fluorescence angiography on AL rates in laparoscopic rectal cancer surgery at a single institution. METHODS: Patients who underwent laparoscopic low anterior resection or intersphincteric resection with ICG fluorescence angiography (ICG group; n = 73) and patients who underwent a similar surgical procedure for rectal cancer without ICG fluorescence (non-ICG group; n = 114) were enrolled consecutively in this study. ICG fluorescence angiography was performed prior to transection of the proximal colon, and anastomosis was performed with sufficient perfusion using ICG fluorescence imaging. AL incidence was compared between both groups, and the risk factors for AL were analyzed. RESULTS: AL occurred in 3 (4.1%) and 14 (12.3%) patients in the ICG and non-ICG groups, respectively. In the ICG group, the median perfusion time from ICG injection was 34 s, and 5 patients (6.8%) required revision of the proximal transection line. None of the patients requiring revision of the proximal transection line developed AL. In univariate analysis, longer operating time (odds ratio: 2.758; 95% confidence interval: 1.023-7.624) and no implementation of ICG fluorescence angiography (odds ratio: 3.266; 95% confidence interval: 1.038-11.793) were significant factors associated with AL incidence, although the creation of a diverting stoma or insertion of a transanal tube was insignificant. CONCLUSION: ICG fluorescence angiography was associated with a significant reduction in AL during laparoscopic rectal cancer surgery. Changes in the surgical plan due to ICG fluorescence visibility may help improve the short-term outcomes of patients with rectal cancer.

Clinical impact of laparoscopic surgery and adhesion prevention material for prevention of small bowel obstruction.

Aim: Adhesive small bowel obstructions (SBO) are one of the most common complications following abdominal surgery, and they decrease patient quality of life. Since 2000, laparoscopic surgery has been employed with increasing frequency, as has adhesion prevention material (APM). In this study we tried to evaluate whether laparoscopic surgery and APM reduce the incidence of SBO. Methods: In Cohort 1, we included patients who developed SBO and received inpatient treatment between 2015 and 2018. We evaluated the elapsed time between precedent surgery and the onset of SBO, and what kind of surgery most often causes SBO. In Cohort 2, we included patients who underwent digestive surgery between 2012 and 2014 and evaluated SBO incidence within 5 y after the precedent surgery. Results: In all, 2058 patients were included in Cohort 1. Of these, 164 had experienced no precedent surgery. Among patients with a history of abdominal surgery, 29.7% experienced SBO within 1 y after the precedent surgery and 48.1% within 3 y. Altogether, 18798 patients were analyzed in Cohort 2. The incidence of SBO after laparoscopic colorectal surgery was lower than that of open colorectal surgery (P < .001), and laparoscopic gastroduodenal surgery was also lower (P = .02). However, there were no differences between laparoscopic and open surgery for other types of surgery. The use of APM had no effect on SBO incidence in any type of abdominal surgery. Conclusions: Laparoscopic surgery helps to reduce SBO incidence only in colorectal surgery, and possibly in gastroduodenal surgery. APM does not reduce SBO after abdominal surgery.

Constrictive pericarditis caused by pericardial metastasis from esophageal squamous cell carcinoma: a case report.

Constrictive pericarditis is a rare condition characterized by clinical signs of right heart failure subsequent to the loss of pericardial compliance. We report a case of constrictive pericarditis due to pericardial metastasis in a patient with a history of esophageal squamous cell carcinoma that had a pathological complete response (pCR) to preoperative chemoradiotherapy. A 66-year-old woman was referred to our division for the treatment of advanced esophageal cancer. Video-assisted thoracoscopic surgery esophagectomy (VATSE) with 3-field lymphadenectomy was performed after neoadjuvant chemoradiotherapy (NAC-CRT). Pathological examination revealed no residual tumor, lymph node metastasis, lymphatic invasion, or vessel invasion. The histological treatment effect of the chemoradiotherapy was pathological complete response (pCR). Five months after surgery, the patient was admitted to a nearby hospital for the treatment of acute pericarditis. However, a month after admission, acute pericarditis progressed to constrictive pericarditis, and she was referred to our hospital for further management. Subsequently, urgent pericardiectomy was performed through a lower half sternotomy incision. After surgery, heart failure improved for a while but worsened again. The patient died 7 days after the surgery. Pathological examination of the resected pericardium revealed evidence of metastasis from squamous cell carcinoma of the esophagus. An autopsy revealed the spread of esophageal cancer to the bilateral pleura, right lung, pericardium, diaphragm, soft tissue surrounding the tracheal bifurcation, and bilateral hilar lymph nodes. Similarly, tumor cells were found in the lymphatic vessels of the pericardium and pleura. Even if pCR is achieved with NAC-CRT, as in our case, esophageal cancer may metastasize and present as constrictive pericarditis within a short period; therefore, careful patient follow-up is essential.

