Monitoring ctDNA RAS Mutational Status in Metastatic Colorectal Cancer: A Trial Protocol of RAS-trace and RAS-trace-2 Studies.

Background: Spatial and temporal heterogeneities of RAS and other molecular genes should be considered in the treatment of metastatic colorectal cancer (mCRC) treated with anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (mAbs); acquired RAS mutation is sometimes observed at disease progression of treatment with the anti-EGFR mAb. At the same time, discrepancy of RAS status from tissues and circulating tumor DNA (ctDNA) in the same patient is sometimes observed. Based on this, we commenced two observational studies to clarify these heterogeneities of RAS and BRAF in mCRC, using next generation sequencing from liquid biopsy. Methods/Design: RAS-trace study is an observational study to monitor ctDNA RAS/BRAF/PIK3CA status every 4-12 weeks using the Plasma-SeqSensei™ CRC RUO Kit (Sysmex Inostics GmbH) in mCRC with RAS/BRAF wild-type (wt) on tumor tissue. The primary endpoint was the time to the acquired RAS mutations. A total of 42 patients has been accrued. RAS-trace-2 study is also an observational study aimed at comparing the efficacy of the anti-EGFR mAb in ctDNA RAS/BRAF wt with ctDNA RAS or BRAF mutant mCRC patients, whose RAS/BRAF are wt in tumor tissue. The primary endpoint was progression-free survival in patients with ctDNA RAS/BRAF wt and RAS or BRAF mutant. A total of 240 patients will be accrued over 2 years. Discussion: These trials will help us understanding the clinical significance of spatial and temporal heterogeneities of RAS, BRAF and other genes, while optimizing the anti-EGFR mAb treatment strategies in mCRC.

Two Surgical Cases of Colorectal Cancer in Patients With Immunoglobulin G4-Related Disease.

Immunoglobulin G4-related disease (IgG4RD) is a relatively new disease concept that is most common in Asia. It is a systemic chronic lymphoproliferative disease that is diagnosed by mass formation or thickened lesion, a high serum IgG4 level (≥135 mg/dL), and confirmation of lymphocytes and plasma cells by histopathological examination. The precise mechanism of this disease remains elusive; however, distinguishing IgG4RD from malignancy proves challenging due to its manifestation of swollen lymph nodes and retroperitoneal thickening and fibrosis. Malignancy is also 3.5 times more likely in cases with IgG4RD. In this study, we report two cases of colorectal cancer in patients with IgG4RD who underwent surgery. In both cases, excising the tumor from the retroperitoneal posed a challenge, and swollen lymph nodes were observed without evidence of cancer metastasis. We believe that these are very informative cases, and we report the cases with a literature review of IgG4RD.

A pilot study on the safety and efficacy of neoadjuvant chemo­adoptive immunotherapy for locally advanced rectal cancer.

The safety and efficacy of combination therapy of immune cell therapy and chemotherapy [chemo-adoptive immunotherapy (CAIT)] for patients with stage IV or recurrent colorectal cancer have been reported. In the present study, the safety and efficacy of neoadjuvant CAIT were investigated for preoperative therapy of locally advanced rectal cancer. The study included patients with cT3/T4 or cN (+) rectal adenocarcinoma scheduled for curative surgery. Six patients who consented to participate in the current study were selected as subjects. Neoadjuvant CAIT involves administration of activated autologous lymphocytes, αß T cells, and mFOLFOX6 every 2 weeks for six courses, followed by surgery 4-6 weeks thereafter. Common Terminology Criteria for Adverse Events grade 3 neutropenia was observed in one patient. Neoadjuvant CAIT and curative surgery were performed on all the patients. The confirmed response rate was 67%. Downstaging was confirmed in five patients (83%). Regarding histological effects, two patients were grade 1a and four were grade 2. Regarding immunological reactions, both CD4+ and CD8+ T cell infiltration rates increased after treatment in three patients on tumor-infiltrating lymphocyte (TIL) analysis. In peripheral blood analysis, the total lymphocyte count was maintained in all patients, and the CD8+ T cell count increased by ≥3 times on the pretreatment count in two patients but may not be associated with changes in TILs. During the median postoperative follow-up duration of 24 months, liver and lung metastases occurred in one patient, but all patients survived. In conclusion, neoadjuvant CAIT (αß T cells + mFOLFOX6) can be safely administered for the treatment of advanced rectal cancer. Verification of the efficacy of comprehensive immune cell therapy, especially the induction of antitumor immunity for the prevention of recurrence, will be maintained. The current study is registered with the Japan Registry of Clinical Trials (jRCT; ID, jRCTc030190248; January 21, 2019).

