Effective use of the Japan Narrow Band Imaging Expert Team classification based on diagnostic performance and confidence level

Five years have passed since the Japan Narrow Band Imaging Expert Team (JNET) classification was proposed in 2014. However, the diagnostic performance of this classification has not yet been established. We conducted a retrospective study and a systematic search of Medical Literature Analysis and Retrieval System On-Line. There were three retrospective single center studies about the diagnostic performance of this classification. In order to clarify this issue, we reviewed our study and three previous studies. This review revealed the diagnostic performance in regards to three important differentiations.(1) Neoplasia from non-neoplasia;(2) malignant neoplasia from benign neoplasia;and (3) deep submucosal invasive cancer (D-SMC) from other neoplasia. The sensitivity in differentiating neoplasia from non-neoplasia was 98.1%-99.8%. The specificity in differentiating malignant neoplasia from benign neoplasia was 84.7%-98.2% and the specificity in the differentiation D-SMC from other neoplasia was 99.8%-100.0%. This classification would enable endoscopists to identify almost all neoplasia, to appropriately determine whether to perform en bloc resection or not, and to avoid unnecessary surgery. This article is the first review about the diagnostic performance of the JNET classification. Previous reports about the diagnostic performance have all been retrospective single center studies. A large-scale prospective multicenter evaluation study is awaited for the validation.

Feasibility of single-incision laparoscopic cholecystectomy for acute cholecystitis

AIM: To assess the safety of single-incision laparoscopic cholecystectomy(SILC) for acute cholecystitis.METHODS: All patients who underwent SILC at Sano Hospital(Kobe, Japan) between January 2010 and December 2014 were included in this retrospective study. Clinical data related to patient characteristics and surgical outcomes were collected from medical records. The parameters for assessing the safety of the procedure included operative time, volume of blood loss, achievement of the critical view of safety, use of additional trocars, conversion to laparotomy, intraoperative and postoperative complications, and duration of postoperative hospital stay. Patient backgrounds were statistically compared between those with and without conversion to laparotomy.RESULTS: A total of 100 patients underwent SILC for acute cholecystitis during the period. Preoperative endoscopic treatment was performed for suspected choledocholithiasis in 41 patients(41%). The mean time from onset of acute cholecystitis was 7.7 d. According to the Updated Tokyo Guidelines(TG13) for the severity of cholecystitis, 86 and 14 patients had grade Ⅰ and grade Ⅱ acute cholecystitis, respectively. The mean operative time was 87.4 min. The mean estimated blood loss was 80.6 mL. The critical view of safety was obtained in 89 patients(89%). Conversion laparotomy was performed in 12 patients(12%). Postoperative complications of Clavien-Dindo grade Ⅲ or greater were observed in 4 patients(4%). The mean duration of postoperative hospital stay was 5.7 d. Patients converted from SILC to laparotomy tended to have higher days after onset.CONCLUSION: SILC is feasible for acute cholecystitis; in addition, early surgical intervention may reduce the risk of laparotomy conversion.

Post-colonoscopy colorectal cancer rate in the era of highdefinition colonoscopy

AIM To investigate the post-colonoscopy colorectal cancer(PCCRC) rate for high-definition(HD) colonoscopy compared with that for standard-definition colonoscopy reported previously.METHODS Using medical records at Sano Hospital(SH) and Dokkyo Medical University Koshigaya Hospital(DMUKH), we retrospectively obtained data on consecutive patients diagnosed as having CRC between January 2010 andDecember 2015. The definition of PCCRC was diagnosis of CRC between 7 and 36 mo after initial high-definition colonoscopy that had detected no cancer, and patients were divided into a PCCRC group and a non-PCCRC group. The primary outcome was the rate of PCCRC for HD colonoscopy. The secondary outcomes were factors associated with PCCRC and possible reason for occurrence of early and advanced PCCRC.RESULTS Among 892 CRC patients, 11 were diagnosed as having PCCRC and 881 had non-PCCRC. The PCCRC rate was 1.7%(8/471) at SH and 0.7%(3/421) at DMUKH. In comparison with the non-PCCRC group, the PCCRC group had a significantly higher preponderance of smaller tumors(39 mm vs 19 mm, P = 0.002), a shallower invasion depth(T1 rate, 25.4% vs 63.6%, P = 0.01), a non-polypoid macroscopic appearance(39.0% vs 85.7%, P = 0.02) and an earlier stage(59.7% vs 90.9%, P = 0.03). Possible reasons for PCCRC were "missed or new" in 9 patients(82%), "incomplete resection" in 1(9%), and "inadequate examination'" in 1(9%). Among 9 "missed or new" PCCRC, the leading cause was non-polypoid shape for early PCCRC and blinded location for advanced PCCRC.CONCLUSION The PCCRC rate for HD colonoscopy was 0.7%-1.7%, being lower than that for standard-definition colonoscopy(1.8%-9.0%) reported previously employing the same methodology.

New application of endocytoscope for histopathological diagnosis of colorectal lesions

BACKGROUND The endocytoscope with ultra-high magnification(x 520)allows us to observe the cellular structure of the colon epithelium during colonoscopy,known as virtual histopathology.We hypothesized that the endocytoscope could directly observe colorectal histopathological specimens and store them as endocyto-pathological images by the endoscopists without a microscope,potentially saving the burden on histopathologists.AIM To assess the feasibility of endocyto-pathological images taken by an endoscopist as adequate materials for histopathological diagnosis.METHODS Three gastrointestinal pathologists were invited and asked to diagnose 40 cases of endocyto-pathological images of colorectal specimens.Each case contained seven endocyto-pathological images taken by an endoscopist,consisting of one loupe image,three low-magnification images,and three ultra-high magnification images.The participants chose hyperplastic polyp or low-grade adenoma for 20 cases of endocyto-pathological images(10 hyperplastic polyps,and 10 Low-grade adenomas in conventional histopathology)in study 1 and high-grade adenoma/shallow invasive cancer or deep invasive cancer for 20 cases[10 tumor in situ/T1a and 10 T1b]in study 2.We investigated the agreement between the histopathological diagnosis using the endocyto-pathological images and conventional histopathological diagnosis.RESULTS Agreement between the endocyto-pathological and conventional histopathological diagnosis by the three gastrointestinal pathologists was 100%(95%CI:94.0%–100%)in studies 1 and 2.The interobserver agreement among the three gastrointestinal pathologists was 100%,and theκcoefficient was 1.00 in both studies.CONCLUSION Endocyto-pathological images were adequate and reliable materials for histopathological diagnosis.