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A 55-year-old woman became aware of a tumor on the left side of the head in July, 2020 and was referred to our hospital in September because of its rapid growth. A head CT showed a neoplastic lesion of the skull. A CT from the neck to the pelvis revealed an ascending colon tumor and multiple lesions in the liver, which was suspected as metastasis. A colonoscopy also showed a type 2 like lesion in the ascending colon, and a biopsy showed adenocarcinoma. A pedunculated polyp had been pointed out in the ascending colon at another hospital four years previously, and the pathological result was an adenoma, but endoscopic mucosal resection was not performed. It is considered that the adenoma became advanced colon cancer with metastasis through the mechanism of multistage carcinogenesis. Metastatic lesions of the ascending colon cancer was suspected with regard to the skull lesion. In addition to the rapid growth, surgical removal was desirable from the viewpoint of cosmetology, and surgery was performed in November. The postoperative pathological diagnosis was a metastatic skull tumor derived from ascending colon cancer. The diagnosis was Stage IVb according to the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma (9

We report a rare case of postoperative ascending colon cancer metastasis to the right external iliac lymph nodes. A 57- year-old woman underwent a laparoscopic right colectomy and D3 lymph node dissection. Pathological findings indicated a Stage Ⅲb, pT4aN1bM0 cancer. Because side effects were observed on adjuvant chemotherapy with FOLFOX, she was switched to S-1 administration every other week. Sixteen months postoperatively, right inguinal pain and elevated CEA values were noted. CT revealed two swollen right external iliac nodes with high FDG uptake on PET-CT. With the diagnosis of lymph node metastasis, an open celiotomy was performed to remove the lymph nodes. Pathological findings confirmed lymph node recurrence of ascending colon cancer. Postoperatively, her CEA values were normal and no recurrence was noted. This rare occurrence highlights the importance of examining adjacent lymph nodes for possible tumor recurrence. We report this case with the necessary literature review.

Pembrolizumab is a novel immune-checkpoint inhibitor used for treatment of microsatellite instability-high (MSI-H) colorectal cancer. Several studies have reported clinical complete response (CR) after treatment with pembrolizumab, but none has confirmed pathological CR. Here we provide the first description of pathological CR with R0 resection after immune-checkpoint therapy. A 45-year-old man presented at our hospital with abdominal distention and highly elevated tumor markers. Contrast-enhanced abdominal CT showed a 110 × 75 mm bulky mass with markedly swollen lymph nodes and an isolated peritoneal metastasis in the pelvic space. Biopsy revealed poorly differentiated adenocarcinoma. We diagnosed ascending colon cancer cT4aN2bM1c Stage IVc. A biopsy specimen obtained during systemic chemotherapy (FOLFOXIRI) was confirmed pathologically as MSI-H, after which the treatment was changed to pembrolizumab. The tumor markers rapidly decreased to within normal ranges after three courses of treatment. After twenty courses, CT revealed shrinkage of the main tumor, lymph node metastases, and the peritoneal metastasis, and we performed extended right hemi-colectomy with dissection of the peritoneal metastasis. No residual tumor cells were found histologically. The patient achieved pathological CR and the postoperative course was uneventful. An accurate diagnosis and appropriate follow up are crucial for obtaining sufficient therapeutic effect of pembrolizumab.

BACKGROUND Sarcomatoid carcinoma is a rare tumor that can occur in different organs and anatomical locations. Colonic sarcomatoid carcinoma, also known as carcinosarcoma, is an extremely rare tumor, with only 32 cases reported world-wide. The pathogenesis and guidelines for treatment are poorly understood due to the rarity and invasiveness of the disease. CASE REPORT A 77-year-old woman presented with worsening lower abdominal pain and associated fever after having initially been diagnosed with stump appendicitis and associated phlegmon 3 weeks prior, which was treated with antibiotics. Repeat imaging revealed an extraluminal versus perforated colonic mass with associated phlegmon. The patient's condition continued to worsen, with development of obstructive-like symptoms, resulting in operative intervention involving a R2 right hemicolectomy, stapled ileo-colostomy, and partial omentectomy. The patient had an uneventful remainder of her hospitalization other than continued lower abdominal pain. After initial discharge, the patient presented to an outside hospital due to continued deterioration of health, with findings of an additional mass, likely secondary to the previous lymphadenopathy. Ultimately, goals of care were discussed, and the decision was made to provide palliative care, and the patient died due to her illness 32 days after the initial procedure. CONCLUSIONS Carcinosarcoma is an extremely rare tumor with scant research guiding treatment guidelines. Current guidelines gathered from previous case reports suggest treating colorectal carcinosarcoma as adenocarcinoma. Additional research and studies are needed to establish appropriate therapeutic guidelines for carcinosarcoma.

Background As right colon polyps are challenging to detect, a retroflexed view of right colon (RV) may be useful. However, cecal retroflexion (CR) without a RV to the hepatic flexure (HF) is inadequate. We aimed to determine the frequency of CR and quality of the RV in routine practice. Methods This prospective observational study performed at an academic medical center assessed colonoscopy inspection technique of endoscopists who had performed ≥ 100 annual screening colonoscopies. We video recorded ≥ 28 screening/surveillance colonoscopies per endoscopist and randomly evaluated 7 videos per endoscopist. Six gastroenterologists blindly reviewed the videos to determine if CR was performed and HF withdrawal time (cecum to HF time, excluding ileal/polypectomy time). Results Reviewers assessed 119 colonoscopies performed by 17 endoscopists. The median HF withdrawal time was 3 min and 46 s. CR was performed in 31% of colonoscopies. CR frequency varied between endoscopists with 9 never performing CR and 2 performing CR in all colonoscopies. When performed, nearly half (43%) of RVs did not extend to the HF with median RV duration of 16 s (IQR 9–30 s). Three polyps were identified in the RV (polyp detection rate of 8.1%), all identified prior to a forward view. Conclusions CR is performed infrequently in routine practice. When CR is performed, the RV is of low quality with a very short inspection duration and insufficient ascending colon examination. Further education is required to educate endoscopists in optimal technique to improve overall colonoscopy quality.

