Oncologic safety of laparoscopic surgery after metallic stent insertion for obstructive left-sided colorectal cancer: a multicenter comparative study.

BACKGROUND: Self-expanding metallic stents (SEMSs) are used as a bridge to surgery in patients with obstructive colorectal cancer. However, the role of laparoscopic resection after successful stent deployment is not well established. We aimed to compare the oncologic outcomes of laparoscopic vs open surgery after successful colonic stent deployment in patients with obstructive left-sided colorectal cancer. METHODS: In this multicenter study, 179 (97 laparoscopy, 82 open surgery) patients with obstructive left-sided colorectal cancer who underwent radical resection with curative intent after successful stent deployment were retrospectively reviewed. To minimize bias, we used inverse probability treatment-weighted propensity score analysis. The short- and long-term outcomes between the groups were compared. RESULTS: Both groups had similar demographic and tumor characteristics. The operation time was longer, but the degree of blood loss was lower in the laparoscopy than in the open surgery group. There were nine (9.3%) open conversions. After adjustment, the groups showed similar patient and tumor characteristics. The 5-year disease-free survival (DFS) (laparoscopic vs open: 68.7% vs 48.5%, p = 0.230) and overall survival (OS) (laparoscopic vs open: 79.1% vs 69.0%, p = 0.200) estimates did not differ significantly across a median follow-up duration of 50.5 months. Advanced stage disease (DFS: hazard ratio [HR] 1.825, 95% confidence interval [CI]: 1.072-3.107; OS: HR 2.441, 95% CI 1.216-4.903) and post-operative chemotherapy omission (DFS: HR 2.529, 95% CI 1.481-4.319; OS: HR 2.666, 95% CI 1.370-5.191) were associated with relatively worse long-term outcomes. CONCLUSION: Stent insertion followed by laparoscopy with curative intent is safe and feasible; the addition of post-operative chemotherapy should be considered after successful treatment.

Quality of life after sphincter preservation surgery or abdominoperineal resection for low rectal cancer (ASPIRE): A long-term prospective, multicentre, cohort study.

BACKGROUND: The long-term effects of radical resection on quality of life may influence the treatment selection. The objective of this study was to determine whether abdominoperineal resection has a better effect on the quality of life than sphincter preservation surgery at 3 years after surgery. METHODS: This prospective, cohort study included patients who underwent radical resection for low rectal cancer. The primary outcomes were European Organisation for Research and Treatment of Cancer QLQ-C30 and CR38 quality of life scores 3 years after surgery, which were compared with linear generalised estimating equations, after adjustment for baseline values, a time effect, and an interaction effect between time and treatment. The secondary outcomes included sexual-urinary functions and oncological outcomes. The study was registered with ClinicalTrials.gov (NCT01461525). FINDINGS: Between December 2011 and August 2016, 342 patients were enrolled: 268 (78•4%) underwent sphincter preservation surgery and 74 (21•6%) underwent abdominoperineal resection. The global quality of life scores did not differ between sphincter preservation surgery and abdominoperineal resection groups (adjusted mean difference, 4•2 points on a 100-point scale; 95% confidence interval  [CI], -1•3 to 9•7, p = 0•1316). Abdominoperineal resection was associated with a worse body image (9•8 points; 95% CI, 2•9 to 16•6, p = 0•0052), micturition symptoms (-8•0 points; 95% CI, -14•1 to -1•8, p = 0•0108), male sexual problems (-19•9 points; 95% CI, -33•1 to -6•7, p = 0•0032), less confidence in getting and maintaining an erection in males (0•5 points on a 5-point scale; 95% CI, 0•1 to 0•8, p = 0•0155), and worse urinary symptoms (-5•4 points on a 35-point scale; 95% CI, -8•0 to -2•7, p < 0•0001). The 5-year overall survival was worse with abdominoperineal resection in unadjusted (92•2% vs 80•9%; difference 11•3%, hazard ratio 2•38; 95% CI, 1•27 to 4•46, p = 0•0052), but did not differ after adjustment. INTERPRETATION: In this long-term prospective study, abdominoperineal resection failed to meet the superiority to sphincter preservation surgery in terms of quality of life. Although the global quality of life scores did not differ between groups, this study suggests that sphincter preservation surgery can be an acceptable alternative to abdominoperineal resection for low rectal cancer, offering a better quality of life and sexual-urinary functions, with no increased oncological risk even after 3 years. FUNDING: Seoul National University Bundang Hospital, Korea.

