Hiroyuki Kanao

Narrow-band imaging magnification predicts the histology and invasion depth of colorectal tumors

BACKGROUND There are several reports concerning the differential diagnosis of non-neoplastic and neoplastic colorectal lesions by narrow-band imaging (NBI). However, there are only a few NBI articles that assessed invasion depth. OBJECTIVE To determine the clinical usefulness of NBI magnification for evaluating microvessel architecture in relation to pit appearances and in the qualitative diagnosis of colorectal tumors. DESIGN A retrospective study. SETTING Department of Endoscopy, Hiroshima University, Hiroshima, Japan. PATIENTS AND MAIN OUTCOME MEASUREMENTS A total of 289 colorectal lesions were analyzed: 12 hyperplasias (HP), 165 tubular adenomas (TA), 65 carcinomas with intramucosal to scanty submucosal invasion (M-SM-s), and 47 carcinomas with massive submucosal invasion (SM-m). Lesions were observed by NBI magnifying endoscopy and were classified according to microvessel features and pit appearances: type A, type B, and type C. Type C was divided into 3 subtypes (C1, C2, and C3), according to the detailed NBI magnifying findings of pit visibility, vessel diameter, irregularity, and distribution. These were compared with histologic findings. RESULTS Histologic findings of HP and TA were seen in 80.0% and 20.0%, respectively, of type A lesions. TA and M-SM-s were found in 79.7% and 20.3%, respectively, of type B lesions. TA, M-SM-s, and SM-m were found in 21.6%, 29.9%, and 48.5, respectively, of type C lesions. HPs were observed significantly more often than TAs in type A lesions, TAs were observed significantly more often than carcinomas in type B lesions, carcinomas were observed significantly more often than TAs in type C (P < .01). TA, M-SM-s, and SM-m were found in 46.7%, 42.2%, and 11.1% of type C1 lesions, respectively. M-SM-s and SM-m were found in 45.5% and 54.5%, respectively, of type C2 lesions. SM-m was found in 100% of type C3 lesions. TAs and M-SM-s were observed significantly more often than SM-m in type C1 lesions, and SM-m were observed significantly more often than TAs and M-SM-s in type C3 lesions (P < .01). CONCLUSIONS NBI magnification findings of colorectal lesions were associated with histologic grade and invasion depth.

Clinical outcomes of endoscopic submucosal dissection and endoscopic mucosal resection for laterally spreading tumors larger than 20 mm.

Background and Aims:  Colorectal laterally spreading tumors (LST) > 20 mm are usually treated by endoscopic submucosal dissection (ESD) or endoscopic mucosal resection (EMR). Endoscopic piecemeal mucosal resection (EPMR) is sometimes required. The aim of our study was to compare the outcomes of ESD and EMR, including EPMR, for such LST.

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

Abstract 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.

Management of T1 colorectal carcinoma with special reference to criteria for curative endoscopic resection

Background and Aim:  In guidelines 2010 for the treatment of colorectal cancer from the Japanese Society for Cancer of the Colon and Rectum (JSCCR), the criteria for identifying curable T1 colorectal carcinoma after endoscopic resection were well/moderately differentiated or papillary histologic grade, no vascular invasion, submucosal invasion depth less than 1000 µm and budding grade 1 (low grade). We aimed to expand these criteria.

CURRENT STATUS AND FUTURE PERSPECTIVES OF ENDOSCOPIC SUBMUCOSAL DISSECTION FOR COLORECTAL TUMORS

Endoscopic submucosal dissection (ESD) allows for en bloc tumor resection irrespective of the size of the lesion. In Japan, ESD has been established as a standard method for endoscopic ablation of malignant tumors in the upper gastrointestinal tract. Although the use of colorectal ESD has been gradually spreading with the development of numerous devices, ESD has not yet been fully established as a standard therapeutic method for colorectal lesions. Currently, colorectal ESD is performed as an ‘advanced medical treatment’ without national health insurance coverage. With the recent accumulation of numerous cases, the safety and simplicity of colorectal ESD have improved remarkably. Currently in Japan, a prospective multicenter cohort study organized by the Japan Gastroenterological Endoscopy Society is ongoing to clarify the safety and efficacy of colorectal ESD to obtain remuneration from national health insurance. In this report, we showed the outcome regarding safety and efficacy of colorectal ESD through a review of the published work. Of 2719 cases with colorectal ESD at 13 institutions, the complete en bloc resection and perforation rates were 82.8% (61–98.2%, 2082/2516) and 4.7% (1.4–8.2%, 127/2719), respectively. Additional surgery for perforation was very rare because perforations were tiny enough to be closed endoscopically by clips in most of the cases and treated conservatively. In the near future, colorectal ESD will be a common therapeutic method for early colorectal carcinoma.

