Risk of gastric adenoma and adenocarcinoma in patients with familial adenomatous polyposis in Japan: a nationwide multicenter study.

BACKGROUND: Patients with familial adenomatous polyposis (FAP) have an increased risk of developing gastric neoplasms. However, the clinical course of FAP with these gastric lesions has not yet been fully clarified. The present study aimed to clarify the changes in the incidence risk of developing gastric adenoma or gastric cancer during the lifespan of patients with FAP. METHODS: Four hundred forty-three patients with data regarding gastric adenoma and gastric cancer retrospectively registered in a nationwide Japanese multicenter study were enrolled. The cumulative incidences and hazard rates (HRs) of gastric neoplasms were evaluated. RESULTS: The cumulative incidence rates in 50-year-old patients with FAP were 22.8% for gastric adenoma and 7.6% for gastric cancer, respectively. No significant association was found between gastric neoplasms and the colonic phenotype. The peak age for the HR of gastric adenoma was 65 years, with the highest HR (0.043). Regarding the incidence of gastric cancer, the HR increased moderately up to the age of 40 years, but the increase accelerated from the age of 50 years (HR = 0.0067). CONCLUSION: Careful surveillance of the upper gastrointestinal tract in elderly patients with FAP, such as shortening the interval of follow-up according to age, may be helpful for early diagnosis of gastric cancer.

Gastric Emptying is Accelerated in Patients With Gastric Tube Reconstruction Following Laparoscopic Proximal Gastrectomy.

BACKGROUND: Laparoscopic proximal gastrectomy (LPG) is an attractive option for the treatment of early gastric cancer in the upper third of the stomach. No optimal method of reconstruction after LPG has been established because of problems associated with postoperative reflux. Gastric tube reconstruction, a type of esophagogastrostomy, is a simple procedure, but it is associated with a high frequency of reflux esophagitis (RE). We investigated the relationship between RE and gastric emptying, along with nutritional parameters. SUBJECTS AND METHODS: We compared gastric emptying in patients who had undergone curative LPG with gastric tube reconstruction for gastric cancer with that of patients after total gastrectomy (TG), distal gastrectomy (DG) and of healthy volunteers and patients after DG. The LPG group was divided into an RE LPG-RE (+) group and a non-reflux esophagitis (non-RE) an LPG-RE (-) group, and we compared gastric emptying and indices of nutrition, such as body weight and laboratory findings, between those among LPG-RE (+), LPG-RE (-), and TG groups. RESULTS: The time lag between ingestion and peak 13 CO 2 expiration (T lag) in the healthy volunteer group was significantly shorter in the LPG group longer than those in the healthy volunteer LPG group and TG group. The T lag was significantly shorter in the RE LPG-RE (+) group than in the non-RE LPG-RE (-) group. The percentage change in body weight percentage in the non-RE LPG-RE (-) group was significantly larger than that in the RE LPG-RE (+) group at 12 months after surgery. Both the serum albumin and hemoglobin levels in the non-RE LPG-RE (-) tended to be preserved compared with those in the RE LPG-RE (+) group and TG group. CONCLUSIONS: Gastric emptying was accelerated after LPG, and was associated with RE. Our data suggest that RE could be associated with body weight loss after LPG.

Efficacy and safety of regorafenib dose-escalation therapy for Japanese patients with refractory metastatic colorectal cancer (RECC study).

