Comparison of Survival between Patients with Hereditary Non Polyposis Colorectal Cancer (HNPCC) and Sporadic Colorectal Cancer

Background: Hereditary non polyposis colorectal cancer (HNPCC) appears to have a better prognosis than sporadic cancer. In the present study we evaluated the clinical outcomes of HNPCC patients with their sporadic colorectal cancer counterparts arising from the general population recorded in a population-based cancer registry in Iran. Patients and methods: The population studied consisted of 121 individuals including 61 patients with sporadic colorectal cancer and 60 with HNPCC who were followed-up between 2003 and 2008 in Taleghani Hospital Tehran. The subjects with HNPCC were screened according to Amsterdam criteria II and Bethesda Guidelines. Subjects with sporadic cancer had no familial history of colorectal cancer. Observed survival was estimated using the Kaplan-Meier method and compared with the log rank test. Multivariate analysis was performed using Cox' regression analysis. Results: In the HNPCC group, 85.0% showed tumors in the colon, vs. 68.9% in the sporadic cancer group. The 5-year survival was 82.5% in the HNPCC study group compared with only 56.4% in the sporadic colorectal cancer group (P=0.044). The age distribution at diagnosis of sporadic patients was significantly higher than HNPCC patients (mean 50.1 years vs 44.3 years P=0.008). The hazard ratio for sporadic cases was 2.93 (95% CI 1.06-8.11) compared with the HNPCC group (P=0.038). Conclusion: Our findings corroborate the results of previous studies which showed overall survival of colorectal cancer in patients with HNPCC is better than with sporadic CRC patients.