Nomogram Development and External Validation for Predicting the Risk of Lymph Node Metastasis in T1 Colorectal Cancer.

PURPOSE: Predicting lymph node metastasis (LNM) risk is crucial in determining further treatment strategies following endoscopic resection of T1 colorectal cancer (CRC). This study aimed to establish a new prediction model for the risk of LNM in T1 CRC patients. MATERIALS AND METHODS: The development set included 833 patients with T1 CRC who had undergone endoscopic (n=154) or surgical (n=679) resection at the National Cancer Center. The validation set included 722 T1 CRC patients who had undergone endoscopic (n=249) or surgical (n=473) resection at Daehang Hospital. A logistic regression model was used to construct the prediction model. To assess the performance of prediction model, discrimination was evaluated using the receiver operating characteristic (ROC) curves with area under the ROC curve (AUC), and calibration was assessed using the Hosmer-Lemeshow (HL) goodness-of-fit test. RESULTS: Five independent risk factors were determined in the multivariable model, including vascular invasion, high-grade histology, submucosal invasion, budding, and background adenoma. In final prediction model, the performance of the model was good that the AUC was 0.812 (95% confidence interval [CI], 0.770 to 0.855) and the HL chi-squared test statistic was 1.266 (p=0.737). In external validation, the performance was still good that the AUC was 0.771 (95% CI, 0.708 to 0.834) and the p-value of the HL chi-squared test was 0.040. We constructed the nomogram with the final prediction model. CONCLUSION: We presented an externally validated new prediction model for LNM risk in T1 CRC patients, guiding decision making in determining whether additional surgery is required after endoscopic resection of T1 CRC.

Oncologic outcomes of preoperative stent insertion first versus immediate surgery for obstructing left-sided colorectal cancer.

BACKGROUND: Colonic self-expanding metallic stenting (SEMS) is widely used for the treatment of malignant colonic obstruction as a bridge to elective surgery. However, the effects of colonic stenting on long-term oncologic outcomes are debatable. This study aimed to compare the long-term oncologic outcomes of preoperative SEMS insertion with those of immediate surgery in patients with obstructing left-sided colorectal cancer. METHODS: A cohort of consecutive patients who underwent radical surgery for obstructing left-sided colorectal cancer between 2004 and 2011 in five tertiary referral hospitals were analyzed. Long-term survivals were analyzed and adjusted using the inverse probability of treatment weighting method, based on propensity scores, to reduce selection bias. RESULTS: One hundred and nine patients underwent immediate surgery, and 226 underwent stent insertion before surgery. Disease-free survival did not differ significantly in both the unadjusted population (hazard ratio [HR] 1.063, 95% confidence interval [CI] 0.730-1.548; Log-rank, p = 0.746) and the adjusted population (HR 0.122, 95% CI 0.920-1.987; Log-rank, p = 0.122). Overall survival also did not differ significantly in both the unadjusted population (HR 0.871, 95% CI 0.568-1.334; Log-rank, p = 0.526) and the adjusted population (HR 1.023, 95% CI 0.665-1.572; Log-rank, p = 0.916). Defunctioning stoma formation was less in the SEMS insertion group than immediate surgery group (adjusted, 14.6% vs. 41.3%, p < 0.001). CONCLUSION: The 'bridge to surgery' strategy using metallic stents was oncologically comparable to immediate surgery in patients with malignant left-sided colorectal obstruction.

Composite intestinal adenoma-microcarcinoid in the colon and rectum: a case series and historical review.