BACKGROUND: Regorafenib significantly improves overall survival in previously treated metastatic colorectal cancer patients. However, various toxicities, such as hand-foot skin reaction (HFSR), fatigue, and liver dysfunction have limited the use of regorafenib. These toxicities appear soon after treatment initiation. The ReDOS study demonstrated the effectiveness of a weekly dose-escalation therapy of regorafenib starting with a lower daily dose; however, its usefulness in Asian subjects is unknown. We conducted a phase II study to evaluate the safety and survival benefit of regorafenib dose-escalation therapy for Japanese patients. METHODS: Patients with sufficient organ function, who had previously received more than two lines of chemotherapy were included. Regorafenib was started at 80 mg/day and escalated to 120 mg/day in Week 2 and 160 mg/day in Week 3, if no severe drug-related toxicities were observed. The primary endpoint was cancer progression-free survival (PFS). Tumor response and progression were assessed radiologically every 8 weeks. This study was registered in the University Hospital Medical Information Network (UMIN#UMIN000028933). RESULTS: 57 patients were enrolled and all started regorafenib at 80 mg/day. 32 patients (56.1%) were subsequently escalated to 120 mg/day and 19 (33.3%) to 160 mg/day. Only 8 patients (14.0%) discontinued treatment because of adverse events. Median PFS was 1.9 months. Median overall survival was 8.9 months, the response rate was 0%, and the disease control rate was 31.6%. The most frequent adverse event greater than grade 3 was hypertension (19.3%), followed by HFSR (14.0%). CONCLUSIONS: Regorafenib dose-escalation therapy is well tolerated with PFS-like regorafenib standard therapy.

Phase 3 trial of sequential versus combination treatment in colorectal cancer: The C-cubed study.

BACKGROUND: An optimal treatment strategy using oxaliplatin and bevacizumab for metastatic colorectal cancer has not been defined. We investigated whether the sequential treatment using fluoropyrimidines with bevacizumab followed by the addition of oxaliplatin at first progression was better than a combination treatment using fluoropyrimidines and oxaliplatin with bevacizumab. METHODS: In the sequential treatment, the escalation from fluoropyrimidines plus bevacizumab to fluoropyrimidines plus oxaliplatin with bevacizumab was recommended in case of progressive disease. Time to failure of strategy was the primary end-point, whereas the secondary end-points were overall survival, progression-free survival, overall response rate and safety. RESULTS: Three hundred patients with previously untreated metastatic colorectal cancer were randomised to receive either the sequential treatment (n = 151) or the combination treatment (n = 149). The sequential treatment was superior to the combination treatment about time to failure of strategy (15.2 months; 95% CI, 12.5-17.2 months vs. 7.8 months: 95% CI, 6.3-9.5 months; P < 0.001). However, the median overall survival was 27.5 (95% CI, 24.4 to 32.7) months in the sequential treatment and 27.0 (95% CI, 22.8 to 36.0) months in the combination treatment (hazard ratio, 0.92; 95% CI, 0.66 to 1.28; P = 0.61). The overall response rate was 33.1% in the sequential treatment arm and 51.7% in the combination treatment. CONCLUSIONS: The findings support the extension of the sequential treatment starting from fluoropyrimidine plus bevacizumab to selected patients who do not need an objective response to the threatening disease.

Recent trends in the morbidity and mortality in patients with familial adenomatous polyposis: a retrospective single institutional study in Japan.

BACKGROUND: This study aimed to assess current trends in morbidity and mortality among patients with familial adenomatous polyposis (FAP). These data can be used for optimal surveillance and management of such patients. METHODS: Data (November 2001 and April 2020) of genetically confirmed patients with FAP (n = 87) and their first-degree relatives with FAP phenotype (n = 20) were extracted from the Saitama Medical Center database. Standardized mortality ratio (SMR) and standardized incidence ratio (SIR) were estimated using indirect method. RESULTS: Overall, 46 men and 61 women were included; the median age at FAP diagnosis was 28.0 years for both. The SMR for all causes of death was 47.7 (95% confidence interval [CI] 19.1-98.2) in women and 26.5 (95% CI 9.73-57.8) in men. The SIR for colorectal cancer (CRC) was 860 (95% CI 518-1340) in women and 357 (95% CI 178-639) in men. The SMR for CRC was 455 (95% CI 93.7-1330) in women and 301 (95% CI 62.0-879) in men. Thirteen patients died during the observation period, and CRC was the leading cause of death (46%). Other causes of death included desmoid tumor (n = 2), small intestinal cancer (n = 2), ovarian cancer (n = 1), duodenal cancer (n = 1), and sepsis (n = 1). CONCLUSIONS: The mortality ratio, estimated using SMR, remained high. CRC was the leading cause of death, whereas almost half of the causes of deaths were extra-colonic tumors. Life-long management of extra-colonic diseases may improve the prognosis in these patients.

