Prediagnostic dietary phytosterol intake, inflammatory biomarkers, and colorectal cancer survival: a cohort study.

[BACKGROUND] This study aimed to investigate the association of prediagnostic phytosterol intake (total phytosterols, β-sitosterol, campesterol, stigmasterol, β-sitostanol, and campestanol) with colorectal cancer (CRC)-specific and overall survival and to explore the potential mediating role of systemic inflammation.

[METHODS] This study included 2799 incident CRC patients enrolled in the Guangdong Colorectal Cancer Cohort between 2010 and 2021, who were prospectively followed until December 1, 2024. Usual dietary intake during the year before diagnosis was assessed using a validated food frequency questionnaire. Inflammatory markers were measured from fasting blood samples collected at enrollment, and the pan-immune-inflammation value (PIV) was calculated as neutrophil count × platelet count × monocyte count ÷ lymphocyte count. Multivariable Cox proportional hazards models and mediation analyses were conducted to assess associations between phytosterol intake, inflammation, and CRC survival, adjusting for demographic, clinical, and dietary confounders.

[RESULTS] During a median follow-up of 78.60 months, 717 deaths were recorded, of which 636 were attributable to CRC. Higher intakes of total phytosterols, β-sitosterol, and stigmasterol were significantly associated with improved CRC-specific survival (HRs for Q4 vs Q1: 0.76 [95% CI = 0.60 to 0.95], 0.71 [0.56 to 0.90], and 0.75 [0.60 to 0.95], respectively). Similar associations were observed for overall survival. The PIV showed a significant but modest mediating effect on the associations of β-sitosterol intake with CRC-specific survival (P = .016) and overall survival (P = .018).

[CONCLUSIONS] Higher prediagnostic dietary phytosterol intake was associated with improved CRC survival partially through inflammation-related pathways.