Tumor metabolic alterations after neoadjuvant chemoradiotherapy predict postoperative recurrence in patients with pancreatic cancer.

OBJECTIVE: We investigated the metabolic changes in pancreatic ductal adenocarcinoma to identify the mechanisms of treatment response of neoadjuvant chemoradiation therapy. METHODS: Frozen tumor and non-neoplastic pancreas tissues were prospectively obtained from 88 patients with pancreatic ductal adenocarcinoma who underwent curative-intent surgery. Sixty-two patients received neoadjuvant chemoradiation therapy and 26 patients did not receive neoadjuvant therapy (control group). Comprehensive analysis of metabolites in tumor and non-neoplastic pancreatic tissue was performed by capillary electrophoresis-mass spectrometry. RESULTS: Capillary electrophoresis-mass spectrometry detected 90 metabolites for analysis among more than 500 ionic metabolites quantified. There were significant differences in 27 tumor metabolites between the neoadjuvant chemoradiation therapy and control groups. There were significant differences in eight metabolites [1-MethylnNicotinamide, Carnitine, Glucose, Glutathione (red), N-acetylglucosamine 6-phosphate, N-acetylglucosamine 1-phosphate, UMP, Phosphocholine] between good responder and poor responder for neoadjuvant chemoradiation therapy. Among these metabolites, phosphocholine, Carnitine and Glutathione were associated with recurrence-free survival only in the neoadjuvant chemoradiation therapy group. Microarray confirmed marked gene suppression of choline transporters [CTL1-4 (SLC44A1-44A4)] in pancreatic ductal adenocarcinoma tissue of neoadjuvant chemoradiation therapy group. CONCLUSION: The present study identifies several important metabolic consequences and potential neoadjuvant chemoradiation therapy targets in pancreatic ductal adenocarcinoma. Choline metabolism is one of the key pathways involved in recurrence of the patients with pancreatic ductal adenocarcinoma who received neoadjuvant chemoradiation therapy.

Outcomes of Patients with Left-Sided Obstructive Colorectal Cancer: Comparison between Self-Expandable Metallic Stent and Other Treatment Methods.

INTRODUCTION: This multi-institutional retrospective study aimed to evaluate the efficacy of preoperative self-expandable metallic stent (SEMS) placement for patients with left-sided obstructive colorectal cancer (OCRC). METHODS: Overall, 520 consecutive patients who received treatment for OCRC were enrolled. Of these, the data of 253 patients who underwent primary tumour resection for left-sided OCRC were reviewed. The short- and long-term outcomes were compared between the SEMS group and other three groups: transanal decompression tube (TaDT), decompressing stoma (DS), and emergency resection (ER). RESULTS: The SEMS group had a higher frequency of laparoscopic surgery (p < 0.001), lesser frequency of postoperative stoma (p < 0.001), and more dissected lymph nodes (p < 0.001) than the other groups. Moreover, the SEMS group had shorter postoperative hospital stays than the TaDT, DS, and ER groups (p = 0.005, p = 0.037, and p < 0.001, respectively). The Kaplan-Meier survival curves of recurrence-free survival and overall survival did not differ significantly between the SEMS group and the other three groups in patients with stage II and III diseases. DISCUSSION/CONCLUSION: Elective surgery after SEMS placement may improve short-term outcomes compared to other treatment strategies, with similar long-term outcomes.

