Colorectal carcinoma: a retrospective, descriptive study of age, gender, subsite, stage, and differentiation in Iran from 1995 to 2001 as observed in Tehran University.

PURPOSE: Colorectal carcinoma is one of the most common cancers in the world as well as in Iran. There are differences in subsite of the carcinoma when considering age and gender. This study was designed to describe the distribution of colorectal carcinoma by age at diagnosis, gender, and subsite of the tumor. These factors also are evaluated in conjunction with disease stage and tumor differentiation at the time of diagnosis.
METHODS: Data from 419 patients from a population that receives no screening between April 1995 and March 2001 operated on in the Cancer Institute and Imam Khomieni Hospital with a diagnosis of colorectal cancer were used to describe distribution of the colorectal carcinoma by age, gender, tumor subsite and pathology, and stage at diagnosis.
RESULTS: There were 403 (96.2 percent) cases of adenocarcinoma. Males and females constituted 52.4 and 47.6 percent of cases, respectively. The mean age was 52.3 years. Patients were divided into two age groups (40 years and younger, and older than 40 years); 16.4 percent of patients had tumors in the proximal colon and 83.6 percent in distal parts. Most patients were Stage II and III (48.1 and 33.4 percent, respectively). Tumor subsite distribution was almost the same between the two age groups (aged 40 years and younger: proximal, 18.5 percent, and distal, 81.5 percent; older than aged 40 years: proximal, 15.7 percent, and distal, 84.3 percent). Most patients in the younger age group were Stage III (45 percent) and in the older age group were Stage II (53.2 percent; P<0.001). Tumor differentiation proportions in patients aged 40 years and younger were: good, 24.4 percent; moderate, 53.6 percent; poor, 22 percent; and in patients older than aged 40 years were: good, 41.5 percent; moderate, 52.6 percent; poor, 5.9 percent (P<0.001). There were no differences in stage and tumor differentiation between two genders, but most of the patients with tumors in proximal colon were males (62.5 percent; P=0.1).
CONCLUSIONS: Most of the colorectal carcinomas were in distal parts in our study, so most of these carcinomas can be detected by proctosigmoidoscopy. Because younger patients had more advanced disease, the importance of screening and "clinical suspicion" in the young is important.