BACKGROUND: Composite intestinal adenoma-microcarcinoid (CIAM) is a rare colorectal lesion that mostly comprises a conventional adenomatous component with a minute proportion of neuroendocrine (NE) component. Although microcarcinoids are well-recognized in the setting of chronic inflammatory disorders of the gastrointestinal tract, large intestinal microcarcinoids associated with intestinal adenoma are exceedingly rare and their clinicopathologic characteristics are yet to be elucidated. This study was performed to clarify their clinicopathologic characteristics and to review the relevant literature. METHODS: In total, 24 cases of CIAM in which tumors were excised endoscopically (n = 22) or surgically (n = 2) were retrieved from the Department of Pathology, Daehang Hospital. We analyzed their clinicopathologic characteristics and performed immunohistochemical staining for NE markers to determine their endocrine nature. RESULTS: CIAM usually developed in middle-aged and elderly patients, with a mean age of 62.0 years (range, 44-81 years). Thirteen patients were men and 11 were women, indicating a nearly equal sex ratio. Unlike classic carcinoid tumors, CIAMs occurred mostly in the colon (83.3% of cases), particularly in the proximal colon. Histologically, the microcarcinoid component consisted of low-grade NE cells arranged in small nests, glands or cords interspersed with glandular elements or less frequently resembled squamous morules. There was no expansile nodular or organoid growth pattern, which is typical of carcinoid tumors. The microcarcinoids were 1-20 mm in size (mean size, 4.7 mm) and were mostly situated in the basal lamina propria with no submucosal layer involvement; none showed desmoplastic reaction or increased proliferative activity. Follow-up data (mean, 23.1 months) were available for 18 patients; all patients are alive and well. CONCLUSIONS: To the best of our knowledge, ours is the largest series of patients with CIAM in the English-language literature. Microcarcinoids found in CIAMs appear to show favorable clinical outcomes regardless of their size, likely due to the absence of submucosal extension and/or increased proliferative activity. We recommend avoiding additional radical surgeries in patients who have endoscopically undergone complete CIAM excision unless they exhibit ominous histologic features such as submucosal extension or increased proliferative activity.

Comparative Evaluation of the Efficacy of Polyethylene Glycol With Ascorbic Acid and an Oral Sulfate Solution in a Split Method for Bowel Preparation: A Randomized, Multicenter Phase III Clinical Trial.

BACKGROUND: An adequate level of bowel preparation before colonoscopy is important. The ideal agent for bowel preparation should be effective and tolerable. OBJECTIVE: The purpose of this study was to compare the clinical efficacy and tolerability of polyethylene glycol with ascorbic acid and oral sulfate solution in a split method for bowel preparation. DESIGN: This was a prospective, multicenter, randomized controlled clinical trial. SETTINGS: Outpatients at the specialized clinics were included. PATIENTS: A total of 186 subjects were randomly assigned. After exclusions, 84 subjects in the polyethylene glycol with ascorbic acid group and 83 subjects in the oral sulfate solution group completed the study and were analyzed. INTERVENTIONS: Polyethylene glycol with ascorbic acid or oral sulfate solution in a split method was the included intervention. MAIN OUTCOME MEASURES: The primary end point was the rate of successful bowel preparation, which was defined as being excellent or good on the Aronchick scale. Tolerability and adverse events were also measured. RESULTS: Success of bowel preparation was not different between 2 groups (91.7% vs 96.4%; p = 0.20), and the rate of adverse GI events (abdominal distension, pain, nausea, vomiting, or abdominal discomfort) was not significantly different between the 2 groups. In contrast, the mean intensity of vomiting was higher in the oral sulfate solution group than in the polyethylene glycol with ascorbic acid group (1.6 ± 0.9 vs 1.9 ± 1.1; p = 0.02). LIMITATIONS: All of the colonoscopies were performed in the morning, and the subjects were offered enhanced instructions for bowel preparation. In addition, the results of tolerability and adverse effect may have a type II error, because the number of cases was calculated for confirming the efficacy of bowel preparation. CONCLUSIONS: Oral sulfate solution is effective at colonoscopy cleansing and has acceptable tolerability when it is compared with polyethylene glycol with ascorbic acid. The taste and flavor of oral sulfate solution still need to be improved to enhance tolerability.

Persistent Bleeding Following a Stapled Hemorrhoidopexy.

A stapled hemorrhoidopexy (SH) is widely used for treatment of patients with grades III and IV hemorrhoids. The SH is easy to perform, is associated with less pain and allows early return to normal activities. However, complications, whether severe or not, have been reported. Here, we present the case of a female patient with persistent bleeding after a SH. The bleeding was caused by the formation of granulation tissue at the stapler line, diagnosed with sigmoidoscopy, and successfully treated via transanal excision (TAE) under spinal anesthesia. The biopsy showed inflammatory granulation tissue. After the TAE, her symptom was completely gone.