BACKGROUND AND STUDY AIMS Non-pedunculated lesions are easily missed on endoscopy, and histopathological examination shows that some of these lesions are adenomas. Adenoma is a precursor of colorectal cancer, a common tumor of the digestive tract. This study was conducted to compare the detection efficacy of non-pedunculated lesions in the same patient under different modes of blue laser endoscopy and to determine whether the surface pattern of the sample was consistent with its histopathological results. PATIENTS AND METHODS A total of 91 patients with non-pedunculated lesions diagnosed at our hospital between April 2018 and March 2019 were included in this study. White light imaging (WLI), linked color imaging (LCI), and blue laser imaging (BLI) modes were used to record the location, number, and Hiroshima classification of the surface patterns of the non-pedunculated lesions. The lesions were removed by different endoscopic excision methods for histopathological examination; the histopathological results were compared with the surface patterns. RESULTS A total of 105, 198, and 223 lesions were detected using the WLI, BLI, and LCI modes, respectively. The Wilcoxon signed rank test revealed a significant difference in the number of lesions detected using each observation mode (p

Single-port laparoscopic extended right hemicolectomy with complete mesocolic excision and central vascular ligation is technically challenging, and a standardized procedure is needed to minimize technical hazards. As a first step, the hepatic flexure is mobilized from the duodenum, and the third part of the duodenum and pancreatic head was exposed. Next, the ileocecal vessels are divided at the root using a medial-to-lateral approach, and the cecum is separated from the retroperitoneal space. This process completes the mobilization of the right colon. In the second step, the omental bursa is opened, and the inferior border of the pancreas is exposed. The mobilized right colon is turned around to the left of the superior mesenteric vein, continuing to separate the mesentery from right to left side, and the right colic vessels are divided at the roots. The inverted right colon is restored to its original position, and the mesenteric fat is dissected along the left edge of the superior mesenteric artery to the inferior border of the pancreas. A total of 57 consecutive patients with advanced hepatic flexure colon cancer (n = 24) and transverse colon cancer (n = 33) underwent S-ERHC. The conversion rate to open surgery was 5.3%. Operative time, blood loss, and number of harvested lymph nodes were 232 min (interquartile range [IQR], 184–277 min), 5 mL (IQR, 5–66 mL), and 30 (IQR, 22–38), respectively. According to the Clavien–Dindo classification, the grade ≥ 2 complication rate was 10.5%. Median duration of hospitalization was 9 days (IQR, 7–13 days). Single-port laparoscopic extended right hemicolectomy using a right colon rotation technique is safe, feasible, and useful. This technique of repeating the inversion and restoration of the right colon may help avoid bleeding and damage to other organs and facilitate reliable lymph node dissection.

Background The incidence of early‐onset colorectal cancer (EOCRC) is rising. Left‐sided colorectal cancer (LCC) is associated with better survival compared to right‐sided colon cancer (RCC) in metastatic disease. NCCN guidelines recommend the addition of EGFR inhibitors to KRAS/NRAS WT metastatic CRC originating from the left only. Whether laterality impacts survival in locoregional disease and EOCRC is of interest. Methods 65,940 CRC cases from the National VA Cancer Cube Registry (2001–2015) were studied. EOCRC (2096 cases) was defined as CRC diagnosed at, In EOCRC patients, LCC is associated with better OS than RCC only in patients with metastatic disease. In the overall population, LCC is associated with better OS in all stages except stage II, which might be due to the high incidence of MMRd tumors in this subpopulation.

BackgroundAnti-transcriptional intermediary factor 1 gamma (TIF1γ) antibody is a marker for predicting cancer association in patients with dermatomyositis (DM). The overall survival rate in DM patients with cancer was reported to be considerably worse than that in DM patients without cancer. However, the treatment for cancer-associated DM remains controversial, because the treatment priority between surgical resection for the tumor and internal treatments, including glucocorticoids, immunosuppressive agents, and intravenous immune globulin, has not been established.Case presentationWe report the case of a 57-year-old Japanese man diagnosed with anti-TIF1γ antibody-positive DM associated with ascending colon cancer. His clinical symptoms included facial and brachial edema, muscle weakness, dysphagia, myalgia, and rash. Physical examination revealed periorbital edema and Gottron's papules over his knuckles with brachial edema, and tenderness and weakness of the proximal limb muscles. The findings of hyperintense muscles in T2-weighted sequences of brachial contrast-enhanced magnetic resonance imaging and the infiltration of lymphocytic cells and CD4-positive lymphocytes from muscle biopsy were compatible with the diagnostic criteria for dermatomyositis. Anti-TIF1γ antibody was positive by immunoprecipitation assay. He first started internal treatment including intravenous immunoglobulin, steroid pulse, prednisolone, and azathioprine, followed by surgical resection for the tumor because of the elevation of creatine kinase and progression of dysphagia. However, clinical symptoms did not improve, and the patient died 6 months later.ConclusionsWe faced difficulties in determining the treatment priority between surgical resection and internal treatment for our case; therefore, this case would be educational for readers. We searched PubMed to identify English-language case reports of anti-TIF1γ antibody-positive dermatomyositis with malignancy and found 21 reported cases. We herein review and summarize previously reported cases of anti-TIF1γ antibody-positive DM with malignancy. Cancer screening is essential in patients with anti-TIF1γ antibody-positive dermatomyositis because it is associated with a high prevalence of malignancies. Our review revealed that initial surgical treatment should be recommended for better prognosis if the general condition allows.

To define the incidence of gastroepiploic lymph node (GLN) metastasis in patients with cancer of the transverse colon, including the hepatic flexure, and to identify the preoperative predictors of GLN involvement in a large-volume center in China. This retrospective monocentric cross-sectional study respected the STROBE statement. Of 3208 consecutive patients who underwent colon cancer resection, a total of 371 patients with cancer of the transverse colon including the hepatic flexure who underwent complete mesocolic excision and GLN resection in our center were retrospectively reviewed between November 2010 and November 2017. Logistic regression was performed to identify predictors of GLN metastasis. Endoscopic obstruction was defined as a luminal obstruction of the colon severe enough to prevent the colonoscope from passing beyond the tumor regardless of the presenting symptoms. The GLN involvement rate was 4.0 (2.0–6.1)%. Patients who had GLN involvement had a significantly higher rate of endoscopic obstruction (P = 0.030), higher rate of signet ring adenocarcinoma or lymphovascular invasion (P

