Therapeutic Plan for the Early Colorectal Cancer Defined by Appearance of Growth Mode

Abstract

Two hundred thirty-three cases (288 lesions) of early colorectal cancer were analyzed clinicopathologically to assess if morphology on the cut surface helps determine the therapeutic plan. Materials consisted of 166 cases (220 lesions) of mucosal cancer (m) and 67 (68 lesions) of submucosal cancer (sm). Histopathological data from these cases were examined and compared, with particular emphasis on the growth mode of the malignancy. The growth type of early colorectal cancer was divided into two types, those accompanied by intramucosal polypoid growth (PG-ca) and those with non-polypoid growth (NPG-ca). Of the 68 lesions of sm cancer, lymph node metastasis occurred in 8 patients (11.8%). The incidence of nodal metastasis by morphologic findings on the cut surface 17.2% (5/29) in the NPG-ca type as against 7.7% (3/39) in the PG-ca type. Tumors of the NPG-ca type tended to be smaller (less than 2.0 cm in diameter) than those of the PG-ca type and showed massive invasion of submucosal tissue and 72.4% (21/29) positivity for lymphatic vessel permeation. Therefore those cancers of the with non-polypoid growth type are considered to carry a high risk of lymph node metastasis and a colectomy with lymph node dissection would be the treatment of choice.