NTRK2 expression in gastrointestinal stromal tumors with a special emphasis on the clinicopathological and prognostic impacts.

Gastrointestinal stromal tumors (GISTs) are typically characterized by activating mutations of the KIT proto-oncogene receptor tyrosine kinase (KIT) or platelet-derived growth factor receptor alpha (PDGFRA). Recently, the neurotrophic tyrosine receptor kinase (NTRK) fusion was reported in a small subset of wild-type GIST. We examined trk IHC and NTRK gene expressions in GIST. Pan-trk immunohistochemistry (IHC) was positive in 25 (all 16 duodenal and 9 out of 16 small intestinal GISTs) of 139 cases, and all pan-trk positive cases showed diffuse and strong expression of c-kit. Interestingly, all of these cases showed only trkB but not trkA/trkC expression. Cap analysis of gene expression (CAGE) analysis identified increased number of genes whose promoters were activated in pan-trk/trkB positive GISTs. Imbalanced expression of NTRK2, which suggests the presence of NTRK2 fusion, was not observed in any of trkB positive GISTs, despite higher mRNA expression. TrkB expression was found in duodenal GISTs and more than half of small intestinal GISTs, and this subset of cases showed poor prognosis. However, there was not clear difference in clinical outcomes according to the trkB expression status in small intestinal GISTs. These findings may provide a possible hypothesis for trkB overexpression contributing to the tumorigenesis and aggressive clinical outcome in GISTs of duodenal origin.

Prognostic factors in patients with high-risk stage II colon cancer after curative resection: a post hoc analysis of the JFMC46-1201 trial.

PURPOSE: The goal of the current study was to identify prognostic factors for disease-free survival (DFS) and overall survival (OS) in high-risk stage II colon cancer. METHODS: The subjects were patients with histologically confirmed stage II colon cancer undergoing R0 resection who met at least one of the following criteria: T4, perforation/penetration, poorly differentiated adenocarcinoma, mucinous carcinoma, and < 12 examined lymph nodes. Patients self-selected surgery alone or a 6-month oral uracil and tegafur plus leucovorin (UFT/LV) regimen. Serum CEA mRNA at ≥ 24 h after surgery and < 2 weeks after registration was also examined as a potential prognostic factor for stage II colon cancer. This study is registered with UMIN-CTR (protocol ID: UMIN000007783). RESULTS: 1880 were included in the analysis to identify prognostic factors for DFS and OS in patients with high-risk stage II colon cancer. In multivariate analyses, gender, depth of tumor invasion, extent of lymph node dissection, number of examined lymph nodes, and postoperative adjuvant chemotherapy (POAC) emerged as significant independent prognostic factors for DFS. Similarly, multivariate analysis showed that age, gender, depth of tumor invasion, perforation/penetration, extent of lymph node dissection, number of examined lymph nodes, and POAC were significant independent prognostic factors for OS. Univariate analyses showed no significant difference in DFS or OS for CEA mRNA-positive and mRNA-negative cases. CONCLUSION: This study showed that gender, depth of tumor invasion, extent of lymph node dissection, number of examined lymph nodes, and lack of use of POAC were significant independent prognostic factors in stage II colon cancer.

Tyrosine kinase alterations in colorectal cancer with emphasis on the distinct clinicopathological characteristics.

