Overall Survival and 3-Years Survival Analysis of Colorectal Cancer Patients and Association with Clinico-pathological Aspects in East Azerbaijan during 2015-2017 Using Population Based Cancer Registry Data

Abstract

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of death from cancer in the world. Currently, CRC is the fourth most common cancer in men and the second common cancer in women of all ages in Iran. Due to the high incidence of colorectal cancers and cancer-related mortality in Iran and East Azerbaijan Province, it is necessary to conduct an epidemiological study on incidence and mortality rates, survival, sex distribution and morphological types of colorectal cancers. The aim of this study was to determine the epidemiologic profile of CRC along with CRC specific survival analysis. Materials and Methods: This was an analytical cross-sectional study using the East Azerbaijan Population Based Cancer Registry database (EA-PBCR) as a source for data related to patients with a diagnosis of CRC. Colorectal cancer specific 1- to 5-year survival analysis and mortality rates were calculated. Log-rank test and Cox regression analysis was performed to test the equality of survival function and mortality hazard. Results: A total of 2,366 newly diagnosed CRCs were registered during 3 years, with a male: female ratio of 1.31. Overall survival rate was 49.8%. One- to 5-year survival rates were 96.21%, 56.94%, 48.62%, 47.88% and 46.76% respectively. At multivariate level, after adjusting for all variables, regression analysis showed that the hazard of mortality in stage IV cancers was 46.44 times higher than that in stage I cancers (HR=46.44, 95% CI: 14.86-145.14, p=0.000). However, differences in patients’ age group and sex and the subsite of cancer did not create any statistically significant variation between groups in regards to mortality hazards (p>0.05).