This study evaluates the prognostic significance of EMVI and DEMI on preoperative CT in patients with ascending colon cancer.This retrospective study included consecutive patients with T3 ascending colon cancer from January 2012 to December 2016 in a tertiary center. Two radiologists independently reviewed EMVI, DEMI, and nodal status on preoperative CT. We assessed the association of age, sex, mucinous adenocarcinoma, EMVI, and DEMI with metastasis on preoperative CT using univariable and multivariable analysis. We also compared disease-free survival (DFS) with and without variables (age, sex, mucinous adenocarcinoma, EMVI, DEMI and adjuvant chemotherapy) using Cox's proportional hazards models. We assessed interobserver agreements on imaging features using the Cohen's weighted kappa.Of 237 patients [107 men; mean (standard deviation) age, 66 (13) years], 24 had metastases on preoperative CT. Positive EMVI was associated with metastasis (odds ratio 16.9; P 0.001) on multivariable analysis. Of 194 patients [83 men; 65 (13) years] included for DFS analysis, recurrence was observed in 31 (16%) with median follow-up of 53 months. Positive EMVI [hazard ratio (HR) 4.8; P 0.001] and DEMI 5 mm (HR 5.5; P 0.001) were associated with worse DFS. Interobserver agreements were good (kappa = 0.64-0.67).Positive EMVI and DEMI 5 mm on preoperative CT were associated with a worse T3 ascending colon cancer prognosis. Thus, these CT findings could be used as imaging biomarkers for T3 ascending colon cancer risk stratification.

A 71-year-old woman who have been taking Sanshishi for 50 years until the age of 70 for dermatitis underwent colonoscopy( CS)to reveal the reason of abdominal pain. CS showed ascending colon tumor(AT)with major axis 3 cm and suspicious of the mesenteric phlebosclerosis. Although endoscopic submucosal dissection(ESD)was performed for AT, colon perforation due to colonic wall fibrosis was occurred and ESD was suspended. Therefore, surgical resection was planned. Intraoperative observations by laparoscopy showed that the color of colon serosa from the cecum to the splenic flexure was grayish white and colonic wall thickening with lead tubular change was observed. From the descending colon to the sigmoid colon, wall thickening was mild, and Haustra was confirmed. Although the tumor location was in the ascending colon, laparoscopic subtotal colectomy and functional end-to-end anastomosis of ileum and sigmoid colon was performed for safe intestinal anastomosis. For treat of colon cancer complicated mesenteric phlebosclerosis(MP), endoscopic resection is considered difficult due to fibrosis and extended resection of the colon may be required to reduce the risk of anastomotic leakage. Herein, we report our case and details of past reported literatures.

Background The effect of ageing on total collagen content of human colon has been poorly investigated. The aim of this study was to determine if ageing altered total collagen content and distribution in the human colon. Methods Macroscopically normal ascending colon was obtained at surgery from cancer patients (n = 31) without diagnosis of diverticular disease or inflammatory bowel disease. Masson’s trichrome and Picrosirius red stains were employed to identify the total collagen content and distribution within the sublayers of the colonic wall for adult (22–60 years; 6 males, 6 females) and elderly (70 – 91years; 6 males, 4 female) patients. A hydroxyproline assay evaluated the total collagen concentration for adult (30–64 years; 9 male, 6 female) and elderly (66–91 years; 8 male, 8 female) patients. Key results Histological studies showed that the percentage mean intensity of total collagen staining in the mucosa, submucosa and muscularis externa was, respectively, 14(1.9) %, 74(3.2) % and 12(1.5) % in the adult ascending colon. Compared with the adults, the total collagen fibres content was increased in the submucosa (mean intensity; 163.1 ± 11.1 vs. 124.5 ± 7.8; P < 0.05) and muscularis externa (42.5 ± 8.0 vs. 20.6 ± 2.8; P < 0.01) of the elderly patients. There was no change in collagen content of the mucosa. The total collagen concentration was increased in the elderly by 16%. Sex-related differences were not found, and data were combined for analysis. Conclusions Greater total collagen content was found in the submucosa and muscularis externa of the elderly human male and female colon. These changes may contribute to a possible loss of function with ageing.

Peritoneal dialysis (PD)-related peritonitis is a common complication of PD. Nonocclusive mesenteric ischemia (NOMI) is a rare complication of PD-related peritonitis, has a high mortality rate, and therefore should be detected early once it occurs. We describe a case of a 70-year-old woman on PD presented with moderate abdominal pain and low blood pressure, which contributed to the early diagnosis of PD-related peritonitis complicated with NOMI. Increased white cell count of 7150/μL (neutrophil, 84%) in dialysate effluent was diagnostic of PD-related peritonitis, which was later found to be caused by Pseudomonas putida. Computed tomography with contrast performed after administering crystalloids revealed hepatic portal venous gas, pneumatosis intestinalis in the ascending colon, and normal enhancement of the bowel wall and mesenteric arteries, which suggested a reperfusion of the previously ischemic ascending colon. Colonoscopy on hospital day seventeen revealed mucosal hemorrhage and ulcers in the entire right colon and the terminal ileum while the remaining colon was normal. These findings are compatible with the consequence of NOMI. Increased peak systolic velocity of the superior mesenteric artery (SMA) implied its stenosis. Past studies show that ischemia of the colon in patients with chronic kidney disease commonly occurs in the right colon. Arteriosclerosis of the SMA due to the long history of chronic kidney disease and diabetes might have caused its vulnerability to low blood pressure. Abdominal complications including NOMI should be screened for when a patient presents with low blood pressure and strong abdominal pain. This is the first case report that shows colonoscopy images of the colonic ulcers post-NOMI and PD-related peritonitis.

We describe the case of an 84-year old female who was taking rivaroxaban 30 mg/day and had a medical history of atrial fibrillation. She underwent endoscopic mucosal resection of a 5-mm adenoma located in the hepatic flexure of the transverse colon. Following the procedure, she developed gradually intensifying abdominal pain, with the appearance of small amount of blood in the feces. For that reason, she visited our facility on the 5th day post-endoscopic mucosal resection. At the time of the visit, contrast-enhanced abdominal computed tomography revealed no extravasation or free air; however, bloody ascites was confirmed in the peritoneal cavity. Thus, the patient was diagnosed with post-endoscopic mucosal resection intra-abdominal hemorrhage and hospitalized the same day. After admission, rivaroxaban was discontinued and patient condition monitored. Because subsequent abdominal computed tomography revealed no distinct increase in bloody ascites, no interventional radiological or surgical procedure was performed, and the patient was discharged after providing only conservative treatment. While hemorrhage and perforation are the main complications after colonic endoscopic mucosal resection, so far, there have been a few reports on the occurrence of intra-abdominal hemorrhage following endoscopic mucosal resection. Emergency treatment is sometimes required in patients with intra-abdominal hemorrhage. It is important to keep in mind that this complication, although very rare, may occur, particularly in patients taking anticoagulants.

