Outcome of endoscopic submucosal dissection for colorectal tumors accompanied by fibrosis.

OBJECTIVE: Colorectal endoscopic submucosal dissection (ESD) is a difficult procedure. We aimed to retrospectively assess the relationship between the outcome of ESD for colorectal tumors and the degree of fibrosis. PATIENTS AND METHODS: We examined 203 consecutive patients with colorectal tumors larger than 20 mm in diameter who had undergone ESD at our hospital from November 2002 to June 2009. During ESD, the degree of submucosal fibrosis was classified into three types (F0-2). The relationship between the degree of fibrosis and the lesion characteristics and those between the outcome of ESD and the degree of fibrosis were analyzed. RESULTS: In the cases of granular laterally spreading tumors, the incidence of F2 fibrosis in nodular mixed-type tumors was significantly higher than that in homogenous-type tumors. An increase in the experience of the operators caused significant improvements in the rates of complete en bloc resection (p = 0.022) and perforation (p = 0.03) in the cases of lesions with F0-1 fibrosis. By contrast, operator experience did not cause any significant improvements in the rates of complete en bloc resection and perforation in the cases of lesions with F2 fibrosis. CONCLUSIONS: Experienced operators could safely perform complete en bloc resection in the cases of lesions with F0-1 fibrosis. However, in the cases of lesions with F2 fibrosis, the rate of complete en bloc resection was low and the perforation rate was high even when ESD was performed by an experienced operator.

Characterization of colorectal tumors using narrow-band imaging magnification: combined diagnosis with both pit pattern and microvessel features.

OBJECTIVE: We aimed to clarify the clinical usefulness of narrow-band imaging (NBI) magnification for evaluating both pit appearances and microvessel architecture in comparison with evaluation of microvessel architecture alone in invasion depth of colorectal tumors. MATERIAL AND METHODS: A total of 189 colorectal lesions [37 adenomas, 73 intramucosal to scanty submucosal invasive carcinomas and 79 massive submucosal invasive (SM-m) carcinomas] were analyzed. All lesions showing irregular pit structure were observed by NBI magnifying endoscopy. Based on both pit appearance and microvessel features, lesions were classified into three grades (C1, C2, C3), as described previously. Also, lesions were classified as high or low by microvessel irregularity. Furthermore, the histopathological background and the inter- and intraobserver variability of C subtype were assessed. RESULTS: The SM-m rate of C1, C2 and C3 was 5.2, 60.5 and 92.7%, respectively. On the other hand, SM-m rate of lesion with mildly and highly irregular vessels was 13.3 and 55.0%, respectively. For the histopathological background, a high percentage of destruction of the glandular orifice, disappearance of the lamina muscularis mucosae and superficial exposure of desmoplastic reaction (DR) were observed in type C3. For C subtype classification of NBI magnification findings, the kappa value for interobserver variability was 0.749, and the kappa value for intraobserver variability was 0.745. CONCLUSIONS: NBI magnification findings evaluated by both pit appearances and microvessel features (C subtype) showing a good kappa value in variability are more useful in invasion depth diagnosis of colorectal tumor than those evaluated by microvessel features alone.

Therapeutic strategy for colorectal laterally spreading tumor.

Most colorectal tumors larger than 20 mm in diameter are called laterally spreading tumors (LST), most of which are adenomatous lesions. Laterally spreading tumors are classified into two types according to their morphology, granular type (LST-G) and non-granular type (LST-NG). Each type has two subtypes. The former consists of a 'homogenous type' and a 'nodular mixed type', while the latter consists of a 'flat elevated (FE) type' and a 'psedodepressed (PD) type'. In LST-G and LST-NG FE types, type V pit pattern with magnification enables the recognition of the carcinomatous or submucosal invasive area. Most of these adenomatous large lesions can be cured by scheduled endoscopic piecemeal mucosal resection (EPMR). However, LST-G with large whole nodular type or type V pit pattern, which cannot be resected en bloc with a snare, is an indication for endoscopic submucosal dissection (ESD). The LST-NG PD has a high frequency of submucosal invasion and the submucosal invasive area cannot be recognized correctly in the pseudodepression with magnification prior to endoscopic treatment. Therefore, en bloc resection with ESD should be applied to LST-NG PD. The therapeutic strategy for choosing between EPMR and ESD for large LST lesions should therefore be determined based on the macroscopic findings of their subtype and pit pattern findings.

Magnifying colonoscopy used to predict disease relapse in patients with quiescent ulcerative colitis.

BACKGROUND: Many patients with quiescent ulcerative colitis (UC) experience relapse. However, clinical and conventional colonoscopic signs are inadequate for predicting relapse. This study's aim was to investigate the effectiveness of magnifying colonoscopy in predicting relapse in patients with quiescent UC and to evaluate the association of the findings of magnifying colonoscopy with the histological findings. METHODS: Magnifying colonoscopy was performed in 57 patients with clinical and endoscopic inactive UC. Patients were divided into 3 groups according to the findings of magnifying colonoscopy as MR (magnify-regular), MI (magnify-irregular), and MD (magnify-defect). Their subsequent clinical course was compared to assess the clinical usefulness of magnifying observation in predicting relapse. We also compared histological findings according to Riley's criteria to each finding of magnifying colonoscopy. RESULTS: Within 12 months, 1 of 18 patients (6.7%), 10 of 22 patients (45.5%), and 12 of 17 patients (70.6%) with findings of magnifying colonoscopy of MR, MI, and MD, respectively, experienced relapse. The MR group had a significantly low relapse rate compared with the MD and MI groups (P = 0.016, P = 0.002). When histological findings were compared with the findings of magnifying colonoscopy, the mean score of each variable, such as acute inflammatory cell infiltrate, chronic inflammatory cell infiltrate, and crypt architectural irregularities was significantly lower in the MR group than in the MD and MI groups. CONCLUSIONS: The findings of magnifying colonoscopy in patients with quiescent UC is useful for predicting relapse and is associated with histological grade of inflammation.