Efficacy of a Gastroscope for Cecal Intubation during Colonoscopy in Patients with Severe Sigmoid Adhesion.

BACKGROUND: Cecal intubation during colonoscopy is difficult to achieve in patients with severe sigmoid adhesions. This retrospective observational study assessed the efficacy of using a gastroscope for colonoscopy in patients with severe sigmoid adhesions. Furthermore, the ability of computed tomography (CT) to predict the possibility of cecal intubation using a gastroscope was examined. METHODS: A total of 1,626 patients who underwent colonoscopy for total colon observation by one endoscopist were enrolled. Cecal intubation rate and other procedure-related outcomes were evaluated. We also investigated whether identification of the sigmoid colon pathway by CT was involved in cecal intubation rate using a gastroscope. RESULTS: Of the enrolled patients, cecal intubation by colonoscope was not feasible in 19 patients (1.2%) because of severe sigmoid adhesions. Cecal intubation was possible in 13 patients (68.4%) using a gastroscope, and the cecal intubation rate of peritoneal carcinomatosis (0%, p < 0.01) was significantly lower than that of other causes such as a diverticulum (100%) and history of gynecologic surgery (80%). The identifiable case of the sigmoid colon pathway by horizontal section on CT showed significantly higher cecal intubation rate compared to those of unidentifiable cases (92.3% vs. 16.7%, p < 0.01). CONCLUSION: Using a gastroscope is effective in performing cecal intubation during colonoscopy in patients with severe sigmoid adhesions. However, in patients with sigmoid adhesions caused by peritoneal carcinomatosis, cecal intubation may be difficult, even when a gastroscope is used. The ability of CT to identify the sigmoid colon pathway may predict success of cecal intubation.

Skeletal Muscle Depletion: A Risk Factor for Pneumonia following Gastric Endoscopic Submucosal Dissection in Elderly Patients.

INTRODUCTION: Endoscopic submucosal dissection (ESD) is an effective treatment for gastric neoplasms in elderly patients; however, it involves several adverse events, including pneumonia. This study aimed to investigate whether skeletal muscle depletion (SMD) was associated with the development of pneumonia in elderly patients who underwent gastric ESD. METHODS: This retrospective observational cohort study included 157 patients (≥80 years) who had undergone gastric ESD. The skeletal muscle cross-sectional area was measured by CT, and the value of the third lumbar vertebra skeletal muscle index (L3 SMI) was evaluated. The SMD was defined as an L3 SMI value ≤38.0 cm2/m2 for women and ≤42.0 cm2/m2 for men. Pneumonia was also diagnosed using CT to identify all included patients. RESULTS: Among 157 patients, 66 (42.0%) showed SMD. In the SMD group, the incidence of pneumonia was 21.2%, whereas it was 7.7% in the non-SMD group (p = 0.018). The longest hospitalization duration was 19 days. Antibiotics were administered in 61.9% of the patients. Procedure time was not significantly different between the groups (72 ± 54 min vs. 62 ± 44 min, p = 0.201). On multivariate analysis, SMD was an independent risk factor for the development of pneumonia (odds ratio = 3.16, 95% confidence interval, 1.18-8.50, p = 0.023). CONCLUSIONS: SMD was not a rare entity in patients aged ≥80 years with gastric neoplasms. SMD was a significant risk factor for pneumonia related to gastric ESD in elderly patients.

Long-term outcomes after endoscopic submucosal dissection for differentiated-type early gastric cancer that fulfilled expanded indication criteria: A prospective cohort study.