Right-sided colonic diverticulitis represents less than 5% of diverticulitis cases in North America. The purpose of this study was to describe the management and outcomes for patients with a first episode of right-sided diverticulitis in a North American center. This was a retrospective cohort study, including all patients managed for right-sided diverticulitis at a single tertiary-care institution from 2000 to 2017. Patient demographics, disease characteristics, and treatment strategies were described. Short- (emergency surgery, operative morbidity, treatment failure) and long-term (recurrence, elective operation) outcomes were reported. Patients with right-sided diverticulitis were then compared to a cohort of patients with left-sided diverticulitis. Sixty-seven patients were managed for a first episode of right-sided diverticulitis, three (4.5%) of which were subsequently diagnosed with right-sided colon cancer; 64 patients therefore formed the population. Mean age was 51.2 ± 17.7 years. Eight patients (12.5%) self-identified as being Asian. The majority of patients had uncomplicated disease (90.6%); six (9.4%) presented with complicated diverticulitis. Most cases were diagnosed by computed tomography (78.1%), while 17.2% were diagnosed intra-operatively and 4.7% by pathology. Almost all patients diagnosed by computed tomography were managed nonoperatively. Fifteen patients (23.4%) were managed surgically: ten for suspected appendicitis, three for suspected colon mass, and two for diffuse peritonitis. After a median follow-up of 74.8 months (IQR 30.2–130.5), only two patients (3.1%) developed recurrent right-sided diverticulitis. Among patients managed nonoperatively, recurrence was significantly lower in patients with right-sided diverticulitis relative to left-sided diverticulitis (4.1% vs. 32.8%, p

BACKGROUND Obesity is a risk factor for colorectal cancer, yet metabolic distinctions between healthy right and left colon tissue, before cancer is diagnosed, remains largely unknown. This study compared right-ascending and left-descending colon tissue metabolomes to identify differences from the stool metabolome in normal weight, overweight, and obese adults. AIM To examine right and left colon tissue metabolites according to body mass index that may serve as mechanistic targets for interventions and biomarkers for colon cancer risk. METHODS Global, non-targeted metabolomics was applied to assess right-ascending and left-descending colon tissue collected from healthy adults undergoing screening colonoscopies to test the hypothesis that BMI differentially impacts colon tissue metabolite profiles. The colon tissue and stool metabolome of healthy adults (n = 24) was analyzed for metabolite signatures and metabolic pathway networks implicated in progression of colorectal cancer. RESULTS Ascending and descending colon contained 504 host, food, and microbiota-derived metabolites from normal weight, overweight and obese adults grouped according to body mass index. Amino acids, lipids, and nucleotides were among the chemical types that further differentiated from the stool metabolite profiles. Normal weight adults had 46 significantly different metabolites between ascending and descending colon tissue locations, whereas there were 37 metabolite differences in overweight and 28 metabolite differences for obese adults (P < 0.05). Obese adults had trimethylamine N-oxide, endocannabinoids and monoacylglycerols with different relative abundances identified between ascending and descending colon. Primary and secondary bile acids, vitamins, and fatty acids also showed marked relative abundance differences in colon tissue from overweight/obese adults. CONCLUSION There were metabolite profile differences between right-ascending and left-descending colon tissue in healthy adults. Colon lipids and other metabolites in obese and overweight adults were distinguished from normal weight participants and associated with gut inflammation, nutrient absorption, and products of microbiota metabolism.

Primary tumor location is an established prognostic factor in patients with (metastatic) colon cancer. Colon tumors can be divided into left‐sided and right‐sided tumors. The aim of this study was to determine the impact of primary tumor location on treatment and overall survival (OS) in patients with peritoneal metastases (PM) from colon cancer. This study is a retrospective, population‐based cohort study. Records of patients diagnosed with colon cancer and synchronous PM, from 1995 through 2016, were retrieved from the Netherlands Cancer Registry (NCR). Data on diagnosis, staging, and treatment were extracted from the medical records by specifically trained NCR personnel. Information on survival status was updated annually using a computerized link with the national civil registry. In total, 7930 patients were included in this study; 4555 (57.4%) had a right‐sided and 3375 (42.6%) had a left‐sided primary tumor. In multivariable analysis right‐sided primary tumor was associated with worse OS (HR: 1.11, 95% CI 1.03‐1.19, P = .007). Of all patients diagnosed with PM, 564 (7.1%) underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS‐HIPEC). Patients with left‐sided primary tumors were more often candidates for CRS‐HIPEC (6.5% vs. 8.0%, P = .008). OS of patients with right‐ and left‐sided tumors who underwent CRS‐HIPEC did not significantly differ. In conclusion, primary right‐sided colon cancer was an independent prognostic factor for decreased OS in patients diagnosed with synchronous PM. In patients treated with CRS‐HIPEC location of the primary tumor did not influence survival., Primary tumor location is an established prognostic factor for patients with colon cancer. Little is known about the impact of tumor location on the outcomes of patients with peritoneal metastases. In a population‐based study in the Netherlands, primary right‐sided colon cancer was an independent prognostic factor for decreased survival in patients with synchronous peritoneal metastases. In patients with synchronous peritoneal metastases treated with CRS‐HIPEC, location of the primary tumor did not influence survival.

A 74-year-old woman underwent right hemicolectomy for ascending colon cancer in March 2013, after which she received adjuvant chemotherapy(UFT plus UZEL)for 6 months. In October 2014, left supraclavicular lymphadenopathy appeared, and it was diagnosed as adenocarcinoma metastasis through fine-needle aspiration cytology. CT revealed swelling of left supraclavicular lymph nodes and para-aortic lymph nodes but no metastases to other organs. Exclusion diagnosis was performed, and they were diagnosed as multiple distant lymph node metastases. Chemotherapy(mFOLFOX6 plus bevacizumab) was started in December 2014, and all swollen lymph nodes shrank and disappeared on CT in July 2015. Furthermore, there was no swelling of lymph nodes or appearance of new lesions on CT in December 2015, as the response to treatment was judged to be complete. In addition, the regimen was changed to FOLFIRI plus bevacizumab because side effects such as peripheral neuropathy were worsening. Although chemotherapy was discontinued in November 2016, there has been no recurrence and a long-term complete response has been sustained.

