Carcinoma of the colon in Iceland 1955-1989. An investigation of survival according to various pathological parameters.

The purpose of this study was to estimate various pathological parameters of colon carcinoma over a 35 year time period and evaluate their effect on survival of the patients. All pathological specimens from patients diagnosed with colon carcinoma in Iceland in the period 1955 to 1989 were re-evaluated in order to determine the following pathological parameters: Tumour size, gross appearance, tissue type, grade, Dukes stage, lymphatic and/or blood vessel invasion, lateral margin involvement, Jass-group of tumour, peritumoural lymphocytic infiltrate, limitation of tumour growth to bowel wall, lymph node metastases, invasive tumour margin and colloid component in adenocarcinoma. Also the following parameters were determined in every case: Age at diagnosis, sex, year of diagnosis and tumour location within the bowel. All these parameters were evaluated with respect to survival of the patients. According to the Icelandic Cancer Registry 1265 patients were diagnosed with colon cancer in Iceland in the period under investigation. After re-evaluation 1205 patients fulfilled the criteria of a primary colon cancer and of those we were able to re-evaluate specimens from 1109 patients to determine histopathological parameters. In a univariable analysis most of the parameters investigated proved significant with respect to survival, except sex, anatomical location of tumour within the bowel, and the proportion of colloid component of tumour. In a multivariable analysis the age at diagnosis proved important as well as the year/period of diagnosis. The following pathological parameters evaluated had a significant prognostic input with regard to survival: Tumour grade, Dukes stage, number of lymph nodes with metastases, peritumoral lymphocytic infiltrate, lateral margin involvement in the surgical specimen and invasive growth pattern of tumour margin. Many pathological parameters are important in regard with prognostic evaluation of patients diagnosed with colon cancer. We suggest that pathologists should include in their surgical pathology specimen reports of colon cancer, in addition to traditional parameters, an evaluation of peritumoral lymphocytic infiltrate, lateral margin involvement with tumour and the growth pattern of tumour at the invasive margin.