Circulating Vitamin D and Selenium Levels and Outcome in Prostate Cancer Patients: Lessons from the MARTINI-Lifestyle Cohort

Abstract

BackgroundDietary agents, in particular vitamin D (Vit D) and selenium, are widely used by prostate cancer (PCa) patients to improve cancer outcomes. ObjectiveTo investigate whether plasma Vit D and selenium levels prior to radical prostatectomy (RP) are associated with worse pathologic tumor characteristics and increased risk of disease recurrence. Design, setting, and participantsA total of 3849 men with PCa scheduled for RP in the Martini-Klinik at the University Hospital Hamburg-Eppendorf, Hamburg, Germany, between January 2014 and December 2018 were included in this study. Outcome measurements and statistical analysisAge, and clinical and laboratory values were collected prior to RP. Biochemical recurrence (BCR) was defined as prostate-specific antigen (PSA) ≥0.2 μg/l and rising after RP. Kaplan-Meier plots depicted BCR-free survival. Cox regression models (adjusted for age, preoperative PSA, pT stage, pN stage, pGG, surgical margin status, and year of surgery) tested the relationship between oncologic outcomes and Vit D and selenium levels. Results and limitationsMedian plasma Vit D and selenium levels were 19.3 and 71 μg/l, respectively. Circulating Vit D and selenium levels correlated inversely with PSA values. Histologic grade, pT stage, and pN stage were not associated with Vit D and selenium levels at the time of RP. In the overall cohort, BCR-free survival at 3 yr of follow-up was 82.9%. When stratified according to median Vit D levels, BCR-free survival at 3 yr of follow-up was 82.7% and 83.0% (p ≤ 0.59). Upon stratification according to median selenium levels, BCR-free survival was 82.2% and 83.7% (p = 0.19). In a multivariable Cox regression model predicting BCR, lower Vit D and selenium levels were not independent predictors of BCR. ConclusionsPlasma Vit D and selenium levels prior to RP were not associated with BCR-free survival. Patient summaryThe results of the MARTINI-Lifestyle cohort could not show a correlation between the occurrence of biochemical recurrence of prostate cancer after radical prostatectomy and the serum levels of vitamin D and selenium. A recommendation should therefore be made to compensate for a potential deficiency and not with the expectation of a reduction in the risk of progression.