A 43-year-old man who had no previous medical history or family history had positive fecal occult blood test in a local physician. Colonoscopy revealed a type 2 tumor of the ascending colon and a 10 mm submucosal tumor(SMT)of the lower rectum. Biopsy indicated moderately-differentiated adenocarcinoma of the ascending colon and neuroendocrine tumor (NET)of the lower rectum. No metastasis was detected by computed tomography. Therefore, the rectal SMT was resected first by endoscopic submucosal resection. Histopathologically, the lesion was localized in the submucosa and no lymphovascular invasion was found. Vertical margin was also negative. We decided not to perform additional intestinal resection for rectal NET. Thereafter, the patient underwent laparoscopic right hemicolectomy for ascending colon cancer. The histopathological findings were pT3, pN1, pM0, pStage Ⅲb. The patient received adjuvant chemotherapy. No relapse was found 18 months after surgery. We reported a rare case of a lower rectal NET with concomitant ascending colon cancer.

The case was a 67-year-old male, who underwent right hemicolectomy+D3 LN resection for ascending colon cancer at the age of 47, and pathological diagnosis was tub1tub2, T3, N0, M0, ly1, v1, Stage Ⅱa. 20 years after the first surgery, he visited our hospital for intermittent abdominal pain and abdominal fullness. CT scan showed stenosis and wall thickening at the anastomosis of the ileum and colon. When combining the detail examination by upper and lower gastrointestinal endoscopy and PET-CT scan, the tumor was clinically diagnosed asynchronous colon cancer, duodenal invasion. Partial resection of transverse colon and duodenal combined resection was performed. The pathological diagnosis was local recurrence of previous ascending colon cancer. Postoperative adjuvant chemotherapy was performed, but it was discontinued due to poor appetite. Currently, it has not recurred 7 months after the surgery. Recurrences more than 5 years after resection of colorectal cancer are rare, and reports of local recurrence are even rare. A long-term prognosis may be expected for early detection and treatment. Even if more than 5 years passed since the surgery, examination and treatment should be performed with recurrence in mind.

An 86-year-old woman’s stool sample was positive for blood. Computed tomography (CT) showed wall thickening of the ascending colon at the hepatic flexure. Colonoscopy showed near-complete obturation by colon cancer. Since she was asymptomatic, elective surgery was planned. Laparoscopic right hemicolectomy was performed. Histopathological examination showed poorly differentiated carcinoma cells proliferating in a solid pattern with marked lymphocyte infiltration. The diagnosis was lymphoepithelioma-like carcinoma (LELC) associated with Epstein-Barr virus (EBV) infection; however, EBV-encoded small RNA–in situ hybridization was negative. Microsatellite instability was not assessed. The postoperative course was uneventful and she was discharged on the 15th postoperative day. She remains recurrence-free at 2 years after surgery. Past reports note that colorectal carcinomas with dense lymphoid stroma may be related to LELC or medullary carcinoma (MC). Gastrointestinal LELC is rare, with some reports on LELC of the esophagus and stomach. Reports on LELC of the large intestine are very rare. MC of the large intestine is relatively new concept, firstly described in the WHO Classification of Tumours of the Digestive System 3rd Edition in 2000. We herein present a case of lymphoepithelioma-like carcinoma of the ascending colon and relevant case reports about LELC and MC of the large intestine.

Neuroendocrine neoplasms represent a broad group of uncommon tumours, comprising neuroendocrine tumours, mixed neuroendocrine non-endocrine neoplasms and neuroendocrine carcinomas. While most neuroendocrine neoplasms are well differentiated and exhibit indolent disease biology with excellent treatment response, neuroendocrine carcinomas represent a rare subtype with much more aggressive tumour behaviour, minimal response to adjuvant therapy and extremely poor prognosis. Herein, we report the case of a 47-year-old man who presented with a phlegmonous ascending colonic mass and associated calcified ileocolic lymphadenopathy. He underwent emergent right hemicolectomy, which diagnosed a T4aN2b neuroendocrine carcinoma. Within a week the patient displayed rapidly progressive locoregional nodal disease and he succumbed to disease within 5 weeks. We discuss the significance of calcified abdominal lymphadenopathy on computed tomography scans of the abdomen and review the literature surrounding this rare and highly fatal malignancy.

Patient: Male, 60-year-old Final Diagnosis: Colon mass • neuroendocrine tumor G3 Symptoms: Altered bowel habit • anemia Medication: — Clinical Procedure: Rt HemiColectomy Specialty: Oncology • Surgery Objective: Rare coexistence of disease or pathology Background: Gastrointestinal neuroendocrine tumors (NETs) are indolent hormone-secreting pathologic illnesses that can occur throughout the whole digestive tract. They are classified by site and grade. Colon neuroendocrine neoplasm (NEN) is an unusual histologic finding that needs to be further investigated. Well-differentiated (WD) Grade-3 (G3) is a new category of NEN that falls between neuroendocrine tumor (NET) and neuroendocrine carcinoma (NEC). Case Report: A 60-year-old man with a past medical history of diabetes mellitus presented with severe anemia and significant weight loss. Tumor markers (CEA and CA 19.9) were unremarkable. Colonoscopy showed a large fungating mass in the proximal part of the ascending colon. Biopsy results suggested colonic adenocarcinoma. Contrast-enhanced computed tomography of the chest, abdomen, and pelvis demonstrated a 5×5 cm ascending colon mass with few locoregional lymph nodes and no distant metastasis. A laparoscopic right hemicolectomy performed and histopathologic examination revealed T4N1, WD-NET G3. Postoperative completion work-up was done. Chromogranin-A was in the normal range and nuclear scans (PET and gallium 68) showed no abnormal uptake or residual disease. Extensive review, expert opinion, and multidisciplinary meetings failed to establish guidelines for adjuvant therapy due to the paucity of data in the literature. Conclusions: Well-differentiated grade 3 NETs of the ascending colon is a rare finding in a rare disease. This entity of NENs is an unmet medical issue on the border between NET and NEC that remains a matter of great debate in terms of establishing an accurate diagnosis and outlining proper management.