AIMS: Tyrosine kinase (TK) alterations, such as anaplastic lymphoma kinase (ALK) fusion, neurotrophic tyrosine receptor kinase (NTRK) fusion, c-ros oncogene 1 (ROS1) fusion and mesenchymal-epithelial transition factor (MET) exon 14 skipping, have been reported in colorectal cancers (CRC). We have previously reported CRCs with NTRK fusion among our cohort. However, their clinicopathological features have not been fully elucidated. METHODS AND RESULTS: Tissue microarray (TMA)-based immunohistochemistry (IHC) was performed on 951 CRC lesions from 944 patients. IHC was evaluated as positive or negative for ALK and ROS1 and 0 to 3+ for c-MET. For ALK and ROS1 IHC-positive cases, RNA-based imbalanced gene expression assays, Archer FusionPlex assays and reverse transcription-polymerase chain reaction (RT-PCR) followed by Sanger sequencing were performed. For c-MET IHC 3+ cases, RT-PCR followed by Sanger sequencing were performed. ALK IHC was positive in three cases (0.2%) and all showed imbalanced ALK gene expression. The following ALK fusions were confirmed: EML4 (exon 21)::ALK (exon 20), EML4 (exon 6)::ALK (exon 19) and HMBOX1 (exon 6)::ALK (exon 20). Two showed microsatellite instability-high/mismatch repair (MMR)-deficient, and all were located in the right colon. ROS1 IHC was positive in one case; however, imbalanced expression and ROS1 fusion was negative. Forty-two cases (4.4%) showed c-MET IHC3+. MET exon 14 skipping was confirmed in nine cases. All cases were microsatellite stable/MMR-proficient, and eight were located in the left colon and rectum. CONCLUSIONS: CRCs with these TK alterations had distinct clinicopathological features. Together with our previous study, 15 cases (1.6%) harboured targetable TK alterations (three NTRK fusion, three ALK fusion, nine MET exon 14 skipping).

Positive Circumferential Resection Margin in Rectal Cancer Is a Robust Predictor of Poor Long-term Prognosis With Clinicopathological Bias Between Groups Compensated by Propensity-score Matching Analysis.

BACKGROUND/AIM: Circumferential resection margin (CRM) is the most reliable predictor of local and distant recurrence in locally-advanced rectal cancer (LARC). The present study was conducted to compare the long-term outcomes between CRM (+) and (-) groups using propensity-score (PS) matching analysis to compensate for bias between groups. PATIENTS AND METHODS: Of 563 consecutive patients with Stage II/III rectal cancer who were treated surgically with curative-intent at Juntendo University Hospital between Jan 1989 and Mar 2018, 412 patients were enrolled retrospectively in the study. The patients were divided into a CRM (+) group (n=21; 5.1%) and a CRM (-) group (n=391; 94.9%). RESULTS: In the entire cohort, recurrence-free survival (RFS), local recurrence-free survival (LRFS), non-local recurrence-free survival (NLRFS), and cancer-specific survival (CSS) were significantly worse among patients in the CRM (+) group compared with those in the CRM (-) group. Univariate analysis demonstrated patients in the CRM (+) group had significantly larger primary tumors (p=0.02), more frequently had open surgery (p=0.009), had an abdominoperineal resection (APR) procedure (p=0.01) and a T4 primary tumor (p<0.0001). After PS matching analysis, in the propensity-matched cohort, RFS, LRFS, NLRFS and CSS were significantly worse among patients in the CRM (+) group compared with those in the CRM (-) group. CONCLUSION: PS matching analysis demonstrated that RFS, LRFS, NLRFS, and CSS were significantly worse among patients in the CRM (+) group compared with those in the CRM (-) group. The present results indicate that CRM (+) is a robust predictor of long-term outcome of LARC, independent of tumor size.

The methylation level of a single cancer risk marker gene reflects methylation burden in gastric mucosa.

BACKGROUND: Gastric cancer risk can be accurately predicted by measuring the methylation level of a single marker gene in gastric mucosa. However, the mechanism is still uncertain. We hypothesized that the methylation level measured reflects methylation alterations in the entire genome (methylation burden), induced by Helicobacter pylori (H. pylori) infection, and thus cancer risk. METHODS: Gastric mucosa of 15 healthy volunteers without H. pylori infection (G1), 98 people with atrophic gastritis (G2), and 133 patients with gastric cancer (G3) after H. pylori eradication were collected. Methylation burden of an individual was obtained by microarray analysis as an inverse of the correlation coefficient between the methylation levels of 265,552 genomic regions in the person's gastric mucosa and those in an entirely healthy mucosa. RESULTS: The methylation burden significantly increased in the order of G1 (n = 4), G2 (n = 18), and G3 (n = 19) and was well correlated with the methylation level of a single marker gene (r = 0.91 for miR124a-3). The average methylation levels of nine driver genes tended to increase according to the risk levels (P = 0.08 between G2 vs G3) and was also correlated with the methylation level of a single marker gene (r = 0.94). Analysis of more samples (14 G1, 97 G2, and 131 G3 samples) yielded significant increases of the average methylation levels between risk groups. CONCLUSIONS: The methylation level of a single marker gene reflects the methylation burden, which includes driver gene methylation, and thus accurately predicts cancer risk.