[A Case of Curative Resection of a Retroperitoneal Liposarcoma].

A 55-year-old woman had been admitted to a hospital with abdominal bloating. Retroperitoneal liposarcoma was suspected and diagnosed as not resectable. She was then referred to our hospital with dyspnea and difficulties with movement due to the huge mass. An abdominal CT revealed a large mass originating in the left retroperitoneum. The tumor occupied most of the abdominal cavity, resulting in the displacement of her organs. However, there was no evidence of infiltration of the tumor into the aorta and inferior vena cava. Under a provisional diagnosis of retroperitoneal liposarcoma, a surgical resection was undertaken. The resected specimen had a maximum diameter of 48 cm and weighed 14 kg. Histopathological examination revealed a differentiated liposarcoma. The patient remains alive 6 months after the operation, without recurrence.

Multicenter phase II clinical study of the efficiency and safety of capecitabine plus intermittent oxaliplatin with bevacizumab as first-line therapy in patients with metastatic colorectal cancer (VOICE trial).

PURPOSE: The aim of this phase II study was to evaluate the efficacy and safety of combination therapy with five-cycle CAPOX (capecitabine plus oxaliplatin) plus bevacizumab, followed by five-cycle maintenance therapy with capecitabine plus bevacizumab and reintroduction of CAPOX plus bevacizumab for five cycles, with a preplanned intermittent oxaliplatin strategy in metastatic colorectal cancer (mCRC). METHODS: Patients with untreated mCRC were administered CAPOX (130 mg/m2 oxaliplatin on day 1, 2000 mg/m2/day capecitabine on days 1-14, every 21 days) + bevacizumab (7.5 mg/kg) every 3 weeks for five cycles, maintenance treatment without oxaliplatin for five cycles, and CAPOX + bevacizumab reintroduction for five cycles or upon tumor progression. The primary endpoint was progression-free survival (PFS), and the secondary endpoints were the time to treatment failure (TTF), overall survival, response rate (RR), and safety. RESULTS: Forty-seven patients who fulfilled the inclusion criteria were enrolled in the evaluation of efficacy and safety. Median PFS was 14.1 months (95% confidence interval [CI], 8.6-19.5), and median TTF was 12.3 months (95% CI, 10.3-14.3). The objective RRs were 51.1% (24/47) during induction therapy, 58.3% (21/36) during maintenance therapy, and 63.6% (14/22) during reintroduction therapy. The frequency of patients with neutropenia, diarrhea, peripheral sensory neuropathy, venous thromboembolism, or grade ≥ 3 allergic reactions was 2.1%. CONCLUSION: CAPOX plus bevacizumab therapy with a preplanned intermittent oxaliplatin strategy consisting of brief five-cycle induction therapy, five-cycle maintenance therapy with capecitabine plus bevacizumab, and five-cycle reintroduction therapy consisting of CAPOX plus bevacizumab is safe and effective for mCRC patients. TRIAL REGISTRATION: UMIN ID: 000,005,732, date of registration: June 7, 2011.  https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000006695.

The Pre-treatment Lymphocyte-to-Monocyte Ratio Predicts Efficacy in Metastatic Colorectal Cancer Treated With TAS-102 and Bevacizumab.