Gastric metastases (GMs) are rare and often accompanied with synchronous metastases of other organs. Synchronous isolated GMs from ascending colon carcinoma are uncommon and rarely studied. GMs may be confused with primary gastric tumors.A 45-year-old man presented to our hospital with abdominal distensionand anal pendant expansion. The abdominal physical examination was negative. The positive fecal occult blood test and the negative tumor marker were obtained. Colonoscopy and gastroduodenoscopy revealed a polypoidal lesion in the ascending colon and a polypoid mass in the gastric body, respectively. CT showed the thickened wall of ascending colon and polypoid mass in the gastric body with homogenous enhancement. Additionally, synchronous gastric metastases from the ascending colon carcinoma were confirmed by pathology after laparoscopic right hemicolectomy and partial gastrectomy. After 13 individual doses of fluorouracil (2.8 g/time), calcium leucovorin (0.8 g/time), and oxaliplatin (85 mg/time), the patient was discharged without any discomfort, without any additional metastases detected during the following 18 months.1.A rare case of synchronous isolated gastric metastasis from ascending colon carcinoma was confirmed by computed tomography (CT) and pathological diagnosis.GM may appear as a polypoid lesion. Surgery combined with chemotherapy may improve the prognosis in patients with synchronous isolated GM.

Several studies recommend that colonic hepatic flexure (CHF) should be mobilized preliminarily in minimally invasive pancreaticoduodenectomy (PD). However, there are little data to support that preferential mobilization of the CHF can positively affect the perioperative events of PD. We aimed to assess the effect of preferential mobilization of the CHF in PD.A retrospective cohort study of patients who underwent PD was performed between 2016 and 2019. Clinical characteristics, operative data, and postoperative surgical complications were recorded.The study included 668 patients; 486 patients underwent open pancreaticoduodenectomy (OPD) and 182 patients underwent laparoscopic pancreaticoduodenectomy (LPD). Patients were divided into CHF-M (OPD, n=129; LPD, n=95) and conventional (OPD, n=357; LPD, n=87) groups according to preferential CHF mobilization. There were no differences between the groups regarding most demographics. Within patients who underwent OPD, decreased estimated blood loss (EBL) (251.2±146.4 vs. 307.3±173.5 mL, P0.05) was observed in CHF-M group. Within patients who underwent LPD, operative time (328.7±66.3 vs. 406.5±85.5 min, P0.001), EBL (166.8±96.4 vs. 271.8±130.7 mL, P0.001), the incidence of clinically relevant pancreaticfistula (7.4% vs. 23.0%, P0.05), and length of stay (12.3±5.1 vs. 16.0±7.4 d, P0.05) were decreased in CHF-M group. Moreover, patients with high body mass index who underwent LPD showed more significant differences in operative time (336.0±67.7 vs. 431.9±79.1, P0.001) and EBL (179.6±97.8 vs. 278.2±135.6, P0.001) between groups.We first demonstrated that preferential mobilization of the CHF can facilitate PD. The patients who underwent minimally invasive surgery and the patients with high body mass index may benefit more from this technique.

The precaecocolic fascia, previously known as Jackson's membrane, is a variable vascular peritoneal fold between the ascending colon and the right posterolateral abdominal wall. First described in 1913, it was originally thought to be of developmental or inflammatory origin and associated with abdominal pain. This investigation aimed to review its frequency, form and structure and look for evidence of association with malformation of the bowel, or previous inflammation. 26 dissecting room cadavers were studied to identify the precaecocolic fascia, any malrotation of the colon or signs of previous inflammation: adhesions, surgical scars, or absence of the appendix. Its structure was examined histologically and latex injections were used to trace the arteries. Membranes comparable with previous descriptions of the precaecocolic fascia occurred in 12 of 26 abdomens. They varied in form and size from long and translucent to short, thick, and opaque. In structure, the fascia resembled a fold of peritoneum containing a thickened fibrous lamina. Large thin-walled arteries in the fascia crossed the arteries in the wall of the colon at the point of attachment. No significant association with colonic malrotation or markers of previous inflammation were found. Attention should be paid to the definition of the precaecocolic fascia and "membrane" seems a more appropriate term than "fascia". It is one of a recognized group of peritoneal folds/bands, doubtful in origin but unlikely to be post-inflammatory. It may modify colonic mobility or complicate colonic operations.

The hepatic flexure and transverse colon have a complex intermingled lymphovascular anatomy crossing between mesocolon and mesogastrium. Few studies have investigated the oncological relevance of metastatic infrapyloric and gastroepiploic lymph nodes (IGLN) from hepatic flexure and transverse colon tumors. This study aimed to evaluate the incidence and risk factors for IGLN metastases, and the indications, surgical morbidities, and oncological outcome following extended lymphadenectomy.According to the PRISMA statement, a systematic review on IGLN lymphadenectomy for colon cancer was conducted into PubMed, Embase, and Cochrane databases. A critical appraisal of study was performed according to the Joanna Briggs Institute Tools.Nine studies were included. IGLN metastases incidence ranged 0.7-22%. IGLN positivity for patients with metastatic mesocolic lymph nodes ranged 1.7-33.3%. Postoperative complication rate ranged 8.5-36.9%, mostly low grade according to Clavien-Dindo's classification. Postoperative mortality rate ranged 0-5.4% at 30-days. IGLN metastases were associated with advanced disease with a 5-year progression-free survival rate up to 33.9%. Two authors reported perineural invasion and N stage as risk factors, while another reported endoscopic obstruction, signet ring adenocarcinoma, CEA level ≥17 ng/ml, and M1 stage to be risk factors for IGLN involvement. Apart from one study, all other studies were of moderate/high quality.Metastatic IGLNs are not uncommon and should be highly considered. IGLN metastases could be potentially associated with an aggressive disease. IGLN dissection is not associated with higher morbidity and mortality than standard CME. Preoperative risk factors of IGLN involvement could guide surgical indication for extended lymphadenectomy.

Although trichuriasis, a zoonotic disease, has recently become rare in Japan due to improved environmental hygiene, we herein report a 79-year-old man in whom a worm was incidentally found in the ascending colon during colonoscopy for positive fecal occult blood and was endoscopically removed. A genetic analysis identified the worm as Trichuris trichiura possessing mixed sequences from non-human primate and human origins. Despite controversy regarding Trichuris trichiura infection originating from Japanese macaques, according to some studies, it originates primarily from humans. This report suggests the efficacy of a genetic analysis for identifying infection sources.

