Epidemiological Differences between Colon Cancer and Rectum Cancer

Background: Clinical and epidemiological variation was seen between the colon cancer (CC) and rectum cancer (RC). So, there is not so much data available about the epidemiological and clinicopathological differences and prognostic factors regarding to CC and CR in Iran, we aimed to perform this study.

Methods: All cases of CC and RC referred to oncology and gastroenterology wards of Taleghani General Hospital, Teheran, Iran between 2002 and 2008 were retrospectively reviewed. The research group were reviewed all medical records in the study period for collecting the required data. All patients under study were followed up until end day of 2008 (closed day) from their diagnosis.

Results: There are 856 cases of CC and 427 cases of RC. Mean survival time of CC cases was relatively higher than RC cases (P <0.05). Regarding to the age at diagnosis, about 42% of CC and 42.6% of RC patients was diagnosed less than 50 years of age. Positive family history of any cancer was relatively higher in CC (40.0%) patients than RC (31.0%) patients (P<0.05). significant difference was seen between CC and RC regarding to depth of tumor invasion, pathologic stage and type of first treatment. RC patient were diagnosed in more advanced pathologic stages. Regarding to histology type of tumor 75.0% of CC cases and 79.4% of RC cases was adenocarcinoma. Abdominal pain (74.4%) and blood per rectum (89.7%) were the most prevalent symptoms mentioned by patients for CC and RC, respectively. Distant metastasis, lymph node metastasis, lower BMI and poor grading of tumor was related to increased risk of death due to CC. Regarding to RC, only pathologic stage was determine as prognostic factor.

Conclusion: Results of this study emphasis that RC has a poorer prognosis comparing to CC. Up to 42 percent of patients with CC and RC are lower than 50 years of age. Patterns of CC versus RC indicate major variations in demographic and clinicopathologic characteristics that suggest possible differences in etiology and pathogenesis. So we suggest that for the analysis of cancer data, CC and RC should be investigated as separate cancers and not to be as colorectal cancer. Abdominal pain and blood per rectum should be emphasis for detection of CC and RC, respectively.