BACKGROUND/AIM: Our multicenter phase II TAS-CC3 study demonstrated favorable median progression-free survival (PFS) and overall survival (OS) of 32 metastatic colorectal cancer (mCRC) patients treated with TAS-102 + bevacizumab as 3rd-line treatment. PATIENTS AND METHODS: We investigated the predictive and prognostic values of pre-treatment blood inflammation-based scores, including the neutrophil-to-lymphocyte (NLR), platelet-to-lymphocyte (PLR) and lymphocyte-to-monocyte ratio (LMR) on disease-control (DC), PFS and OS by a post-hoc analysis. RESULTS: Receiver operating characteristic curve analyses of the 3 inflammation-based scores versus DC showed the best predictive performance for LMR, followed by NLR and PLR. The high-LMR group had a significantly higher DC rate than the low group (87.5 vs. 43.8%). The high-LMR group showed significantly longer survival than the low group (4.9 vs. 2.3 m for median PFS) (21.0 vs. 6.1 m for median OS). CONCLUSION: The pre-treatment LMR is a valid predictive and prognostic biomarker for mCRC patients undergoing TAS-102 and bevacizumab treatment.

[A Case of Papillary Carcinoma of Thyroid Associated with Familial Adenomatous Polyposis in a Younger Woman].

Familial adenomatous polyposis(FAP)is an autosomal dominantly inherited disorder, and the result of a germ line variant in the adenomatous poplyposis coli(APC)gene. FAP can be associated with various extracolonic lesions including thyroid cancer, which frequently occurs in women. We report the case of a 15-year-old woman diagnosed as FAP with multiple thyroid papillary carcinomas. Her mother had been treated for FAP with colorectal cancer and thyroid cancer in our department. Multiple tumors with a maximum diameter of 17 mm were detected in the right lobe of the thyroid gland during the preoperative examination. Papillary carcinoma was suspected based on fine-needle aspiration cytology. She was diagnosed with FAP because of multiple polyps on colonoscopy. We performed a subtotal thyroidectomy. Pathological findings revealed a cribriform-morular variant of papillary thyroid carcinoma. We report a rare case of papillary carcinoma of thyroid associated with FAP in a younger woman.

[Idea of Treatment Method for Upper and Lower Rectal Cancer Avoiding Irradiation to Internal and External Sphincter].

BACKGROUND: Preoperative chemoradiotherapy(CRT)followed by total mesorectal excision(TME)is used for locally advanced rectal cancer, but it can induce postoperative anorectal function. The primary objective of this study is to confirm the efficacy and safety of preoperative CRT and TME without irradiation to the internal and external sphincter muscles. SUBJECTS AND METHODS: Patients were eligible for this study if they met the following inclusion criteria: histologically proven rectal cancer, clinical T3T4N0-2 disease, and a distance between anal margin of tumor and the rental line is more than 2 cm. Twelve patients who underwent preoperative CRT and TME between 2013 and 2017 were enrolled. The primary endpoint was completion rate of sphincter-preserving surgery. RESULTS: All patients completed preoperative CRT without Grade 3 or higher adverse effect. Sphincter-preserving surgery was performed in all cases. The 5-year disease-free survival rate was 46.7%, and the local recurrence-free survival rate was 75%, and the overall survival rate was 90.9%. CONCLUSION: It is suggested that preoperative CRT and TME without irradiation to the internal and external sphincter muscles is effective and safe therapy for locally advanced rectal cancer.

The updated five-year overall survival and long-term oxaliplatin-related neurotoxicity assessment of the FACOS study.

PURPOSE: We previously reported the first evidence of oncological benefits from a Japanese phase II trial of oxaliplatin-based adjuvant chemotherapy in patients with stage III colon cancer (the FACOS study). We herein report the long-term survival and persistent oxaliplatin-related peripheral sensory neuropathy (PSN) for patients enrolled in this trial. METHODS: Patients were scheduled to receive the mFOLFOX6 or CAPOX regimen in the adjuvant setting. The five-year overall survival (OS) rate and persistent PSN were evaluated. RESULTS: A total of 130 patients (mFOLFOX6, n = 73; CAPOX, n = 57) were eligible. The 5-year OS rate was 91.4%. No significant difference in the OS rate was observed between regimens (mFOLFOX6, 94.4%; CAPOX, 87.4%; P = 0.25). The incidence of PSN during adjuvant treatment was 55.4% in grade 1 (G1), 30.0% in G2, and 4.6% in G3. No patients showed G3 PSN at 12 months, but G1 or G2 residual PSN after 5 years was observed in 21.8% (G1, 20%; G2, 1.8%). CONCLUSIONS: Updated results from the FACOS study support the benefits of oxaliplatin-based adjuvant chemotherapy in terms of the long-term survival among Japanese patients with stage III colon cancer. However, long-term persistent PSN occurs in about 20% of survivors, counterbalancing the favorable OS.