BACKGROUND AND AIM: Endoscopic resection for early gastric cancer (EGC) is widely performed. However, there is still a paucity of strong evidence regarding long-term outcomes after endoscopic submucosal dissection (ESD) for the expanded indication criteria of the Japanese guidelines (ver. 2010). METHODS: Endoscopic submucosal dissection was performed in patients with EGC that met the expanded indication criteria: (i) cT1a, differentiated-type EGC of 2 to 5 cm, ulcer negative or (ii) cT1a, differentiated-type EGC of ≤3 cm, ulcer positive. Patients whose pathological examination fulfilled the curative resection criteria were then enrolled in this cohort study: negative vertical margin, negative lymphovascular invasion, and (i) pT1a, differentiated-type, and ulcer negative; (ii) pT1a, differentiated-type, ≤3 cm, and ulcer positive; or (iii) pT1b1 (<500-µm submucosal invasion), differentiated-type, and ≤3 cm. Patients with only a positive horizontal margin as a noncurative factor were included for follow-up. RESULTS: From September 2003 to February 2012, a total of 356 patients underwent ESD, and 214 were enrolled in the survival analysis. One hundred twenty patients (56%) had >2 cm in diameter and ulcer-negative lesions, and 94 (44%) had ≤3 cm and ulcer-positive lesions. The vital status at 5 years after ESD was confirmed in all (100%) patients. No local or metastatic recurrence was detected; however, 26 metachronous gastric cancers developed, and 1 patient died of metachronous gastric cancer. The 5-year disease-specific and overall survival rates were 99.5% (95% confidence interval [CI], 97.2%-100%) and 93.9% (95% CI, 89.8%-96.4%), respectively. CONCLUSION: ESD for EGC that fulfills the expanded criteria is feasible and shows favorable long-term outcomes.

Narrow band imaging under less-air condition improves the visibility of superficial esophageal squamous cell carcinoma.

BACKGROUND: The current virtual chromoendoscopy equipment cannot completely detect superficial squamous cell carcinoma (SCC) in the esophagus, despite its development in the recent years. Thus, in this study, we aimed to elucidate the appropriate air volume during endoscopic observation to improve the visibility of esophageal SCC. METHODS: This retrospective study included a total of 101 flat type esophageal SCCs identified between April 2017 and January 2019 at the Department of Gastrointestinal Oncology, Osaka International Cancer Institute. Video images of narrow band imaging (NBI) under both less-air and standard-air conditions were recorded digitally. Videos were evaluated by five endoscopists. Relative visibility between less-air and standard-air conditions of the brownish area, brownish color change of the epithelium, and dilated intrapapillary capillary loop (IPCL) were graded as 5 (definitely better under less-air condition) to 1 (definitely worse under less-air condition), with 3 indicating average visibility (equivalent to standard-air observation). RESULTS: The mean (standard deviation) visibility score of the brownish area, brownish color change of the epithelium, and dilated IPCLs under less-air condition were 3.94 (0.58), 3.73 (0.57), and 4.13 (0.60), respectively, which were significantly better than that under standard-air condition (p < 0.0001). Esophageal SCC evaluated as ≥ 4 in the mean visibility score of the brownish area, brownish color change of the epithelium, and dilated IPCLs accounted for 50% (51/101 lesions), 34% (34/101 lesions), and 67% (68/101 lesions), respectively. CONCLUSIONS: The present results suggested that NBI with less air might improve the visibility of flat type esophageal SCC compared with NBI with standard air. Less-air NBI observation may facilitate the detection of flat type esophageal SCC. TRIAL REGISTRATION: The present study is a non-intervention trial.

Does cold snare polypectomy completely resect the mucosal layer? A prospective single-center observational trial.

BACKGROUND AND AIM: The true incidence of incomplete muscularis mucosa resection with cold snare polypectomy (CSP) is unknown. We examined the incidence of incomplete muscularis mucosa resection both with and without cold snare defect protrusion (CSDP). METHODS: We prospectively enrolled patients undergoing polypectomy for 4 to 9mm nonpedunculated polyps. We evaluated the presence of CSDP immediately following CSP and biopsied the CSDP or the center of the mucosal defect without CSDP. The presence of the muscularis mucosa and any residual polyp in the biopsies was evaluated histologically. The primary outcome was the incidence of incomplete mucosal layer resection defined as the presence of muscularis mucosa or residual polyp in the biopsies. RESULTS: From August 2017 to October 2018, 188 patients were screened, and 357 polyps were included. CSDP was detected in 122/355 (34%) evaluated mucosal defects. Excluding five lesions requiring hemostasis immediately following CSP, 352 mucosal defects were biopsied. After excluding 102 biopsies containing normal mucosa, we evaluated 250 biopsies. The overall incidence of incomplete mucosal layer resection was 63% (159/250), 76% (68/90) with CSDP and 57% (91/159) without CSDP (P < 0.01). Both univariate and multivariate analyses showed that size (≥ 6 mm), resection time (≥ 5 s), and serrated lesions were risk factors for CSDP. CONCLUSIONS: Cold snare defect protrusion (CSDP), which was present with 36%, was a good indicator for incomplete mucosal layer resection. Even in nonCSDP polypectomies, 57% of the mucosal layer was not removed completely. Thus, CSP should be used for intra-epithelial lesions only, and careful pretreatment evaluation is recommended.