The case of a patient with ascending colon cancer and infiltration of the abdominal wall with a proliferative tumor on the skin is presented. This is an 83-year-old man who underwent surgery for an intra-abdominal abscess ten months before admission and develops a colocutaneous fistula. The patient presented a 10 cm diameter proliferative, multilobed, non-painful tumor on the flank and right iliac fossa; the biopsy revealed an adenocarcinoma. The colonoscopy revealed a 6 cm tumor in the ascending colon, the biopsy reported moderately differentiated adenocarcinoma. The tomography showed a neoformative lesion in the ascending colon and cecal region with dimensions of 52x46x44 mm with a 62 mm colocutaneous tumor course that ended at the cutaneous level in a 70 mm ovoid lesion. A right colectomy was performed with en bloc resection of the abdominal wall compromised by the tumor. The relationship between skin infiltration and a history of laparoscopic surgical drainage of an intraperitoneal abscess apparently caused as a complication of ascending colon cancer almost one year before admission is postulated. The drain used served as a route for infiltration into the abdominal wall.

Colorectal cancer (CRC) is the third most frequent cancer in the world and the second cause of death of neoplastic origin. Synchronism in CCR is approximately 3-6%. The gastrointestinal tract is the most frequent place where neuroendocrine neoplasms (NNE) settle and a special type of these neuroendocrine carcinomas (CNE) are rare. Treatment is challenging, due to the aggressiveness of the malignancy and the lack of well-established protocols. Therefore a multidisciplinary approach is needed, however, in most cases the result is not the best. We present the case of an 83-year-old man who has an emergency with a 3-month history of diarrhea, perianal pain, weight loss, and hematochezia. The endoscopic study shows evidence of two malignancies and the histological study confirms the presence of CNE in small cells at the rectum and adenocarcinoma in the ascending colon. He underwent systematic chemotherapy, however, he evolved unfavorably, dying after 3 weeks.

Patient: Female, 63-year-old Final Diagnosis: Cardiac metastasis Symptoms: Dyspnea Medication:— Clinical Procedure: Surgery Specialty: Oncology Objective: Unusual clinical course Background: Malignant tumors, such as lung and breast cancers, can metastasize to the heart. However, cardiac metastasis rarely occurs in colorectal cancer. Cardiac metastasis cases are typically asymptomatic and rarely cause cardiac tamponade. Heart failure due to systemic metastasis is a terminal symptom; therefore, cardiac metastasis is rarely diagnosed when a patient is alive. We report a case of stage II ascending colon cancer with cardiac tamponade due to pericardial metastasis. Case Report: The patient was a 63-year-old woman who underwent laparoscopic ileocecal resection for ascending colon cancer. The final pathological diagnosis was stage IIB cancer. At the time of surgery, computed tomography scans revealed no metastases to the regional lymph nodes, liver, lungs, and other organs. The patient was then referred for dyspnea 5 months after the surgery. Computed tomography revealed large quantities of pericardial effusion, and the patient was diagnosed with cardiac tamponade. The symptoms were alleviated after pericardiocentesis. Cytological examination of the pericardial fluid confirmed the diagnosis of adenocarcinoma, and by extension, cardiac metastasis of the ascending colon cancer. Anticancer agents were recommended, but the patient opted for palliative treatment. Conclusions: We report a rare case of ascending colon cancer with pericardial metastasis. The advancements in chemotherapy have made the prognosis of colorectal cancer more favorable. The prevalence of pericardial metastasis is expected to increase as well. As such, it is necessary to discuss similar case encounters and establish appropriate treatment.

Background: Minimally invasive colectomy has become the standard for treatment of colonic disease in many centers. Restoration of bowel continuity following resection can be achieved by intracorporeal (IC) or extracorporeal (EC) anastomosis. The aim of this systematic review was to assess the outcomes of IC compared to EC anastomosis in minimally invasive right colectomy. Methods: A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant systematic literature search for studies assessing the outcome of IC and EC anastomosis in laparoscopic and robot-assisted right colectomy was conducted. The primary outcome of this review was postoperative complications. Secondary outcomes included operative time, blood loss, length of stay, conversion to open surgery, and bowel recovery. Results: Twenty-five studies including 4450 patients were evaluated. 47.7% of patients had IC anastomosis and 52.3% had EC anastomosis. The weighted mean length of extraction site incision in the IC group was shorter than the EC group. The EC group had significantly higher odds of conversion to open surgery (OR 1.87, 95% CI 1–3.45, p = 0.046), total complications (OR 1.54, 95% CI 1.05–2.11, p = 0.007), anastomotic leakage (AL) (OR 1.95, 95% CI 1.4–2.7, p = 0.003), surgical site infection (SSI) (OR 1.69, 95% CI 1.4–2.6, p = 0.002), and incisional hernia (OR 3.14, 95% CI 1.85–5.33, p < 0.001) compared to the IC group. Both groups had similar rates of ileus, small bowel obstruction, bleeding, and intra-abdominal infection. Conclusion: IC anastomosis was associated with significantly shorter extraction site incisions, earlier bowel recovery, fewer complications, and lower rates of conversion, AL, SSI, and incisional hernia than has the EC anastomosis.

Undifferentiated pleomorphic sarcoma (UPS) is a soft tissue sarcoma, occurring most commonly on the lower extremities. We herein report a rare case of primary UPS adjacent to the ascending colon and in the right iliopsoas muscle. Computed tomography of the abdomen revealed large masses, and the patient experienced a high-grade fever, leukocytosis, elevated serum C-reactive protein level, and hematopoietic activation on 18F-fluorodeoxyglucose-positron emission tomography. This inflammatory reaction was caused by granulocyte colony-stimulating factor secreted by tumor cells. Surgical resection was performed, and the inflammatory reaction disappeared immediately. The patient received adjuvant chemotherapy and survived one year after the operation without evidence of recurrence.

Recent studies have demonstrated that the protective effect of colonoscopy against colorectal cancer is lower in the proximal colon. Proximal serrated polyps, including sessile serrated adenomas and proximal hyperplastic polyps, can be frequently missed and pose a risk of interval cancers. To investigate the overall adenoma detection rate (ADR) and the proximal serrated polyp detection rate (PSPDR) among academic gastroenterologists, community gastroenterologists, and colorectal surgeons from a single institution, all of whom have received formal training in colonoscopy during their fellowship. All complete screening colonoscopies for patients aged 50 or older with a good to excellent bowel preparation performed by different endoscopists at Medstar Washington Hospital Center (Washington, DC) from July 2015 to December 2017 were reviewed. Pathology reports of the resected polyps were manually reviewed. A total of 2850 screening colonoscopies meeting the inclusion criteria were performed by 18 endoscopists (6 academic, 7 community, and 5 colorectal surgeons). There was no significant difference in the mean ADR among the three groups of endoscopists: academic gastroenterologists, community gastroenterologists, and colorectal surgeons (40.3% vs 36.0% vs 39.6%, respectively). However, academic gastroenterologists had a significantly higher PSPDR compared to community gastroenterologists or colorectal surgeons (12.3% vs 5.4% vs 4.5%, respectively, ANOVA p = 0.006). Our novel data show that academic gastroenterologists had a significantly higher PSPDR compared to community gastroenterologists or colorectal surgeons despite a comparable overall ADR among the three groups. PSPDR may be considered as an important quality indicator for colonoscopy, apart from ADR.