Early Outcomes of Endoscopic Submucosal Dissection for Colorectal Neoplasms According to Clinical Indications.

BACKGROUND: Although endoscopic submucosal dissection has been shown to be safe and effective for colorectal tumors, its clinical outcomes vary. OBJECTIVE: The aim of this study is to assess the outcomes of endoscopic submucosal dissection according to clinical indications. DESIGN: This is a prospective, multicenter, single-arm study. SETTING: The study was conducted at special hospitals for colorectal diseases and cancers. PATIENTS: The study population included consecutive patients aged 20 to 80 years who underwent colorectal endoscopic submucosal dissection for 1) early colorectal cancer, 2) laterally spreading tumors ≥2 cm in diameter, and 3) submucosal tumors. INTERVENTIONS: Procedures were performed by experienced colonoscopists. MAIN OUTCOME MEASURES: The primary end points were en bloc and curative resection rates. En bloc resection was defined as endoscopic one-piece resection without tumor fragmentation. Curative resection was defined as en bloc resection and no pathologic requirement for additional surgery. Secondary end points included procedure time, complications, and hospital stay. RESULTS: Of 321 patients, 317 (98.8%) underwent en bloc resection and 231 (72.0%) underwent curative resection. The mean procedure time was 46.2 minutes. Mean hospital stay after the procedure was 3.1 days. Perforation occurred in 2 patients (0.6%), and bleeding occurred in 10 (3.1%) patients. All patients with complications were treated by endoscopic clipping or nonoperative management. Fifteen patients (4.7%) underwent additional radical surgery owing to the risks of lymph node metastasis. Although tumor size was smaller and procedure time shorter in the submucosal tumor group than in the laterally spreading tumor or early colorectal cancer group, there were no differences in clinical outcomes including en bloc and curative resection rates. Submucosal fibrosis was the only factor affecting endoscopic submucosal dissection procedure-related complications. LIMITATIONS: Early outcomes in a limited population and the potential for selection bias were limitations of this study. CONCLUSIONS: Outcomes of colorectal endoscopic submucosal dissection were acceptable in selected patients, with no difference in outcomes according to clinical indications. Because submucosal fibrosis can increase complications, it should be minimized before endoscopic submucosal dissection.

Comparison of long-term oncological outcomes of appendiceal cancer and colon cancer: A multicenter retrospective study.

BACKGROUND: There has been no comparative study of the long-term oncological outcomes of appendiceal cancer and colon cancer. We hypothesized that the oncological outcome is worse in appendiceal cancer because perforation is more frequent than in colon cancer. METHODS: Patients with stage I-III were selected from 5046 patients with appendiceal or colon cancer, between September 2001 and June 2010. The 5-year disease-free survival (DFS) was the primary endpoint. Multivariate analyses with Cox proportional hazards model for DFS and logistic regression model for perforation were conducted. A matching model was used to compensate for the heterogeneity between groups. RESULTS: The perforation rate was 44.7% in appendiceal cancer (n = 47), but 1.1% in colon cancer (n = 2828) (p = 0.001). The 5-year DFS rate was lower in appendiceal cancer than in colon cancer (57.9% vs. 85.2%, p = 0.001; matching model, 54.2% vs. 78.4%, p = 0.038), with a higher rate of peritoneal seeding (25.5% vs. 2.5%, p = 0.001; matching model, 24.0% vs. 4.0%, p = 0.007). Multivariate Cox regression showed that appendiceal cancer was an independent prognostic factor for poor DFS (hazard ratio = 2.602, 95% confidence interval = 1.26-5.35, p = 0.009), and logistic regression confirmed that appendiceal cancer was the risk factor associated with perforation (odds ratio = 66.265, 95% confidence interval = 28.21-155.61, p = 0.001). CONCLUSIONS: This study suggested that the long-term oncological outcomes are worse for appendiceal cancer than for colon cancer, attributed to higher perforation rate in appendiceal cancer.

Reappraisal of hMLH1 promoter methylation and protein expression status in the serrated neoplasia pathway.