Clinical outcomes of gastric tube reconstruction following laparoscopic proximal gastrectomy for early gastric cancer in the upper third of the stomach: experience with 100 consecutive cases.

BACKGROUND: Gastric tube reconstruction is a form of esophagogastrostomy performed after laparoscopic proximal gastrectomy (LPG). It is a simple and safe technique, but it may cause reflux esophagitis (RE) and impair postsurgical QOL. For several years, we have developed the gastric tube reconstruction and performed it on more than 100 patients. This study aimed to determine whether gastric tube reconstruction can be a feasible choice after LPG in regard to surgical safety and postoperative nutritional status. METHODS: The subjects consisted of 171 patients who underwent LPG (n = 102) or laparoscopic total gastrectomy (LTG) (n = 69). We compared the two groups in terms of surgical outcomes, incidence rate of RE, and nutritional status including postoperative weight loss and hemoglobin levels. RESULTS: There were no significant differences with regard to the surgical duration and blood loss between the two groups. The incidence of RE was not significantly higher with LPG than with LTG (16.7% vs. 10.1%, respectively; P = 0.07). Later than 2 years and 6 months after surgery, the body weight percentage of preoperative body weight in the LPG group was significantly higher than that in the LTG group. Hemoglobin and ferritin levels in the LPG group were significantly higher than those in the LTG group, later than one after surgery. The overall survival rates were similar between the two groups (5-year survival rates: 97.1% vs. 94.2% in the LPG and LTG groups, respectively; P = 0.69). CONCLUSIONS: Gastric tube reconstruction after LPG is simple and had better outcomes than LTG in terms of postoperative nutritional status.

Phase II study of an oxaliplatin-based regimen for relapsed colon cancer patients treated with oxaliplatin-based adjuvant chemotherapy (INSPIRE study).

BACKGROUND: The aim of this study was to evaluate the efficacy and safety of first-line chemotherapy with re-introduction of oxaliplatin (OX) more than 6 months after adjuvant chemotherapy including OX. METHODS: Stage II/III colon cancer patients with neuropathies of grade ≤ 1 who relapsed more than 6 months after adjuvant chemotherapy including OX were considered eligible. Eligible patients were treated with 5-fluorouracil, l-leucovorin and OX plus molecularly targeted agents or capecitabine and OX plus bevacizumab (BV) or S-1 and OX plus BV. The primary endpoint was the progression-free survival (PFS), and the secondary endpoints were the overall survival (OS), response rate (RR) and toxicity. RESULTS: A total of 50 patients were enrolled between September 2013 and May 2019. Twelve patients received 5-fluorouracil, l-leucovorin and OX (FOLFOX) plus BV, 21 patients received capecitabine and OX plus BV, 10 patients received S-1 and OX plus BV and 7 patients received FOLFOX plus cetuximab or panitumumab. The median PFS was 11.5 months (95% confidence interval [CI] 8.3-16.0), the median OS was 45.4 months (95% CI 37.4-NA), and the RR was 56.0% (95% CI 42.3-68.8). Adverse events of grade ≥ 3 that occurred in ≥ 5% of cases were neutropenia in 6 patients (12%), peripheral sensory neuropathy in 5 patients (10%), diarrhea in 4 patients (8%), hypertension in 4 patients (8%), anorexia in 3 patients (6%) and allergic reactions in 3 patients (6%). CONCLUSIONS: First-line chemotherapy with re-introduction of OX more than 6 months after adjuvant chemotherapy including OX can be used safely with expected efficacy for relapsed colon cancer patients.

