exponential statistical model

Colorectal cancer is one of the important causes of death due to cancer worldwide. Survival time in this cancer should be controlled to decrease the risk of mortality. In this study survival time and factors that could affect it are evaluated.
In the present study, the files of 446 patients afflicted with colorectal cancer who had referred to Taleghani Hospital, Tehran from 1985 to 2013 were chosen as the study group. The exponential model was used here, for the purpose of investigating the survival of patients with colorectal cancer and finding proper variables affecting this survival and longevity.
In this study, the subjects had the mean (standard deviation) survival time 4.52 (0.182) year. The patients’ age at the time of diagnosis (P = 0.002) and tumor size (P = 0.032) were the only significant variables affecting the survival of patients in the exponential model. Sex, the family history of colorectal cancer, the tumor site, and body mass index had no significant effect on the survival time of the patients with colorectal cancer.
The results of the study show that to improve the survival chance of the patients with colorectal cancer or decrease the mortality rate, due attention should be paid to the age of the patient at the time of diagnosis.