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

Abstract

Background: Dietary agents, in particular vitamin D (Vit D) and selenium, are widely used by prostate cancer (PCa) patients to improve cancer outcomes.

Objective: To 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 participants: A 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 analysis: Age, 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 limitations: Median 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.

Conclusions: Plasma Vit D and selenium levels prior to RP were not associated with BCR-free survival.

Patient summary: The 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.

Keywords: Prostate cancer; Recurrence; Selenium; Tumor characteristics; Vitamin D.