AIMS: The aim of this study was to determine whether human mutL homologue 1 (hMLH1) inactivation precedes the progression of sessile serrated lesion (SSL) into SSL with cytological dysplasia (SSL/D) and to define the histological stage at which promoter methylation and inactivation of hMLH1 occur. METHODS AND RESULTS: Using the MassARRAY EpiTYPER assay and immunohistochemistry, we examined methylation levels and the protein expression status of hMLH1 in 33 SSL/Ds with conventional epithelial dysplasia and compared the results with those of control hyperplastic polyps (HPs) and SSLs. The methylation level of hMLH1 was higher in the dysplastic component than in the non-dysplastic component of SSL/Ds (P = 0.005), and differed significantly with regard to the degree of dysplasia (P = 0.002). The methylation levels of hMLH1 in the dysplastic component of SSL/Ds tended to be higher than those of control SSLs and HPs (P = 0.063 and P = 0.017, respectively). The loss of hMLH1 protein expression was identified in only 13 of 33 (39.39%) dysplastic components of SSL/Ds. CONCLUSION: Promoter methylation and loss of protein expression of hMLH1 are not parallel processes that occur concurrently. hMLH1 methylation is an early molecular event which occurs even in HP. However, the loss of hMLH1 expression is a much later step, found in approximately 40% of SSL/Ds at various histological stages. Notably, the loss of hMLH1 protein expression does not necessarily precede the development of cytological dysplasia in SSL.

Clinical impact of atypical endoscopic features in rectal neuroendocrine tumors.

AIM: To validate the association between atypical endoscopic features and lymph node metastasis (LNM). METHODS: A total of 247 patients with rectal neuroendocrine tumors (NETs) were analyzed. Endoscopic images were reviewed independently by two endoscopists, each of whom classified tumors by sized and endoscopic features, such as shape, color, and surface change (kappa coefficient 0.76 for inter-observer agreement). All of patients underwent computed tomography scans of abdomen and pelvis for evaluation of LNM. Univariate and multivariate analyses were performed to identify the factors associated with LNM. Additionally, the association between endoscopic atypical features and immunohistochemical staining of tumors was analyzed. RESULTS: Of 247 patients, 156 (63.2%) were male and 15 (6.1%) were showed positive for LNM. On univariate analysis, tumor size (P < 0.001), shape (P < 0.001), color (P < 0.001) and surface changes (P < 0.001) were significantly associated with LNM. On multivariate analysis, tumor size (OR = 11.53, 95%CI: 2.51-52.93, P = 0.002) and atypical surface (OR = 27.44, 95%CI: 5.96-126.34, P < 0.001) changes were independent risk factors for LNM. The likelihood of atypical endoscopic features increased as tumor size increased. Atypical endoscopic features were associated with LNM in rectal NETs < 10 mm (P = 0.005) and 10-19 mm (P = 0.041) in diameter. Immunohistochemical staining showed that the rate of atypical endoscopic features was higher in non L-cell tumors. CONCLUSION: Atypical endoscopic features as well as tumor size are predictive factors of LNM in patients with rectal NETs.

Sessile serrated adenoma/polyps with a depressed surface: a rare form of sessile serrated adenoma/polyp.

Sessile serrated adenoma/polyps (SSA/Ps) usually appear flat to sessile with a smooth-appearing surface. However, macroscopic appearances of SSA/P can vary from flat-elevated to nodular and can even show a pedunculated configuration as we previously reported. The aim of the current study was to evaluate the clinicopathologic features of another under-recognized form of SSA/P which shows a depressed surface. Among 634 cases of sessile serrated adenoma/polyp, a total of seven sessile serrated adenoma/polyps showing a depressed surface were identified in 6 patients during the review of endoscopic images between January 2013 and November 2013. One of these was found during the review of previous endoscopic images of the same patient. Patients were more often middle-aged to elderly men (83.3%) and had synchronous conventional adenomas and/or SSA/Ps except for one man. The polyps usually occurred in the proximal colon (71.4%) and the mean size of polyps was 9.3 mm (range; 6-13 mm). Most cases (71.4%) were of a flat-elevated type, and the remaining polyps (28.6%) were sessile. The majority of polyps (85.7%) showed a mucus cap. All but one of the cases (85.7%) showed BRAF-V600E mutations. Our findings are that SSA/Ps can show a central depression although such cases are rare. The endoscopic and clinicopathologic features of SSA/Ps showing a depressed surface appear to be similar to usual SSA/Ps except for the presence of a depressed surface and marked male preponderance. Virtual slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1562070886167874 .