Impact of age at diagnosis of head and neck cancer on incidence of metachronous cancer.

BACKGROUND: Metachronous cancer in patients with head and neck cancer (HNC) is common and is associated with a poor prognosis. We aimed to evaluate the incidence of metachronous cancer at different sites according to age at diagnosis of index HNC. METHODS: We collected data on 2011 patients with oral cancer, oropharynx cancer, hypopharyngeal cancer, and laryngeal cancer as index cancers using the Osaka International Cancer Institute Cancer Registry database between 2005 and 2016. Among these, we analyzed 1953 patients after excluding 5 patients who were not followed-up and 53 patients with simultaneous multiple index cancers. We evaluated the cumulative incidence of metachronous cancer in the esophagus, lung, and other sites according to age at diagnosis of the index HNC using the Kaplan-Meier method. Multivariate logistic regression analysis was performed to identify factors that influenced the incidence of metachronous cancers following HNC. RESULTS: The cumulative incidence of metachronous esophageal cancer in young patients (< 65 years) was significantly higher than that in old patients (≥ 65 years) (12.1% vs 8.5% at 5 years, and 16.5% vs 11.2% at 10 years; p = 0.015). On the other hand, the cumulative incidence of the other cancers in young patients was significantly lower than that in old patients (7.8% vs 12.2% at 5 years, and 13.9% vs 15.3% at 10 years; p = 0.017). The cumulative incidence of lung cancer was not significance according to age at diagnosis of the index HNC. In the multivariate analysis, histological type (squamous cell carcinoma) and lesion location (hypopharynx and larynx) were independently associated with metachronous cancers. Moreover, age at diagnosis of the index HNC (< 65 years), histological type (squamous cell carcinoma) and lesion location (hypopharynx) were significant predictors of metachronous esophageal cancer incidence and lesion location (hypopharynx) was a significant predictor of metachronous lung cancer incidence. CONCLUSION: Risk stratification of metachronous cancers with age and other predictors may help to properly manage patients with HNC. TRIAL REGISTRATION: The present study is a non-intervention trial.

Efficacy of autofluorescence imaging for flat neoplasm detection: a multicenter randomized controlled trial (A-FLAT trial).

BACKGROUND AND AIMS: Colorectal flat (nonpolypoid) lesions can be overlooked during colonoscopy. This study evaluated the efficacy of updated autofluorescence imaging (AFI) for detecting colorectal flat neoplasms. METHODS: This was a prospective, multicenter, randomized controlled trial in 9 Japanese tertiary institutions. Patients undergoing colonoscopy because of positive fecal immunochemical tests, surveillance after polypectomy, or investigation of minor symptoms were enrolled and randomly assigned to either the white-light imaging (WLI) or the AFI group. Primary outcome measurement was number of flat neoplasms per patient. RESULTS: From November 2015 to June 2017, 817 patients were enrolled. After excluding 15 patients, 802 were finally analyzed (404, WLI; 398, AFI). Patients' backgrounds (sex, age, indication of colonoscopy, experience of endoscopists) and quality of colonoscopy (bowel preparation, sedative use, cecal insertion rate, insertion and withdrawal time) were not different between groups. Number of flat neoplasms in each patient was significantly higher in the AFI than in the WLI group (.87 [95% confidence interval [CI], .78-.97] vs .53 [95% CI, .46-.61]), whereas overall and polypoid neoplasm detection was not significantly different between the groups (1.33 [95% CI, 1.22-1.45] vs 1.14 [95% CI, 1.03-1.24], .46 [95% CI, .40-.53] vs .60 [95% CI, .53-.68]). Flat neoplasms were more frequently detected in the right-sided colon with AFI (.61 [95% CI, .54-.70] vs .30 [95% CI, .25-.36]) but not in the left-sided colon and rectum (.26 [95% CI, .21-.32] vs .23 [95% CI, .19-.28]). CONCLUSIONS: Updated AFI improves the detection of flat colorectal neoplasms in the right-sided colon compared with WLI. (Clinical trial registration number: UMIN000019355.).

Differences in Clinical Course of Intraprocedural and Delayed Perforation Caused by Endoscopic Submucosal Dissection for Colorectal Neoplasms: A Retrospective Study.