[A Case of Cecum Cancer with Lymph Node Metastasis and Invasion in the Superior Mesenteric Vein Treated with Combined SMV Resection and Reconstruction].

The patient was a 77-year-old woman. She visited her family doctor with a complaint of bloody stools, and was pointed out a Type 3 colon cancer in the cecum with a colonoscopy. In addition, an enlarged lymph node(#203)was found on the right side of the superior mesenteric vein(SMV). Laparoscopic surgery was initiated, and when the patient was moved to vascular processing, a firm adhesion of the lymph node(#203)was observed on the right side of the SMV. A small laparotomy was added, and a partial combined resection of the SMV was performed en bloc to complete the ileal resection. Histopathological findings showed T4b(transverse colon)N3M0, pStage Ⅲc, and metastatic lymph node(#203)showed evidence of invasion to the SMV. Adjuvant chemotherapy was administered, but lung metastases appeared 4 months and liver metastasis appeared 29 months after surgery. The patient was transferred to a different hospital for best supportive care(BSC)at 34 months after surgery.

Evaluation of the Safety and Efficacy of Modified Laparoscopic Suture Rectopexy for Rectal Prolapse.

Objectives: There are many surgical options for the treatment of rectal prolapse. To date, the efficacy of mesh-free laparoscopic suture rectopexy remains unclear due to the limited number of reports. This study aimed to evaluate the safety and efficacy of laparoscopic suture rectopexy. Methods: This observational cohort study is a retrospective cross-sectional analysis of a continuously maintained database. All patients underwent laparoscopic suture rectopexy for rectal prolapse between April 2012 and March 2018. The primary outcomes measured were recurrence rates and complications of laparoscopic suture rectopexy. Results: A total of 268 patients (29 male and 239 female) underwent laparoscopic suture rectopexy. Their mean age was 77 (19-95) years, and the mean prolapse length was 6.4 (3.5-20) cm. One patient suffered an intraabdominal abscess. Spondylitis developed in another patient following surgery. The median follow-up period was 45 (12-82) months. A total of 22 patients (8.2%) developed recurrence. The average time to recurrence was 15.6 (1-44) months. Multivariate analysis revealed a significant correlation between recurrence and prolapse length >7.0 cm (OR: 1.26, 95% CI: 1.38-1.42, P < 0.01). Conclusions: Laparoscopic suture rectopexy for complete rectal prolapse is a minimally invasive and safe procedure that may lead to lower recurrence rates.

Risk factors for small-bowel obstruction after colectomy for colorectal cancer: a retrospective study.

PURPOSE: Postoperative adhesions are a concerning complication of abdominal surgery with major implications on quality of life. This study aimed to investigate the risk factors for postoperative small-bowel obstruction (SBO) after colectomy for colorectal cancer. METHODS: We reviewed the clinicopathological variables of 1646 patients who underwent colectomy for colorectal cancer between 2009 and 2018. RESULTS: SBO occurred following primary tumor resection for colorectal cancer in 67 (4.1%) of the 1646 patients. The median observation period was 7.5 (range: 3.0-12.0) years. Multivariate analysis revealed that rectal tumors, anastomotic leakages, previous abdominal surgeries, and longer operating times were all correlated with postoperative SBO, but there were no differences in the incidence of SBO between laparoscopic vs. open surgery. The use of adhesion prevention material had no effect on SBO. Our data showed that the onset of SBO tended to be relatively early, within a year after surgery (89.5%). CONCLUSIONS: Tumor localization in the rectum is associated with several problems, including a wide resection area, prolonged operative duration, and high risk of anastomotic leakage, which may increase the risk of SBO. Laparoscopic surgery and adhesion prevention material did not demonstrate a clear preventive effect against SBO.

Local recurrence of submucosal invasive colorectal cancer after endoscopic submucosal dissection revealed by copy number variation.

We report a case in which analysis of copy number variation revealed local recurrence of submucosal invasive colorectal cancer after curative endoscopic submucosal dissection (ESD). An 86-year-old man with a history of abdominoperineal resection of the rectum for rectal cancer underwent resection with ESD for early-stage sigmoid cancer 5 cm away from the stoma opening. At the same time, ileocecal resection was performed for advanced cecal cancer. Twelve months after ESD, advanced cancer occurred in the area of the ESD lesion. It was unclear if the cancer was a local recurrence after ESD, implantation of cecal cancer, or a new lesion. Copy number variation analysis performed for the three lesions revealed that the new lesion originated from residual tumor cells from ESD and was unlikely to be cecal cancer.