The significance of ectopic crypt formation in the differential diagnosis of colorectal polyps.

BACKGROUND: Ectopic crypts, defined as abnormally positioned crypts that have lost their orientation toward the muscularis mucosae, have been suggested to be the best defining histologic feature of traditional serrated adenoma (TSA). However, the significance of ectopic crypt formation (ECF) in the distinction between TSA and conventional adenoma (CA) has rarely been studied. METHODS: We designed this study to determine if ECF can be found in CA and its presence is exclusive to TSA. We studied 107 TSAs and 191 CAs including 106 tubular adenomas (TAs), 66 tubulovillous adenomas (TVAs), and 19 villous adenomas (VAs). RESULTS: ECF was identified in most (79.4%) but not all TSAs. Additionally, ECF was not infrequent in CA (62 of 191, 32.5%), and its presence correlated with the presence of a villous component and larger tumor size (each p <0.001). CONCLUSIONS: Based on its strong association with the presence of a villous component and larger tumor size, ECF appears to be involved in the protuberant growth of colorectal CA. Because ECF can be found in CA, particularly in cases with a villous component, the possibility of CA should be considered before making a diagnosis of TSA when encountering colorectal polyps with ECF. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_212.

Traditional serrated adenoma of the colorectum: clinicopathologic implications and endoscopic findings of the precursor lesions.

OBJECTIVES: To investigate the clinicopathologic and endoscopic features of precursor lesions associated with traditional serrated adenomas (TSAs). METHODS: Mutation studies for BRAF, KRAS, PIK3CA, and EGFR and immunohistochemical staining for Ki-67 were performed on 107 TSAs from 104 patients. RESULTS: Nondysplastic hyperplastic polyp (HP) or sessile serrated adenoma/polyp (SSA/P) precursor lesions were found in 56 (52.3%) TSAs, among which 32 (57.1%) cases showed a flat-elevated lesion with a type II pit pattern during endoscopy. TSAs with an SSA/P precursor lesion were usually found in the proximal colon, while TSAs with an HP or with no precursor lesion were mainly located in the distal colon and rectum (P < .001). TSAs with a precursor lesion showed a lower frequency of conventional epithelial dysplasia and KRAS mutation as well as a higher frequency of BRAF mutation compared with those with no precursor lesion (P = .002, P < .001, and P < .001, respectively). CONCLUSIONS: A significant proportion of HP or SSA/P precursor lesions accompanied by TSAs can be detected by endoscopy based on both their flat-elevated growth and type II pit patterns. The heterogeneity of TSAs in terms of clinicopathologic and molecular features correlated with the status or type of precursor lesions.

Solitary myofibroma of the sigmoid colon: case report and review of the literature.

A 58-year-old woman presented with a solitary myofibroma that arose in the sigmoid colon. Computed tomography revealed a highly enhanced intramural mass (1.3-cm maximum diameter) in the proximal sigmoid colon. Histologically, the tumor exhibited a biphasic growth pattern, which comprised haphazardly arranged, interwoven fascicles of plump, myoid-appearing spindle cells with elongated nuclei and abundant eosinophilic cytoplasm, and more cellular areas of primitive-appearing polygonal cells that were arranged in a hemangiopericytomatous pattern. The tumor cells were positive for smooth muscle actin (SMA), and negative for desmin, h-caldesmon, CD34, cytokeratin, S100 protein, and CD117. The Ki-67 labeling index was not high (up to 7%). Based on these histologic and immunohistochemical features, our patient was diagnosed with a myofibroma of the sigmoid colon. The presence of solitary myofibroma in the intestine of an adult requires attention to avoid misdiagnosis as a more aggressive mesenchymal tumor. VIRTUAL SLIDES: The virtual silde(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2096403796957687.

Endoscopic submucosal dissection for nonpedunculated submucosal invasive colorectal cancer: is it feasible?

