The association of smoking and opium consumption with the risk and prognosis of colorectal cancer: A multicenter retrospective cohort study

Colorectal cancer (CRC) is among the leading global causes of cancer-related morbidity and mortality. While lifestyle factors such as smoking and opium use have been implicated in CRC risk and prognosis, their clinicopathological and survival associations remain unclear. This study aimed to evaluate the impact of these exposures on CRC development, tumor characteristics, and overall survival (OS). A retrospective cohort study with a total of 270 participants aged ≥45 years from 2019 to 2020 was conducted in a multicenter design. Participants were divided into 2 groups of patients with CRC who underwent elective surgery and patients who were admitted for noncancerous conditions. Exposures to smoking and opium, clinicopathological profiles, laboratory data, and survival outcomes over a 5-year follow-up were extracted retrospectively via medical records. Adjusted and unadjusted odds ratios (OR) were computed to identify predictors of CRC development using binary logistic regression analysis. Kaplan-Meier and multivariable Cox regression analyses assessed survival differences and hazard ratios by clinicopathological characteristics. Smoking was more prevalent among CRC patients than controls (P = .041) and was associated with higher CRC risk in univariate logistic regression (OR = 2.19, 95% confidence interval 1.01-4.72; P = .045), though this association was not significant after adjustment (OR = 2.26, 95% confidence interval 0.96-5.27; P = .059). Opium consumption showed no significant association with CRC risk (P = .374), except for a lower platelet count among users (P = .023). In multivariate analysis using Cox regression, neither smoking nor opium use was significantly associated with OS. Kaplan-Meier curves confirmed no survival differences between exposed and unexposed groups. Smoking showed a potential role in CRC development, while opium consumption was not linked to prognosis. These findings highlight lifestyle exposures as possible contributors to CRC risk, warranting further investigation in larger cohorts.