title: Morphology as a risk factor for the malignant potential of T2 colorectal cancer.
abstract: Currently, depressed type T1 colorectal cancer is often detected and its malignant potential is being revealed. However, few reports have focused on the morphology of T2 colorectal cancer types. The aim of the present retrospective study was to clarify the characteristics of colorectal T2 cancer types derived from depressed type T1 cancer. The present study included 195 patients with colorectal T2 cancer surgically resected at a referral hospital between April 2001 and April 2009. A total of 48 lesions (25%) with lymph node metastasis and 4 (2%) with distant metastasis were found. The lesions were classified by their form during endoscopy into four categories: Group A, depressed type (the periphery consists of normal mucosa); group B, laterally spreading type; group C, protruded type; group D, ulcerative type (the periphery consists of neoplastic mucosa). Tumor size, lymphatic and venous involvement, lymph node metastasis, and distant metastasis were compared between the four categories. The distribution of patients were as follows: Group A, 73 (37%), group B, 26 (13%), group C, 24 (12%) and group D, 72 (37%). The average tumor size for each category was 23, 51, 30 and 36 mm for groups A, B, C and D, respectively. The number of positive findings for lymphatic involvement, venous involvement, lymph node metastasis and distant metastasis for each category were: Group A, 50 (69%), 54 (74%), 19 (26%) and 1 (1%); group B, 14 (54%), 12 (46%), 8 (31%) and 0 (0%); group C, 14 (58%), 8 (33%), 6 (25%) and 0 (0%); group D 35 (49%), 41 (57%), 16 (22%) and 3 (4%). Group A demonstrated a significantly smaller tumor size (P<0.01), and higher rates of lymphatic and venous involvement (P=0.0333 and P=0.0019, respectively). No significant differences were observed between categories with regards to nodal and distant metastases. Of the T2 cancer types, ~40% were the depressed type. Compared with the other forms, depressed type lesions exhibited a smaller tumor size, and higher rates of lymphatic and venous involvement, which suggested these lesions were of a more malignant nature.
authors: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama 225-8503, Japan.
authors: Yuichi
authors: Y
authors: Mori
authors: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama 225-8503, Japan.
authors: Shin-Ei
authors: SE
authors: Kudo
authors: Department of Coloproctology, Aizu Medical Center, Fukushima Medical University, Aizuwakamatsu 965-0803, Japan.
authors: Shungo
authors: S
authors: Endo
authors: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama 225-8503, Japan.
authors: Chiyo
authors: C
authors: Maeda
authors: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama 225-8503, Japan.
authors: Shumpei
authors: S
authors: Mukai
authors: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama 225-8503, Japan.
authors: Yasuharu
authors: Y
authors: Maeda
authors: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama 225-8503, Japan.
authors: Shinichi
authors: S
authors: Kataoka
authors: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama 225-8503, Japan.
authors: Kenichi
authors: K
authors: Takeda
authors: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama 225-8503, Japan.
authors: Katsuro
authors: K
authors: Ichimasa
authors: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama 225-8503, Japan.
authors: Hideyuki
authors: H
authors: Miyachi
authors: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama 225-8503, Japan.
authors: Naruhiko
authors: N
authors: Sawada
authors: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama 225-8503, Japan.
authors: Eiji
authors: E
authors: Hidaka
authors: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama 225-8503, Japan.
authors: Fumio
authors: F
authors: Ishida
keywords: colorectal cancer; depressed type; gross appearance; macroscopic form; morphology