BACKGROUND: Although the use of endoscopic submucosal dissection (ESD) as a minimally invasive treatment for large superficial colorectal neoplasms is increasing, colorectal ESD remains technically challenging. As perforation in the colorectum is generally considered to be associated with a higher risk of complications, the aim of this study was to investigate the characteristics of perforation caused by colorectal ESD. METHODS: This retrospective study included 635 lesions treated with colorectal ESD, between February 2011 and December 2015, in a tertiary cancer center. We evaluated and compared the clinical course and short-term outcomes of the intraprocedural perforation group with those of the delayed perforation and no perforation groups. RESULTS: Perforation occurred in 45 (7.1%) of the 635 cases. Thirty-six cases were intraprocedural perforation (5.7%), all of which were successfully closed with endoclips during the procedure. Nine cases of delayed perforation occurred (1.4%). No emergency surgery was performed in the intraprocedural perforation group; however, 5 of 9 cases underwent emergency surgery in the delayed perforation group (56%, p < 0.0001). There were statistically significant differences between the intraprocedural and delayed perforation groups with regard to the hospitalization period, fasting period, abdominal pain scale, peak white blood cell (WBC) count, and peak C-reactive protein (CRP), and between the intraprocedural and no perforation groups with regard to the location of the lesion, hospitalization period, fasting period, abdominal pain scale, peak WBC, peak CRP, and en bloc resection rate. CONCLUSIONS: While intraprocedural perforation due to colorectal ESD can be managed conservatively, delayed perforation can lead to serious adverse events.

Underwater endoscopic mucosal resection for superficial nonampullary duodenal adenomas.

BACKGROUND AND STUDY AIM: Underwater endoscopic mucosal resection (UEMR) was recently developed in a Western country. A prospective cohort study to investigate the effectiveness of UEMR was conducted in patients with small superficial nonampullary duodenal adenomas. PATIENTS AND METHODS: Patients with duodenal adenomas ≤ 20 mm were enrolled. After the duodenal lumen had been filled with physiological saline, UEMR was performed without submucosal injection. Endoclip closure was attempted for all mucosal defects after UEMR. Follow-up endoscopy with biopsy was performed 3 months later. The primary end point was the complete resection rate, defined as neither endoscopic nor histological residue of adenoma at the follow-up endoscopy. RESULTS: 30 patients with 31 lesions were enrolled. The mean (SD) tumor size was 12.0 mm (7.3). The complete resection rate was 97 % (90 % confidence interval, 87 % - 99 %). The en bloc resection rate was 87 %. All mucosal defects were successfully closed by endoclips. No adverse events occurred except for one case of mild aspiration pneumonia. CONCLUSIONS: UEMR is efficacious for the treatment of small duodenal adenomas, but further large-scale trials are warranted to confirm these results.

Safety of cold snare polypectomy for duodenal adenomas in familial adenomatous polyposis: a prospective exploratory study.

BACKGROUND: Cold snare polypectomy (CSP) to remove multiple duodenal adenomas (MDAs) in patients with familial adenomatous polyposis (FAP) could be an effective and less invasive method than more extensive surgery. The aim of the present study was to determine the safety of this procedure. METHODS: This prospective exploratory study included 10 consecutive patients with FAP and MDAs who underwent CSP for as many as 50 duodenal adenomas. The primary outcome was the incidence of severe adverse events. RESULTS: 10 patients were enrolled and underwent 332 CSPs from June 2016 to January 2017. The median procedure time was 33 minutes (range 25 - 53), and the median number of polyps removed during a single session was 35 (range 10 - 50). Most of the removed polyps were ≤ 10 mm. None of the 10 patients experienced a severe adverse event. One patient developed arterial bleeding during the procedure, but it was easily managed using hemoclips. CONCLUSIONS: CSP for MDAs in patients with FAP was safe. The long-term efficacy of this procedure should be investigated.

Comparison of ENDO CUT mode and FORCED COAG mode for the formation of stricture after esophageal endoscopic submucosal dissection in an in vivo porcine model.

