Image enhanced endoscopy enables differentiation of neoplastic from non-neoplastic colorectal lesions and has been established as a valid modality. Chromoendoscopy with indigo-carmine (IC) dye-spraying and narrow band imaging (NBI) are two of the most popular IEE modalities and has been widely used in clinical setting.
Prediction of invasion depth in cancerous neoplasm is of utmost importance. Under-estimate of invasion depth many lead under-treatment and over-estimation may lead to over-surgery. The former incur recurrence of the cancer and its related death was reported to be as high as 40%. The later may expose patients to unnecessary operation with related complications and affect the quality of life as well. Endoscopic prediction of invasion depth, however, requires more sophisticated observation technique to differentiate those with and without submucosal deep invasion. In Japan, CE with crystal violet dye (CECV) staining with magnifying observation is most widely used and considered as the most accurate way for this purpose by delineating Kudo type V pit pattern to guide treatment (endoluminal vs. surgery). Crystal violet dye is, however, not available in many other countries and the training in predicting invasion depth is lacking. The newly developed JNET classification system is developed for the same purpose without using dye. Current studies applying JNET system for predicting invasion depth revealed promising results but it is challenging for non-Japanese doctors without previous experience of magnifying observation and CECV. Moreover, most of the current studies are conducted by Japanese researchers with previous experience of CECV but whether the results are generalizable to other countries or in non-academic setting is intriguing and needs further validation. Finally, developing an effective training system or module is indispensible for promotion of this classification system. |