Examination of colorectal cancer cases with metal allergy.

PURPOSE: To report our initiatives and treatment results for patients with colorectal cancer with metal allergy. METHODS: A total of 27 patients (2.6%) with a history of metal contact dermatitis were identified among 1027 patients who underwent curative resection of colorectal cancer from 2014 to 2020. The results of the patch test, perioperative results, and postoperative colonoscopy findings were also investigated. RESULTS: The patch test for metal allergens and staples was performed in 21 patients (77.8%), and 13 of them (61.9%) tested positive for at least one metal allergen. Ni (38.1%), Co (28.6%), and Pd (19.0%) showed higher positive rates than other metals, and 1 patient (4.8%) tested positive for staples. Stapled anastomosis/suturing was performed as planned in 15 of 27 patients. In 10 patients, the anastomosis method was changed from stapled to hand-sewn according to the no-patch test results (60%), positivity for multiple metals (20%), positivity for staples (10%), and surgeon's judgment (10%). No complications and abnormal colonoscopy findings were found to be associated with stapled anastomosis/suturing. CONCLUSION: The patch test is useful for selecting an optimal anastomosis method for patients with suspected metal allergy.

Benefits and risks of diverting stoma creation during rectal cancer surgery.

Purpose: A consensus has been reached regarding diverting stoma (DS) construction in rectal cancer surgery to avoid reoperation related to anastomotic leakage. However, the incidence of stoma-related complications (SRCs) remains high. In this study, we examined the perioperative outcomes of DS construction in patients who underwent sphincter-preserving surgery for rectal cancer. Methods: We included 400 participants who underwent radical sphincter-preserving surgery for rectal cancer between 2005 and 2017. These participants were divided into the DS (+) and DS (-) groups, and the outcomes, including postoperative complications, were compared. Results: The incidence of ileus was higher in the DS (+) group than in the DS (-) group (P<0.01); however, no patients in the DS (+) group showed grade 3 anastomotic leakage. Furthermore, early SRCs were observed in 33 patients (21.6%) and bowel obstruction-related stoma outlet syndrome occurred in 19 patients (12.4%). There was no significant intergroup difference in the incidence of grade 3b postoperative complications. However, the most common reason for reoperation was different in the 2 groups: anastomotic leakage in 91.7% of patients with grade 3b postoperative complications in the DS (-) group, and SRCs in 85.7% of patients with grade 3b postoperative complications in the DS (+) group. Conclusion: Patients with DS showed higher incidence rates of overall postoperative complications, severe postoperative complications (grade 3), and bowel obstruction, including stoma outlet syndrome, than patients without DS. Therefore, it is important to construct an appropriate DS to avoid SRCs and to be more selective in assigning patients for DS construction.

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.

[A Case Report for Peritoneal Recurrences by Laparoscopic Surgery after Colorectal Cancer Resection].

We report a cases report of colorectal cancer who underwent repeated resection for peritoneal recurrences by laparoscopic surgery. In 2013, a 70-year-old woman diagnosed with an ascending colon cancer underwent laparoscopic right hemicolectomy. The pathological diagnosis was tub2, pT4aN1M0, Stage Ⅲb. Postoperative adjuvant chemotherapy(uracil and tegafur/Leucovorin)was administered. PET-CT performed at 25 months after the surgery because of CEA elevation. It revealed a peritoneal recurrence in the pouch of Douglas. The following peritoneal recurrences were removed by laparoscopic Hartmann's procedure. Chemotherapy(5-fluorouracil/levofolinate/oxaliplatin/bevacizumab)was administered 11 courses and after that chemotherapy(5-fluorouracil/levofolinate/bevacizumab)was administered 6 courses. PET-CT performed 37 months after the second surgery revealed a peritoneal recurrence near the right ovary in the pouch of Douglas. The following peritoneal recurrences was removed. Chemotherapy(tegafur/gimeracil/oteracil/bevacizumab)was administered 11 courses. The long-term survival has been continued for 7 years and 7 months after first operation. It was considered that laparoscopic surgery for peritoneal recurrence in colorectal cancer is contributed to one of the surgical procedures in selected patients.

