[Colon cancer in Iceland 1955-2004. Study on epidemiology, histopathology and gender difference]

Colon cancer is the third most common cancer in Iceland. The aim of this study was to analyze the epidemiology and histopathology of colon cancer in Iceland, resection rate and the difference between men and women.

Pathology and autopsy reports for all patients diagnosed with colon cancer between 1955 and 2004 where reviewed. All the histopathology material was re-evaluated. Demographical information and pathological findings were registered. Age-standardized incidence was calculated for both men and women. Gender difference was evaluated. Time trend was evaluated by linear regression.

After re-evaluation 2293 cases remained (1148 males and 1145 females). The incidence increased for men from 7.5, to 22.2/105 and for women from 8.6 to 15.1/105. Most tumors were located in the sigmoid colon (35%). Surgical rate increased from 50% to 85%. Adenocarcinomas where 84% and mucinous adenocarcinoma 7%. Altogether 7% of cases were TNM-stage I, 32% were stage II, 24% stage III, 21% in stage IV and stage was unknown in 16% of cases. Slight gender difference was observed regarding grade, vessel invasion, depth of invasion and anatomic subsite.

Incidence of colon cancer increased considerably, mainly for men. Surgical rate and pathology of colon cancer is similar to that reported elsewhere except that there are somewhat fewer cases in TNM-stage I. Little gender difference was observed in the pathological parameters analysed.