[Two Cases of Esophageal Neuroendocrine Carcinoma That Were Successfully Controlled by Multi-Modality Therapy].

Esophageal neuroendocrine carcinoma is extremely rare, and its treatment strategy has not been established. We report 2 cases esophageal neuroendocrine carcinoma. Case 1: A 74-year-old man was diagnosed as having esophageal neuroendocrine carcinoma(clinical T3N4M0, Stage Ⅳa). He received 60 Gy of radiation therapy with etoposide(100 mg/m2)plus cisplatin(80 mg/m2). No recurrence has been detected 1 year after treatment. Case 2: A 78-year-old man was diagnosed as esophageal neuroendocrine carcinoma(clinical T3N0M0, Stage Ⅱ). He underwent esophagectomy with 3 field lymph nodes dissection. Adjuvant chemotherapy was administered with irinotecan(60 mg/m2)plus cisplatin(60 mg/m2). After chemotherapy, he survived 1 year without recurrence.

[Three Cases of Conversion Surgery for Unresectable Gastric Cancer with Multiple Liver Metastases].

We herein report 3 cases of advanced gastric cancer with multiple liver metastases who was successfully treated with systemic chemotherapy and underwent conversion surgery with liver resection. There were 2 males and 1 female patients with a range 68 to 74 years of age. Two patients received S-1 plus oxaliplatin therapy and 1 received S-1 plus cisplatin therapy. All patients survived after 5-49 months postoperatively.

[Changes in Renal Function and Feasibility of Adjuvant Chemotherapy for Colorectal Cancer Patients with Diverting Ileostomy after Ileal Pouch-Anal Anastomosis].

We investigated changes in estimated glomerular filtration rate(eGFR)in 11 colorectal cancer patients(6 familial adenomatous polyposis, 5 ulcerative colitis)who underwent restorative proctocolectomy with ileal pouch-anal anastomosis(IPAA) and diverting ileostomy(DI), the tolerability and adverse events of adjuvant chemotherapy(ACT)in 4 cases. After IPAA, eGFR decreased significantly(p=0.02)and did not return to the preoperative level even after stoma closure(p<0.01). mFOLFOX6 was selected as the regimen in 4 candidates, and no significant changes in eGFR after ACT were observed. The relative dose intensity of oxaliplatin was 91.7%, and no gastrointestinal adverse events of Grade 3 or higher were observed. Although in a small number of cases, mFOLFOX6 as ACT after IPAA and DI may be feasible.

[Conversion Surgery following Second-Line Chemotherapy for Unresectable Gastric Cancer].

We retrospectively analyzed clinicopathological and survival data of 8 patients with unresectable gastric cancer who underwent conversion surgery(CS)following second-line chemotherapy from April 2013 to December 2020. There were 7 males and 1 female patients with a median age of 69(64-76)years old. Five patients had 1 unresectable factor, 2 had 2 unresectable factors, and 1 had 3 unresectable factors. All patients achieved R0 resection. The median survival time(MST) of patients with CS following second-line chemotherapy was significantly longer than that without CS(73.4 vs 12.3 months, respectively). The MST of patients with CS following first-line chemotherapy was significantly longer than that without CS (22.9 vs 12.3 months, respectively). This study suggested that CS following first- or second-line chemotherapy may improve survival duration for unresectable gastric cancer.

Combination of TAS-102 and bevacizumab as third-line treatment for metastatic colorectal cancer: TAS-CC3 study.

