Kenta Kodama

Depressed-Type Colonic Lesions and “De Novo” Cancer in Familial Adenomatous Polyposis: A Colonoscopist’s Viewpoint

Familial adenomatous polyposis (FAP) is the most common inherited polyposis syndrome. Almost all patients with FAP will develop colorectal cancer if their FAP is not identified and treated at an early stage. Although there are many reports about polypoid lesions and colorectal cancers in FAP patients, little information is available concerning depressed lesions in FAP patients. Several reports suggested that depressed-type lesions are characteristic of FAP and important in the light of their rapid growth and high malignancy. Here, we describe the occurrence of depressed-type lesions in FAP patients treated at our institution. Between April 2001 and March 2010, eight of 18 FAP patients had colorectal cancers. Depressed-type colorectal cancer was found in three patients. It should be kept in mind that depressed-type lesions occur even in FAP.

Comparison of the endocytoscopic and clinicopathologic features of colorectal neoplasms

Background and aim: Permeation of a vein or lymphatic vessel by a tumor is a key risk factor for lymph node metastasis. We examined the features of colorectal tumor vessel permeation using endocytoscopy, an ultra-high magnifying endoscopic system combined with a narrow-band imaging capability (EC-NBI). Patients and methods: We examined 188 colorectal lesions using EC-NBI before treatment was started. We measured the diameters of tumor vessels on EC-NBI images. We used the tumor vessel diameter (the mean diameter of four tumor-associated vessels) and the variation in tumor vessel caliber (the difference between the maximum and minimum diameters of the vessels expressed as a proportion) to judge changes in vessel formation. We examined the relationship between these variables and the extent of venous or lymphatic vessel permeation (vessel invasion) established by immunohistochemical examination of the resected specimen using monoclonal antibodies against the CD34 and D2u200a–u200a40 antigens. We also analyzed the relationships between tumor vessel diameter, tumor vessel caliber variation, and depth of tumor invasion. Results: There were significant differences in tumor vessel diameter and caliber variation between tumors in situ and T1u200a–u200aT3 carcinomas. In T1 carcinomas, larger tumor vessel diameter and greater tumor vessel caliber variation were significantly associated with venous permeation. In T2 and T3 carcinomas, greater tumor vessel caliber variation was significantly associated with venous permeation. Conclusions: The vessel diameter and caliber variation of colorectal tumor microvasculature are associated with depth of invasion and venous permeation, especially in T1 carcinomas.

Head Invasion' Is Not a Metastasis-Free Condition in Pedunculated T1 Colorectal Carcinomas Based on the Precise Histopathological Assessment

Background/Aim: Previous reports stated that pedunculated T1 colorectal carcinomas with ‘head invasion showed almost no nodal metastasis, requiring endoscopic treatment alone. However, clinically, some lesions develop nodal metastasis. We aimed to validate the necessity of distinguishing between ‘pedunculated and ‘non-pedunculated lesions, and also between ‘head and ‘stalk invasions. Methods: Initial or additional surgery with lymph node dissection was performed in 76 pedunculated and 594 non-pedunculated cases. Among pedunculated lesions, the baseline was defined as the junction line between normal and neoplastic epithelium (Haggitts level 2). The degree of invasion was classified as ‘head invasion (above the baseline) or ‘stalk invasion (beyond the baseline). Clinicopathological factors were analyzed with respect to nodal metastasis. Results: Nine of 76 (11.8%) pedunculated cases and 52/594 (8.8%) non-pedunculated cases developed nodal metastasis (p = 0.40). No significant differences were found in the rate of nodal metastasis between ‘head invasion (4/30, 13.3%) and ‘stalk invasion (5/46, 10.9%). All the 4 cases with ‘head invasion had at least one pathological factor. Conclusions: ‘Head invasion was not a metastasis-free condition. Even for pedunculated T1 cancers with ‘head invasion, additional surgery with lymph node dissection should be considered if these have pathological risk factors.

Mo1936 Characteristics of Colorectal Tumours in Asymptomatic Patients With Negative Immunochemical Faecal Occult Blood Test Results

The immunochemical faecal occult blood test (iFOBT) is a simple, non-invasive colorectal cancer (CRC) screening method for reducing CRC-related mortality. However, the sensitivity of iFOBT is imperfect and certain colonic neoplasms that require removal may be missed. The aim of this study was to investigate the incidence and character- istics of CRC in asymptomatic, iFOBT-negative patients who underwent opportunistic screening. A total of 919 subclinical patients (276 iFOBT-positive and 643 iFOBT-negative) in the health screening program of our hospital underwent total colonoscopy (TCS) within 2 years after iFOBT. The patients were divided into an iFOBT-positive and an iFOBT-negative group and the TCS findings were compared between the two groups. Although the incidence of advanced neoplasia (CRC, high‑grade dysplasia, adenoma sized ≥10 mm and tubulovil- lous adenoma) was significantly higher in the iFOBT‑positive group, these lesions were also found in 6.3% of iFOBT-nega- tive patients. The lesions tended to be proximally located and non-protruding. In conclusion, screening with iFOBT remains clinically significant. However, colonoscopy is indispensable for reducing the incidence and mortality of CRC.