BACKGROUND AND STUDY AIM: Stricture is a major complication of esophageal endoscopic submucosal dissection (ESD) for superficial esophageal carcinoma. To date, various methods have been developed to prevent stricture. However, the mechanism by which different electrosurgical unit (ESU) modes affect the formation of post-ESD stricture has not been evaluated. This study aimed to compare the degree of stricture caused by two major ESU modes (ENDO CUT mode and FORCED COAG mode) in a porcine model. METHODS: Twelve ESD procedures covering half of the circumference were performed in six pigs. Mucosal incision was performed with a ball-tip flush knife and submucosal dissection was performed with a hook knife; the two modes used were ENDO CUT I (Effect 2, Duration 2, Interval 3) and FORCED COAG mode (Effect 3, 40 W) (VIO300D, ERBE Germany). The pigs were killed humanely 30 days after ESD, and the severity of stricture and fibrosis was assessed. RESULTS: The resected site of the esophagus showed complete mucosal regrowth and scar formation in all pigs. There was no significant difference between the two modes in procedure time and size of resected specimen (14.4 ± 2.4 and 15.9 ± 6.1 min, P = 0.589; 626 ± 148, 661 ± 186 mm2, P = 0.74, respectively). Stricture rate and severity of fibrosis in the submucosal layer were significantly lower in ENDO CUT mode than in FORCED COAG mode (31.5 ± 16.0% vs 44.3 ± 11.6%, P = 0.046; 36.2 ± 17.1% vs 60.4 ± 26.8%, P = 0.024, respectively). CONCLUSIONS: ENDO CUT mode showed promising ability to attenuate fibrosis and stricture after esophageal ESD.

Transoral endoscopic examination of head and neck region.

Transoral endoscopy with narrow band imaging (NBI) is useful for early detection of head and neck (HN) cancer. However, the lateral and anterior walls of the oropharynx, postcricoid area, and posterior wall of the hypopharynx are difficult to observe using transoral endoscopy. Advanced cancers in these regions may be missed even when NBI is used. This report highlights a method of transoral endoscopic examination of the HN region. For observation of the oral cavity and oropharynx, it is important to observe these regions without using a mouthpiece. Wide opening of the mouth facilitates observation of the oral cavity and oropharynx. Moreover, visibility of the oropharynx, including the anterior wall, is dramatically improved, when the patient positions the tongue forward and says 'aaah.' This technique also facilitates observation of the dorsum of the tongue, which is difficult to observe from a tangential view when using a mouthpiece. To observe the hypopharynx, the Valsalva maneuver is very useful. Patient cooperation is important when observing the HN region thoroughly to gain clear endoscopic views. Narcotic drugs, such as pethidine hydrochloride, are ideal for conscious sedation and reduce the gag reflex while still allowing patient cooperation. From the oral cavity to the hypopharynx, including the lateral and anterior walls of the oropharynx, postcricoid area, and posterior wall of the hypopharynx, most of the HN region can be observed during routine examination using transoral endoscopy without any special devices.

Line-assisted complete closure for a large mucosal defect after colorectal endoscopic submucosal dissection decreased post-electrocoagulation syndrome.

BACKGROUND AND AIM: The incidence of post-endoscopic submucosal dissection (ESD) coagulation syndrome (PECS) can be decreased by closing mucosal defects. However, large mucosal defects after colorectal ESD cannot be closed endoscopically. We established line-assisted complete clip closure (LACC), a novel technique for large mucosal defects after colorectal ESD. We evaluated the prophylactic efficacy of LACC for preventing PECS. METHODS: Sixty-one consecutive patients on whom LACC after colorectal ESD was attempted from January 2016 to August 2016 were analyzed. After exclusion of patients with incomplete LACC and adverse events during ESD, 57 patients comprised the LACC group. In contrast, 495 patients who did not undergo closure of a mucosal defect comprised the control group. Propensity score matching was used to adjust for patients' backgrounds. Treatment outcomes were evaluated between the groups. RESULTS: Median resected specimen size in the LACC-attempted group was 35 mm (range, 20-72 mm), and LACC success rate was 95% (58/61). Median procedure time of LACC was 14 min. In the LACC group, incidence of PECS was only 2%, and no delayed bleeding or perforation occurred. Propensity score matching created 51 matched pairs. Adjusted comparisons between the LACC and control groups showed a lower incidence of PECS (0% vs 12%, respectively; P = 0.03) and shorter hospitalization (5 vs 6 days, respectively; P < 0.001) in the LACC group. CONCLUSION: This study suggests that LACC can effectively reduce the incidence of PECS, although further large-scale studies are warranted.

Endoscopic fenestration for benign complete anastomotic obstruction following rectal surgery.

Video 1Endoscopic fenestration for benign complete anastomotic obstruction after rectal surgery.

Olmesartan-associated sprue-like enteropathy diagnosed by capsule endoscopy and double balloon endoscopy.