Enterocolic Lymphocytic Phlebitis Treated Preoperatively with Biologics and Immunosuppressive Agents.

Enterocolic lymphocytic phlebitis is phlebitis of unknown etiology in which lymphocytes affect veins without arteries and shows evidence of systemic vasculitis in the intestinal wall and mesentery, mainly in the small intestine and colon. Although patients present with a variety of gastrointestinal symptoms and findings like those of inflammatory bowel disease or ischemic bowel disease, there are no specific findings for enterocolic lymphocytic phlebitis. As a result, a diagnosis tends to be made after surgery. There are few case reports of enterocolic lymphocytic phlebitis, and the impact of chronic courses and immunosuppressive drugs on enterocolic lymphocytic phlebitis is not well known. A 47-year-old man was treated with infliximab and steroids for unexplained ulceration and narrowing of the ileocecal area, which was suspected to be inflammatory bowel disease with atypical findings. Lymphocytic phlebitis was noted in the surgical specimen, and enterocolic lymphocytic phlebitis was diagnosed. No recurrence of enterocolic lymphocytic phlebitis was observed postoperatively. This disease should also be considered among patients with inflammatory bowel disease-like lesions that do not respond to infliximab or steroids.

CHFR-Promoter-Methylation Status Is Predictive of Response to Irinotecan-based Systemic Chemotherapy in Advanced Colorectal Cancer.

BACKGROUND/AIM: We investigated whether promoter methylation of the checkpoint-with-forkhead-and-ring-finger-domains (CHFR) gene is a predictor of the efficacy of irinotecan-based systemic chemotherapy for advanced colorectal cancer (CRC) patients. MATERIALS AND METHODS: CHFR-promoter methylation was measured by quantitative methylation-specific PCR (qMSP). The histoculture drug response assay (HDRA) was used in vitro to analyze the correlation between CHFR-promoter methylation and the efficacy of the irinotecan-active-metabolite SN38 in colorectal-cancer tissues from 44 CRC patients. CHFR promoter-methylation was also analyzed for its correlation with clinical response to irinotecan-based systemic chemotherapy of 49 CRC patients. RESULTS: CHFR-promoter methylation significantly-positively correlated with inhibition of colon cancer by SN38 in the HDRA (p=0.002). CHFR-promoter methylation also significantly-positively correlated with clinical response to irinotecan-based systemic chemotherapy (p=0.04 for disease control). CHFR-promoter methylation also significantly-positively correlated (p=0.01) with increased progression-free survival for patients treated with irinotecan-containing FLOFIRI in combination with bevacizumab, the most-frequent regimen in the cohort. CONCLUSION: Sensitivity of advanced CRC patients to irinotecan-based systemic chemotherapy can be predicted by the extent of CHFR-promoter methylation.

[Management of a perforated duodenal diverticulum using an endoscopic nasobiliary drainage tube:a case report].

A man in his 70s visited our hospital for abdominal pain. Upon admission, abdominal computed tomography findings suggested a duodenal diverticular perforation. Upper gastrointestinal endoscopy revealed an incarcerated enterolith in the periampullary diverticulum. We achieved conservative management by inserting an endoscopic nasobiliary drainage tube into the duodenal diverticulum to aid drainage. The patient was discharged without serious complications 35 days after admission. We report a case of duodenal diverticular perforation with an incarcerated enterolith managed conservatively using endoscopic therapy.

[A Case Report of a Giant GIST Markedly Responsive to Neoadjuvant Chemotherapy with Imatinib Mesylate].

Male in his 50s complaining of abdominal pain was referred to our hospital. Abdominal CT scan showed a giant tumor which had diameter of approximately 50 mm in lower rectum. A biopsy specimen was positive for CD34 and c-kit. Based on these findings, it was diagnosed as gastrointestinal stromal tumor(GIST). We treated the patient with neoadjuvant therapy using imatinib mesylate(IM)to reduce the tumor size and to avoid the extensive surgery. The patient started to take IM at a daily dose of 400 mg. After 3 months, CT and MRI revealed that the tumor size decreased(40% reduction). We performed the robot assisted intersphincteric resection(ISR). Although it has been 28 months since the surgery, there are no obvious signs of recurrence. A patient diagnosed with giant GIST could avoid an extensive surgery due to neoadjuvant therapy with IM.