Serum Pyridoxal 5'-Phosphate and Pyridoxic Acid Ratio Index with Prognosis of Colorectal Cancer: A Prospective Cohort Study.

BACKGROUND

Studies on the association between serum vitamin B6 status and colorectal cancer prognosis are limited and have yielded inconsistent results. This study investigated the association of pyridoxal 5'-phosphate (PLP) and pyridoxic acid ratio (PAr) index with colorectal cancer survival.

METHODS

A total of 1286 colorectal cancer patients diagnosed since 2010 were selected from the Guangdong Colorectal Cancer Cohort study. Serum levels of PLP, pyridoxal, and 4-pyridoxic acid were measured using ultra-high-performance liquid chromatography-tandem mass spectrometry. The study followed overall mortality and colorectal cancer-specific mortality until December 2023. Multivariable Cox proportional hazards regression models were applied to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs). Restricted cubic spline and stratified analysis were performed.

RESULTS

During a median follow-up of 77.36 months, 331 deaths were recorded, with 293 specifically attributed to colorectal cancer. Higher PLP levels were associated with a longer overall survival (HRQ4 vs. Q1, 0.63; 95% CI: 0.46, 0.87; p for trend = 0.008) and colorectal cancer-specific survival (HRQ4 vs. Q1, 0.62; 95% CI: 0.44, 0.87; p for trend = 0.006). Non-linear associations were observed between serum PLP and overall and colorectal cancer-specific survival (p for non-linear < 0.05). However, PAr was not significantly associated with either overall survival (HRQ4 vs. Q1, 1.03; 95% CI: 0.75, 1.41) or colorectal cancer-specific survival (HRQ4 vs. Q1, 1.01; 95% CI: 0.72, 1.42). The association between serum PLP and both overall survival and colorectal cancer-specific survival (p for interaction < 0.05) varied by alcohol drinking status.

CONCLUSIONS

Higher serum PLP levels, but not PAr, may be associated with improved overall and colorectal cancer-specific survival.