BACKGROUND/AIMS: There have been no definite indications for additional surgical resection after endoscopic submucosal dissection (ESD) of submucosal invasive colorectal cancer (SICC). The aims of this study were to evaluate the feasibility of ESD for nonpedunculated SICC and to determine the need for subsequent surgery after ESD. PATIENTS AND METHODS: A total of 150 patients with nonpedunculated SICC in resected specimens after ESD were analyzed. Among them, 75 patients underwent subsequent surgery after ESD. Clinical outcomes of ESD and histopathological risk factors for lymph node (LN) metastasis were evaluated. RESULTS: The en-bloc resection and complete resection (R0) rates of ESD were 98% (147/150) and 95.3% (143/150), respectively. None of the patients had delayed bleeding after ESD. Perforations occurred in seven patients (4.7%), which were successfully treated by endoscopic clipping. After subsequent surgery for 75 patients, LN metastases were found in 10 cases (13.3%). The incidence of LN metastasis was significantly higher in tumors featuring submucosal invasion of at least 1500 µm, lymphovascular invasion, and tumor budding. Multivariate analysis showed that lymphovascular invasion (P=0.034) and tumor budding (P=0.015) were significantly associated with LN metastasis. Among the 150 patients, no local recurrence or distant metastasis was detected, except one patient with risk factors and who refused subsequent surgery, during the overall median follow-up of 34 months (range, 5-63 months). CONCLUSION: ESD is feasible and may be considered as an alternative treatment option for carefully selected cases of nonpedunculated SICC, provided that the appropriate histopathological curative criteria are fulfilled in completely resectable ESD specimens.

Pedunculated serrated polyp with histologic features of sessile serrated adenoma: a clinicopathologic and molecular study.

In this study, we describe a previously undescribed pedunculated serrated polyp of the colon showing typical features of sessile serrated adenoma/polyp (SSA/P). All polyps were pedunculated, located in the proximal colon, small in size, and occurred in elderly patients. Histologically, the polyps showed typical features of SSA/P in the basal crypts with irregular, asymmetric expression of Ki-67. All polyps showed the BRAF-V600E mutation. The cells in the polyps did not show obvious cytologic dysplasia, prominent serration, or diffuse cytoplasmic eosinophilia with any occurrence of the so-called "ectopic crypt formation." We consider pedunculated serrated polyp showing features of SSA/P as a previously undescribed form of serrated adenoma/polyp in the spectrum of serrated neoplasia, which might represent a pedunculated variant of SSA/P or a precursor lesion of proximally located traditional serrated adenomas in the earliest stage.

Rectal neuroendocrine and L-cell tumors: diagnostic dilemma and therapeutic strategy.

Rectal neuroendocrine tumors (NETs) are currently divided into L-cell and non-L-cell types. In the World Health Organization 2010 classification, L-cell tumors are defined as borderline, whereas non-L-cell tumors are considered to represent malignancies. To establish differential diagnostic criteria and therapeutic strategy, we investigated the pathologic features of rectal NETs associated with lymph node metastasis and the clinicopathologic significance of the L-cell phenotype. We analyzed 284 patients with rectal NETs. Factors, including T stage, mitosis, histologic pattern, lymphatic invasion, tumor border, and lymph node metastasis, were retrospectively evaluated. We also evaluated tumor immunoreactivity for L-cell markers, including glucagon-like peptide 1, pancreatic peptide, and peptide YY, in 240 cases. L-cell immunoreactivity was detected in 189 of 240 NETs (79%). Of the factors evaluated, only age and the frequency of lymphatic invasion were significantly different between patients with L-cell and non-L-cell tumors. Of the 284 patients, 18 (6.3%) had lymph node metastases. Lymphatic invasion and T stage were independent risk factors for lymph node metastasis. Subgroup analysis based on tumor size showed lymph node metastasis in 0%, 4%, 24%, and 100% of patients with NETs with a size of <5, 5 to 9, 10 to 14, and ≥ 15 mm, respectively. Depth of tumor invasion, lymphatic invasion, and mitosis were correlated with tumor size (P<0.0001). In conclusion, L-cell phenotype alone does not guarantee favorable biological characteristics. The clinical management of rectal NETs should depend on tumor size. Careful pathologic examination of lymphatic invasion is necessary.

