Interaction between obesity and vitamin D and testosterone and vitamin D in prostate cancer patients on active surveillance in the PROVENT trial.

Abstract

401 Background: PROVENT was a multicentre double blind 3x2 placebo controlled phase II trial to evaluate Vitamin D and Aspirin in low risk prostate cancer during active surveillance. This planned translational research, reports results on levels of obesity in the cohort and investigates the interaction of obesity on pre-trial Vitamin D and Testosterone levels. Methods: Details of the trial are published elsewhere (DOI: 10.1002/bco2.169). The trial protocol (https://www.isrctn.com/ISRCTN91422391) was approved by National Research and Ethics Service (REC reference 14/LO/2033). Blood taken before starting treatment was stored in onsite tissue bank (doi.org/10.3390/cancers17010070). Statistics on median weight and Vitamin D levels and testosterone and vitamin D levels have been studied by Wilcoxon Sum Rank test and Chi-squared test. Results: 104 patients were recruited in 10 months. 52% (54/104) were overweight (BMI 25-29.9) and 22% (23/104) obese (BMI=>30). The median weight was 83.6 kilos. Those with a weight lower than the median had >35 nanomol/L Vitamin D in 75% (38/48) while those with a weight => median had =< 35 nanomol/L Vitamin D in 41.2% (21/51, X 2 3.86, p< 0.05). Study of Vitamin D and Testosterone interaction showed a non-significant trend for more patients with Testosterone <12 nmol/L in those with <50ng/ml vitamin D (12/17=41.4%) than those with ≥50 ng/ml (15/31=31.6% X 2 =pNS). Conclusions: Though the data presented did not produce strong statistically significant findings, in both Vitamin D and obesity and Vitamin D and testosterone studies the % difference was equal to the % difference in meta-analyses reporting statistical significance for 100 times larger patient numbers. Given that overweight and obesity predictors poor outcome and Chandler, D. et al 2020 demonstration that Vitamin D supplements did not reduce incidence of cancer in overweight and obese subjects, further studies of vitamin D and the new obesity drugs GLP-1RA in prostate cancer are justified.