“Invasive Pattern” Disclosed with Magnifying Chromo-Endoscopy Is an Indication for Surgical Treatment of Sessile Colorectal Polypoid and Non-Polypoid Lesions

Abstract

Background: by using magnifying colonoscopy it is possible to diagnose a typical pit pattern called invasive pattern (type V) which consists of irregular, distorted colonic gland crypts in a demarcated area. Such pattern is strongly associated with submucosal invasive cancer. Aims: to evaluate the effectiveness of magnifying chromo-endoscopy in differentiating the “invasive pattern” from the rest (“noninvasive patterns”) and assess the correlation with histopathological findings. Methods: a total of 53 sessile or flat colorectal lesions were evaluated in our hospital from December 2002 to October 2003 using chromoendoscopy with 0.4% indigo carmine and magnifying colonoscopy (Olympus CF-Q160Z). Pit pattern was classified as “invasive pattern” or “noninvasive pattern” during colonoscopy procedures. All lesions, endoscopically or surgically resected, were histologically evaluated and compared with the pit pattern diagnosis performed previously. Results: Of the 19 lesions endoscopically diagnosed as having an invasive pattern, 94.7% were submucosal invasive cancers (sm slight: 8.7%, sm deep: 86.0%), while in the remaining 34 lesions, endoscopically diagnosed as having a noninvasive pattern, 97.7% were intramucosal lesions (adenoma: 84.0%, m cancer: 13.7%). Conclusions: among the lesions which were endoscopically diagnosed as having an “invasive pattern” a high percentage was invasive cancer, especially sm deep invasive cancer, where surgical resection is undoubtedly the adequate treatment. On the other hand, the lesions, which were endoscopically diagnosed as having a “noninvasive pattern” were mostly intramucosal lesions, where endoscopic resection is feasible.