Can endoscopic submucosal dissection technique be an alternative treatment option for a difficult giant (≥ 30 mm) pedunculated colorectal polyp?

BACKGROUND: Snare polypectomy of a giant pedunculated colorectal polyp is sometimes technically demanding, and, therefore, piecemeal resection is inevitable, despite the relative risk of invasive cancer and postpolypectomy bleeding. OBJECTIVE: The aim of this study was to evaluate the efficacy and safety of endoscopic submucosal dissection in comparison with conventional snare polypectomy for giant pedunculated polyps DESIGN AND SETTINGS: We retrospectively reviewed the clinical outcomes and complications of endoscopic polypectomy for giant pedunculated polyps from October 2006 to November 2011. PATIENTS: All the patients who underwent endoscopic submucosal dissection (n = 23) or snare polypectomy (n = 20) for pedunculated polyps ≥ 3 cm were enrolled consecutively. In the case of a giant pedunculated polyp with 1) poor visualization of the stalk, 2) technical difficulties in snare positioning for en bloc resection, or 3) need for trimming of the head, we did not attempt piecemeal snare polypectomy, and we performed endoscopic submucosal dissection instead. (These were arbitrarily defined as "difficult" giant pedunculated polyps.) MAIN OUTCOME MEASURES: Data on the patient's demography, endoscopic and histopathologic findings, clinical outcomes, and complications were analyzed. RESULTS: Among the 43 giant pedunculated polyps, 23 polyps were defined as "difficult" polyps and were removed with endoscopic submucosal dissection. Subpedunculated (stalk <1 cm) type was more common in the "difficult" polyp group (p = 0.01). The overall incidence of cancer was 18.6% (8/43). En bloc resection rates were 100% (23/23) in the endoscopic submucosal dissection group and 90% (18/20) in the snare polypectomy group. The procedure times of snare polypectomy and endoscopic submucosal dissection group did not differ significantly (41.7 ± 13.7 minutes vs 44.9 ± 35.6 minutes, p = 0.70). Postpolypectomy bleeding was noted in 1 case (4.3%) in the endoscopic submucosal dissection group and in 3 cases (15%) in the snare polypectomy group. CONCLUSIONS: Endoscopic submucosal dissection, as well as the snare polypectomy for giant pedunculated polyps, appeared to be effective without major complications and can be an alternative option to achieve en bloc resection, particularly for difficult cases, such as giant subpedunculated polyps.

Endoscopic submucosal dissection for colorectal tumors--1,000 colorectal ESD cases: one specialized institute's experiences.

PURPOSE: Endoscopic submucosal dissection (ESD) is a very useful endoscopic technique, making it possible to perform en bloc resection regardless of lesion size. Since the introduction of ESD at our hospital, we have performed 1,000 colorectal ESDs during 56 months. The purpose of this study was to evaluate the clinical outcomes of our colorectal ESD experience and to access the efficacy and safety of colorectal ESD. METHODS: Between October 2006 and August 2011, we performed ESD on 1,000 consecutive colorectal tumors in 966 patients. We evaluated the clinical outcomes of all said cases. RESULTS: The mean resected tumor size was 24.1 ± 13.3 (3-145) mm. Our overall endoscopic en bloc resection rate was 97.5% (975/1,000), and our R0 resection rate was 91.2% (912/1,000) respectively. Our perforation rate was 5.3% (53/1,000). Of these 53 perforations, 50 cases were treated through conservative management with/without endoscopic clipping, whereas the remaining 3 patients received laparoscopic operation. Pathological examination showed adenocarcinoma in 37.2% of cases (372/1,000) and neuroendocrine tumors in 11.2% (112/1,000). We recommended additional radical surgery to 82 patients who had a risk of lymph node metastasis. Follow-up colonoscopies were performed on 722 patients. During the median follow-up period of 13 (1-62) months, there were three recurrences (0.4%). CONCLUSIONS: ESD is technically difficult, with a substantial risk of perforation. However, ESD enabled en bloc resection and pathologically complete resection of large colorectal epithelial tumors and submucosal tumors. As experience with the technique increases, ESD may gradually replace piecemeal endoscopic mucosal resection and radical colon resection in the treatment of colorectal tumors.