High serum folate is associated with reduced biochemical recurrence after radical prostatectomy: results from the SEARCH Database.

INTRODUCTION To analyze the association between serum levels of folate and risk of biochemical recurrence after radical prostatectomy among men from the Shared Equal Access Regional Cancer Hospital (SEARCH) database. MATERIALS AND METHODS Retrospective analysis of 135 subjects from the SEARCH database treated between 1991-2009 with available preoperative serum folate levels. Patients' characteristics at the time of the surgery were analyzed with ranksum and linear regression. Uni- and multivariable analyses of folate levels (log-transformed) and time to biochemical recurrence were performed with Cox proportional hazards. RESULTS The median preoperative folate level was 11.6 ng/mL (reference = 1.5-20.0 ng/mL). Folate levels were significantly lower among African-American men than Caucasians (P = 0.003). In univariable analysis, higher folate levels were associated with more recent year of surgery (P < 0.001) and lower preoperative PSA (P = 0.003). In univariable analysis, there was a trend towards lower risk of biochemical recurrence among men with high folate levels (HR = 0.61, 95 %CI = 0.37-1.03, P = 0.064). After adjustments for patients characteristics' and pre- and post-operative clinical and pathological findings, higher serum levels of folate were independently associated with lower risk for biochemical recurrence (HR = 0.42, 95 %CI = 0.20-0.89, P = 0.023). CONCLUSION In a cohort of men undergoing radical prostatectomy at several VAs across the country, higher serum folate levels were associated with lower PSA and lower risk for biochemical failure. While the source of the folate in the serum in this study is unknown (i.e. diet vs. supplement), these findings, if confirmed, suggest a potential role of folic acid supplementation or increased consumption of folate rich foods to reduce the risk of recurrence.