Introduction Laparoscopic colorectal surgery is increasingly performed worldwide due to its multiple advantages over traditional open surgery. In the surgical treatment of right-sided colonic tumours, the latest technique is laparoscopic right hemicolectomy with complete mesocolic excision (lapCME), which aims to lower the rate of local recurrence and maximise survival as compared to standard laparoscopic right hemicolectomy (lapS). Methods We conducted a retrospective analysis of our initial experience with lapCME in Singapore General Hospital between 2012 and 2015. All procedures were performed by a single surgeon. Results Nine patients underwent lapCME and 16 patients underwent lapS. Indication for lapCME was cancer in the right colon. None of the patients required conversion to open surgery, and all were discharged well. The number of lymph nodes resected in the lapCME group was significantly greater than in the lapS group (29 ± 15 vs. 19 ± 6; p = 0.02) during the study period, and the mean operation time was significantly longer for lapCME (237 ± 50 minutes vs. 156 ± 46 minutes; p = 0.0005). There were no statistically significant differences in terms of demographics, tumour stage, time taken for bowel to open postoperatively, time taken for patient to resume a solid diet postoperatively and length of hospital stay. Two patients who underwent lapS were re-admitted for intra-abdominal collections - one patient required radiology-guided drainage, while the other patient was managed conservatively. Conclusion Our initial experience with lapCME confirms the feasibility and safety of the procedure.

Background Up to 30% of colorectal cancers develop through the serrated pathway. African Americans (AAs) suffer a disproportionate burden of colorectal cancer. The aim of this study was to evaluate clinicopathological features of AA patients diagnosed with sessile serrated polyps (SSPs). Methods We conducted a retrospective study of all colonoscopies (n = 12,085) performed at Howard University Hospital, from January 1st, 2010 to December 31st, 2015, of which 83% were in AA patients, (n = 10,027). Among AAs, pathology reports confirmed 4070 patients with polyps including 252 with SSPs. Demographic and clinical variables (i.e. sex, age, BMI, anatomic location, clinical symptoms, polyp size, and clinical indications were collected at colonoscopy. Results In the AA population, the median age was 56 with interquartile range (IQR) of 51 to 62 years, 54% were female, and 48% had a BMI > 30. The most common reason for colonoscopy was screening (53%), whereas the prevalent reasons for diagnostic colonoscopies were changes in bowel habits (18%) and gastrointestinal bleeding (17%). The total number of SSPs among the 252 AA (diagnosed with SSPs) was 338. Of these, 9% (n = 29/338) had some degree of cytological dysplasia, primarily in the ascending colon (n = 6/42, 14%), Transverse colon (n = 2/16, 13%) and rectosigmoid (n = 19/233, 8%). About 24% of patients had more than 2 polyps. Most patients (76%) had distal SSPs (rectal and rectosigmoid), in comparison to 14% of proximal polyps and 10% of bilateral locations. Median SSA/P size for all locations was 0.6 cm. Conclusion The prevalence of SSPs accounts for 6% of all polyps in AA patients and was diagnosed in 2.5% of all colonoscopies (n = 252/10,027), which is higher than Caucasians in the US. SSPs were predominantly located in the left side, as compared to published literature showing the predominance in the right side of the colon. Screening of CRC will have the chance to detect high risk SSA/P in this population.

Background Severe haemorrhage is an uncommon but life-threatening complication of ulcerative colitis (UC). Superselective transcatheter embolization has shown to be an effective and safe therapeutic modality in patients with lower gastrointestinal bleeding of various aetiologies; nevertheless, its role in UC-related acute bleeding is unknown. Cases presentation Efficacy and safety of selective transcatheter arterial embolization in three consecutive UC patients diagnosed with massive haemorrhage admitted in a tertiary institution are reported. In all patients computed tomography scan showed active arterial haemorrhage from ascendant or sigmoid colon; subsequent arteriography demonstrated active arterial bleeding from colic branches of the superior or inferior mesenteric arteries, and selective transcatheter embolization was performed with immediate technical success in all three cases. Nevertheless, rebleeding requiring subtotal colectomy occurred between 5 h and 6 days after the procedure. Conclusions Transcatheter arterial embolization is not an effective therapeutic approach in UC patients with severe, acute colonic haemorrhage. Colectomy should not be delayed in this setting.

Appropriate colonoscopy withdrawal times for individual colonic segments are not well known. The relationship between withdrawal time and adenoma detection rate (ADR)/polyp detection rate (PDR) in individual colonic segments was examined in this study.This was a prospective observational study involving 724 patients who underwent colonoscopy screening or surveillance colonoscopy from October 2015 to February 2017 at 10 university hospitals.In the right side of the colon, the ADR (33.2% vs 13.7%, P .001), PDR, serrated polyp detection rate, and number of adenomas per colonoscopy (APC) were significantly higher when the colonoscopy withdrawal time was ≥2 minutes compared with 2 minutes. When the withdrawal time was ≥4 minutes in the proximal colon and ≥3 minutes in the left segment of the colon, the ADR, PDR, and APC were significantly higher compared with withdrawal times of 4 minutes and 3 minutes, respectively. Multivariate analyses showed that the ADR was significantly associated with withdrawal times of ≥2 minutes in the right side of the colon (odds ratio [OR], 2.98; 95% confidence interval [CI], 1.72-5.15; P .001), ≥4 minutes in the proximal colon (OR, 4.48; 95% CI, 3.15-6.36; P .001), and ≥3 minutes in the left segment of the colon (OR, 2.92; 95% CI, 1.74-4.91; P .001).The PDR and ADR appeared to be significantly increased when the withdrawal time was ≥2 minutes in the right-sided colon segment, ≥4 minutes in the proximal colon, and ≥3 minutes in the left-sided colon segment compared with shorter withdrawal times.