Patterns of survival for anatomical sites of colorectal cancer with shift to advanced lesions in Iran.

Background: With a background of disparities in colorectal cancer (CRC) incidences/mortality across countries due to differences in exposure to various prognostic factors, this study aimed to evaluate the site-specific pattern for the survival of colon and rectal patients. Methods: A total of 1,283 patients with CRC diagnosis according to the pathology report of cancer registry of RCGLD from 1 January 2002 to 1 October 2007, were entered into the study. Data were analyzed using univariate and multivariate competing risk survival analysis. Results: Survival proportion of patients showed a significant trend for 1, 3 and 5 year survival in colon cancer (P<0.001) but this wasn’t significant for rectal cancer (P=0.078). Tumor grade and pathologic stage were the most important factors predicting the survival in colon and rectal cancers with stronger hazard in the rectal site for grade and stronger hazard in the colon site for stage. For colon site, in the well and moderate categories of tumor grade, shifting from early to advance stage and also shifting in tumor grade from well and moderate categories to poor tumor grade had a considerable effect in hazard ratios. For rectum site, well to moderate shifting in tumor grade increased the hazard of death and shifting from early to advance stage increased the hazard equal to 2.54 and 4.36 times within the well and moderate tumor differentiation, respectively. In shifting to advance CRC, colon site had generally worse hazard than the rectum. Conclusion: Due to the worse conditions of CRC patients as shifting to advance cancer, to improve the effectiveness of treatment and hence the survival of Iranian patients, we should pay more attention to early detection, in particular by implementing population based screening programmes.