Sprue-like enteropathy associated with olmesartan is characterized by villous atrophy in the duodenum. We report the case of an 81-year-old woman diagnosed with olmesartan-associated sprue-like enteropathy with no villous atrophy in the duodenum. The patient had been taking olmesartan for 10 years and complained of diarrhea and weight loss. Despite undergoing general treatment for 2 months, her symptoms showed no improvement. Gastrointestinal endoscopy and pathological findings showed no villous atrophy in the duodenum. However, villous atrophy was observed in the small intestine by capsule endoscopy. Pathological biopsy with double balloon endoscopy provided a definitive diagnosis. Diarrhea improved with the discontinuation of olmesartan and weight increased within a week of withdrawal. After the improvement of clinical symptoms, both endoscopic and pathological findings of villous atrophy in small intestine showed improvement.

Effects of antithrombotic drugs on the results of fecal immunochemical test in colorectal neoplasms screening.

Fecal immunochemical test (FIT) is widely used as a colorectal cancer screening tool. Antithrombotic drugs may affect the screening performance of FIT for colorectal tumors. The aim of this study was to clarify the effect of antithrombotic agents on FIT accuracy in screening for colorectal neoplasms. This retrospective study enrolled a total of 758 patients who underwent both FIT and total colonoscopy. The effect of antithrombotic drugs on FIT accuracy in detecting colorectal neoplasms (CN), including colorectal cancer (CRC), advanced adenoma (AA), and non-advanced adenoma (NAA), was examined. Of the 758 patients, 144 (19%) received antithrombotic drugs (administration group). In administration group, 61/144 (42%) cases had CN [CRC:14, AA:15, NAA:32] and 217/614 (35%) cases had CN (CRC:43, AA:56, NAA:118) in non-administration group. The prevalence of CN was not significantly different between the two groups (p = 0.1157). There was no significant difference in sensitivity or specificity of the detection of all types of CN with or without taking antithrombotic drugs. Neither the positive predictive value nor negative predictive value of FIT was affected by antithrombotic drug administration. Taking antithrombotic drugs may not have a large impact on sensitivity, specificity, positive predictive value, or negative predictive value of FIT in screening for CN.

High incidence of head and neck cancers after endoscopic resection for esophageal cancer in younger patients.

BACKGROUND: Second cancers in patients with esophageal cancer (EC) are common and have a poor prognosis. We evaluated the incidence of second cancers at different sites by patients' ages when their index ECs were diagnosed. METHODS: This study included patients who underwent endoscopic resection for superficial EC at our hospital between September 1994 and September 2011. Patients' data, including sex, age at diagnosis, sequence of cancer incidence, cancer histology, and cancer site, were extracted from the cancer registry. RESULTS: Of 544 patients, 255 developed second cancers. Simultaneous head and neck cancers (HNCs) and other organ cancers (OCs) were, respectively, present in 15% (80/544) and 9.6% (52/544) of patients; and 30% (162/544) developed metachronous second cancers over a median follow-up period of 79.5 months (range 2-120), including 44 metachronous HNCs and 70 OCs. The cumulative incidence of metachronous HNCs was significantly higher in younger patients (< 60 years) than in older patients (≥ 60 years; P = 0.001), whereas the cumulative incidence of OCs was significantly higher in older patients than in younger patients (P = 0.03). CONCLUSIONS: The incidence of second HNC after index EC was higher in younger-onset patients than in older-onset patients. We suggest that younger patients with EC should be carefully monitored for early detection of second HNC.

Natural history of early gastric cancer: series of 21 cases.

Background and study aims While knowledge of the natural history of early gastric cancer (EGC) may be useful in relevant clinical situations, few relevant reports are available. Therefore, we investigated the progression of EGC. We gathered data regarding 114 cases of EGC from 2005 to 2015 from a hospital cancer registry and analyzed 21 lesions that fulfilled five inclusion criteria. Deep progression was defined as submucosal invasion by a mucosal tumor and proper muscle invasion by a submucosal tumor. Lateral progression was defined as ≥ 20 % increase in size. During median follow-up of 23 months, one of 18 mucosal tumors showed deep progression and six showed lateral progression. Of three submucosal tumors, two showed deep progression and three showed lateral progression. Our study suggests that a certain proportion of mucosal cancers can lie dormant for several years. Further large-scale studies in a multicenter setting should overcome the limitations of this study.