Surgical management and outcomes of obstructive colorectal cancer in elderly patients: A multi-institutional retrospective study.

BACKGROUND: The outcomes and prognostic factors of elderly patients with obstructive colorectal cancer are unknown. This was the focus of our multi-institutional retrospective study. METHODS: Medical records of 520 patients (elderly [group E, aged ≥75 years, n = 271]; and nonelderly [group NE, aged <75 years, n = 249]) who received treatment for obstructive colorectal cancer in 2008 to 2018 at 14 leading hospitals in Kagawa prefecture (Japan) were reviewed. Short- and long-term outcomes of patients who underwent tumor resection (n = 438) were compared between the groups. Their prognostic factors were identified. RESULTS: The tumor resection rate was 79% (n = 213) and 90% (n = 225) in groups E and NE, respectively. Group E had more emergency resections (27 [12.7%] vs 15 [6.6%], P = .037), shorter operating times (194 vs 221 min, P < .001), fewer dissected lymph nodes (14 vs 17, P = .004), and less adjuvant chemotherapy (47 [26.8%] vs 122 [76.7%], p < .001) than group NE. Postoperative complication rates and recurrence-free survival were not significantly different between the groups. Overall survival was significantly lower in group E than in group NE. Distant metastases and no postoperative chemotherapy were independent poor prognostic factors for overall survival in groups E and NE. Emergency resection (hazard ratio:1.83; 95% confidence interval: 1.02-3.26) was a significant poor prognostic indicator in group E only. CONCLUSIONS: The short-term outcomes and recurrence-free survival of elderly and nonelderly patients with obstructive colorectal cancer were similar, although the 90-day mortality rate of the elderly patients was higher. Furthermore, elective surgery after bowel decompression is associated with a better outcome in the elderly.

Low prevalence of biliary tract cancer with defective mismatch repair genes in a Japanese hospital-based population.

Recent studies have reported that immune checkpoint inhibitors are effective against various defective mismatch repair (dMMR)/microsatellite instability-high (MSI-H) cancers. A limited number of reports are available on the frequency of dMMR/MSI-H carcinoma in biliary tract cancer (BTC), describing its clinicopathological characteristics and prognosis. The latter carcinoma is also associated with Lynch syndrome (LS). The present study was performed to investigate the frequency of patients with dMMR/MSI-H in BTC and the clinical characteristics of BTC with dMMR/MSI-H in a single institution in Japan. A total of 116 patients with BTC who underwent curative surgical resection at Kagawa University Hospital between January 2008 and December 2017 were included. The protein expression levels of the mismatch repair (MMR) genes [mutL homolog 1 (MLH1), mismatch repair endonuclease PMS2 (PMS2), MutS homolog (MSH)2 and MSH6] were assessed by immunohistochemistry (IHC) using formalin-fixed paraffin-embedded tissue specimens. Subsequently, MSI testing was performed on patients who exhibited loss of MMR protein expression. Loss of expression of one or more proteins was detected in five cases (4.3%). Loss of MLH1/PMS2 expression was observed in one case of intrahepatic cholangiocarcinoma, whereas loss of PMS2 expression was noted in one case of perihilar cholangiocarcinoma. Loss of MSH2/MSH6 and MSH6 expression was noted in two cases of distal cholangiocarcinoma and loss of PMS2 expression in one case of ampullary carcinoma. Out of the five patients, two demonstrated MSI-H. Microsatellite stability was observed in two cases and for one case, no data were available. Two MSI-H cases were patients with loss of expression of MLH1/PMS2 and MSH2/MSH6. None of the five patients exhibited a past medical history or family history of suspected LS. The frequency of dMMR in BTC was ~5%, which was similar to that reported by similar studies performed in other countries. In the present study, IHC appeared to be more useful than MSI testing for detecting MMR abnormalities with regards to the detection rate. Furthermore, there may only be a limited number of patients with BTCs who are likely to benefit from the therapeutic effects of treatment with immune checkpoint inhibitors.