CURRENT STATUS IN THE OCCURRENCE OF POSTOPERATIVE BLEEDING, PERFORATION AND RESIDUAL/LOCAL RECURRENCE DURING COLONOSCOPIC TREATMENT IN JAPAN

Bleeding, perforation, and residual/local recurrence are the main complications associated with colonoscopic treatment of colorectal tumor. However, current status regarding the average incidence of these complications in Japan is not available. We conducted a questionnaire survey, prepared by the Colorectal Endoscopic Resection Standardization Implementation Working Group, Japanese Society for Cancer of the Colon and Rectum (JSCCR), to clarify the incidence of postoperative bleeding, perforation, and residual/local recurrence associated with colonoscopic treatment. The total incidence of postoperative bleeding was 1.2% and the incidence was 0.26% with hot biopsy, 1.3% with polypectomy, 1.4% with endoscopic mucosal resection (EMR), and 1.7% with endoscopic submucosal dissection (ESD). The total incidence of perforation was 0.74% (0.01% with the hot biopsy, 0.17% with polypectomy, 0.91% with EMR, and 3.3% with ESD). The total incidence of residual/local recurrence was 0.73% (0.007% with hot biopsy, 0.34% with polypectomy, 1.4% with EMR, and 2.3% with ESD). Colonoscopic examination was used as a surveillance method for detecting residual/local recurrence in all hospitals. The surveillance period differed among the hospitals; however, most of the hospitals reported a surveillance period of 3–6 months with mainly transabdominal ultrasonography and computed tomography in combination with the colonoscopic examination.

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.

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

Abstract 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.

MID-TERM PROGNOSIS AFTER ENDOSCOPIC RESECTION FOR SUBMUCOSAL COLORECTAL CARCINOMA: SUMMARY OF A MULTICENTER QUESTIONNAIRE SURVEY CONDUCTED BY THE COLORECTAL ENDOSCOPIC RESECTION STANDARDIZATION IMPLEMENTATION WORKING GROUP IN JAPANESE SOCIETY FOR CANCER OF THE COLON AND RECTUM

We carried out a retrospective questionnaire survey of 792 submucosal colorectal carcinoma (CRC) cases from 15 institutions affiliated with the Colorectal Endoscopic Resection Standardization Implementation Working Group in Japanese Society for Cancer of the Colon and Rectum. In these cases, endoscopic resection (ER) and surveillance was carried out without additional surgical resection. Local recurrence or metastasis was observed in 18 cases. Local submucosal recurrence was observed in 11 cases, and metastatic recurrence was observed in 13 cases. Among the 15 cases in which the depth of submucosal invasion was measured, two cases showed depth less than 1000 µm, which has other risk factors for metastasis. Metastatic recurrence was observed in the lung, liver, lymph node, bone, adrenal glands, and the brain; in some cases, metastatic recurrence was observed in multiple organs. Death due to primary disease was observed in six cases. The average interval between ER and recurrence was 19.7 ± 9.2 months. In 16 cases, recurrence was observed within 3 years after ER. Thus, validity of ER without additional surgical resection for cases with the conditions that the depth of submucosal invasion is less than 1000 µm and the histological grade is well or moderately differentiated adenocarcinoma with no lymphatic and venous involvement was proven.

USEFULNESS AND SAFETY OF SB KNIFE JR IN ENDOSCOPIC SUBMUCOSAL DISSECTION FOR COLORECTAL TUMORS

Use of a Dual knife has become commonplace for endoscopic submucosal dissection (ESD) of colorectal tumors at Hiroshima University Hosipital. A Hook knife has been also used in combination with the Dual knife, depending on the location of the lesion. We have had recent opportunities to use a scissors‐type SB knife Jr. We retrospectively compared outcomes of colorectal ESD performed with the Dual knife in combination with the SB knife Jr versus the Hook knife. In conclusion, although the Hook knife was shown to be a very useful auxiliary device for colorectal ESD, the SB knife Jr. yielded better results than the Hook knife in terms of complete en block resection and avoidance of perforation. Use of the Dual knife with the SB Knife Jr shows good potential for improving complete en bloc resection rate and safety of technically difficult colorectal ESD.