Circulating Folate and Folic Acid Concentrations: Associations With Colorectal Cancer Recurrence and Survival

Abstract

Background: Folates, including folic acid, may play a dual role in colorectal cancer development. Folate is suggested to be protective in early carcinogenesis but could accelerate growth of premalignant lesions or micrometastases. Whether circulating concentrations of folate and folic acid, measured around time of diagnosis, are associated with recurrence and survival in colorectal cancer patients is largely unknown.

Methods: Circulating concentrations of folate, folic acid, and folate catabolites p-aminobenzoylglutamate and p-acetamidobenzoylglutamate were measured by liquid chromatography-tandem mass spectrometry at diagnosis in 2024 stage I-III colorectal cancer patients from European and US patient cohort studies. Multivariable-adjusted Cox proportional hazard models were used to assess associations between folate, folic acid, and folate catabolites concentrations with recurrence, overall survival, and disease-free survival.

Results: No statistically significant associations were observed between folate, p-aminobenzoylglutamate, and p-acetamidobenzoylglutamate concentrations and recurrence, overall survival, and disease-free survival, with hazard ratios ranging from 0.92 to 1.16. The detection of folic acid in the circulation (yes or no) was not associated with any outcome. However, among patients with detectable folic acid concentrations (n = 296), a higher risk of recurrence was observed for each twofold increase in folic acid (hazard ratio = 1.31, 95% confidence interval = 1.02 to 1.58). No statistically significant associations were found between folic acid concentrations and overall and disease-free survival.

Conclusions: Circulating folate and folate catabolite concentrations at colorectal cancer diagnosis were not associated with recurrence and survival. However, caution is warranted for high blood concentrations of folic acid because they may increase the risk of colorectal cancer recurrence.

Figure 1.

Forest plots of subgroup analyses reporting hazard ratios and corresponding 95% CIs for a doubling in folate concentrations and recurrence, overall survival, and disease-free survival. Weights of the effect estimates are from random effects meta-analysis; square dots represent the hazard ratio of each subgroup and diamonds represent the hazard ratio of all subgroups combined. Heterogeneity among subgroups was evaluated using the I² index. CI = confidence interval; IQR = interquartile range; Q = heterogeneity Cochran’s Q test; df = degrees of freedom; I² = heterogeneity I² statistic.