Prognostic factors and survival of colorectal cancer in Kurdistan province, Iran: A population-based study (2009–2014)

Colorectal cancer (CRC) survival varies at individual and geographically level. This population-based study aimed to evaluating various factors affecting the survival rate of CRC patients in Kurdistan province. In a retrospective cohort study, patients diagnosed as CRC were collected through a population-based study from March 1, 2009 to 2014. The data were collected from Kurdistan's Cancer Registry database. Additional information and missing data were collected reference to patients’ homes, medical records, and pathology reports. The CRC survival was calculated from the date of diagnosis to the date of cancer-specific death or the end of follow-up (cutoff date: October 2015). Kaplan–Meier method and log-rank test were used for the univariate analysis of survival in various subgroups. The proportional-hazard model Cox was also used in order to consider the effects of different factors on survival including age at diagnosis, place of residence, marital status, occupation, level of education, smoking, economic status, comorbidity, tumor stage, and tumor grade. A total number of 335 patients affected by CRC were assessed and the results showed that 1- and 5-year survival rate were 87% and 33%, respectively. According to the results of Cox's multivariate analysis, the following factors were significantly related to CRC survival: age at diagnosis (≥65 years old) (HR 2.08, 95% CI: 1.17–3.71), single patients (HR 1.62, 95% CI: 1.10–2.40), job (worker) (HR 2.09, 95% CI: 1.22–3.58), educational level: diploma or below (HR 0.61, 95% CI: 0.39–0.92), wealthy economic status (HR 0.51, 95% CI: 0.31–0.82), tumor grade in poorly differentiated (HR 2.25, 95% CI: 1.37–3.69), and undifferentiated/anaplastic grade (HR 2.90, 95% CI: 1.67–4.98). We found that factors such as low education, inappropriate socioeconomic status, and high tumor grade at the time of disease diagnosis were effective in the poor survival of CRC patients in Kurdistan province; this, which need more attention.