BACKGROUND: TAS-102 improved the overall survival of metastatic colorectal cancer (CRC) patients with a median progression-free survival (PFS) in the RECOURSE trial. Subsequently, the combination of TAS-102 and bevacizumab was shown to extend the median PFS (C-TASK FORCE study). However, the study included patients who received second- and third-line treatment. Our study exclusively examined patients receiving this combination as a third-line treatment to investigate the clinical impact beyond cytotoxic doublets. METHODS: This investigator-initiated, open-label, single-arm, multi-centered phase II study was conducted in Japan. Eligible CRC patients were refractory or intolerant to fluoropyrimidine, irinotecan, and oxaliplatin in first- and second-line therapy. TAS-102 (35 mg/m2) was given orally twice daily on days 1-5 and 8-12 in a 4-week cycle, and bevacizumab (5 mg/kg) was administered by intravenous infusion every 2 weeks. The primary endpoint was PFS and the secondary endpoints were time-to-treatment failure, response rate, overall survival (OS), and safety. RESULTS: Between June 2016 and August 2017, 32 patients were enrolled. All patients previously received bevacizumab. The median PFS was 4.5 months; the median overall survival was 9.3 months. Partial response was observed in two patients. The most common adverse events above grade 3 were neutropenia followed by thrombocytopenia. There were no non-hematological adverse events above grade 3 and no treatment-related deaths occurred. CONCLUSIONS: This study met its primary endpoint of PFS, which is comparable to the results of the C-TASK FORCE study. The TAS-102 and bevacizumab combination has the potential to be a therapeutic option for third-line treatment of metastatic CRC.

Endocytoscopic observation with methylene blue staining for duodenal neoplasms associated with familial adenomatous polyposis.

Duodenal cancer is a leading cause of death after colectomy in patients with familial adenomatous polyposis (FAP). Detailed endoscopic evaluation of duodenal lesions with potential for carcinoma development is therefore mandatory. Here we investigated the features of duodenal lesions in FAP patients using an endocytoscopy system (ECS). We retrospectively reviewed duodenal lesions in 15 cases of FAP using an ECS (GIF-H290EC) with methylene blue (MB) as the vital dye. With reference to the Spigelman classification, we investigated the number of lesions using white light (WL), narrow-band imaging (NBI), and MB staining. Using the maximum magnification power of the ECS we investigated the histology (duct openings or finger-like projections) and grade of dysplasia (presence or absence of enlarged oval-shaped nuclei) of the lesions. The number of duodenal lesions increased in ascending order of WL, NBI, and MB (P < 0.05). Among 51 MB-unstained lesions, 46 (90.2%) were proven to be duodenal neoplasms histologically. Duct openings were seen in 90.2% of tubular adenomas and tubulovillous adenomas. Finger-like projections were seen in 33.3% of tubular adenomas and in 88.2% of tubulovillous adenomas. Enlarged oval-shaped nuclei were observed in 100% of duodenal cancers, 33.3% of high-grade adenomas, and 9.4% of low-grade adenomas. MB staining allows more accurate detection of duodenal neoplasms in comparison to conventional WL and NBI observation. In cases of FAP, use of the maximum magnification power of the ECS may allow selection of lesions with high malignant potential.

Prevalence and Molecular Characterization of Defective DNA Mismatch Repair in Small-bowel Carcinoma in a Japanese Hospital-based Population.

OBJECTIVES: To investigate the prevalence and molecular characteristics of defective DNA mismatch repair (dMMR) in small-bowel carcinoma (SBC) in a Japanese-hospital population. METHODS: Immunohistochemistry was performed to evaluate the expression of MMR proteins (MLH1, MSH2, MSH6, and PMS2) in formalin-fixed paraffin-embedded sections prepared from surgically resected primary SBCs from 30 patients during March 2002 to March 2017. Genetic testing for Lynch syndrome was performed in patients who demonstrated MMR protein loss. RESULTS: Two of 30 patients (6.7%) demonstrated concomitant loss of MSH2/MSH6 protein expression. Further genetic testing identified a pathogenic MSH2 variant in one of these patients. CONCLUSIONS: The prevalence of dMMR SBCs in a Japanese hospital-based population seems lower than that reported in previous studies. To determine whether dMMR SBCs might be strongly linked to Lynch syndrome, there is a need for further investigation with a larger sample size.