High-dose vitamin D supplementation and prostate cancer progression: a phase II randomised trial in localised prostate cancer cases with intermediate risk of progression (ProsD).

High-dose monthly vitamin D supplementation did not significantly improve active therapy-free survival compared to placebo in men with localised prostate cancer on active surveillance.

• 123 randomised participants were included: 81 in the vitamin D arm and 42 in the placebo arm.
• The intervention was a monthly oral dose of cholecalciferol 50,000 IU.
• There were no appreciable differences in active therapy-free survival between arms (p log-rank = 0.44).
• Participants were aged 50–80 years with a mean (SD) age of 66.5 (6.6) years.
• The trial was a phase II double-blinded randomized design.

High-dose monthly vitamin D supplementation did not significantly improve progression-free survival compared to placebo.

• Progression-free survival was a secondary endpoint of the trial.
• There were no appreciable differences in progression-free survival between the vitamin D and placebo arms (p log-rank = 0.60).
• 123 participants were included in the analysis across both arms.

Monthly vitamin D supplementation significantly raised serum 25(OH)D levels in the treatment arm compared to placebo.

• Mean (SD) baseline 25(OH)D levels were 72.0 (19.9) nmol/L in the vitamin D arm and 66.4 (18.4) nmol/L in the placebo arm (p = 0.1).
• At 24 months, mean (SD) 25(OH)D levels were 91.9 (19.9) nmol/L in the vitamin D arm and 60.4 (24.4) nmol/L in the placebo arm.
• This represents a rise of approximately 19.9 nmol/L in the vitamin D arm and a decline of approximately 6.0 nmol/L in the placebo arm over 24 months.

Vitamin D supplementation was associated with declines in some lymphocytic cytokinesis-block micronucleus cytome (CBMN) markers of genome damage.

• Blood samples were analysed for CBMN markers for lymphocytic genome damage.
• Declines were observed in some of the lymphocytic CBMN markers in the vitamin D arm.
• The authors suggest that reduced prevalence of CBMN markers may indicate a potential biological benefit of vitamin D supplementation.
• No specific p-values for CBMN marker changes are reported in the abstract.

There were no appreciable differences in adverse events between the vitamin D and placebo arms.

• Occurrence of adverse events was assessed in both trial arms.
• No appreciable differences in adverse events were observed between the vitamin D (50,000 IU monthly) and placebo groups.
• This was a phase II trial enrolling men aged 50–80 years with newly diagnosed low-intermediate risk prostate cancer.

The ProsD trial enrolled newly diagnosed low-to-intermediate risk prostate cancer cases on active surveillance as the study population.

• Eligibility criteria included age between 50 and 80 years and placement on active surveillance.
• Participants had localised prostate cancer with intermediate risk of progression.
• The trial was registered in the Australia New Zealand Clinical Trials Registry (ACTRN12616001707459).
• The primary endpoint was active therapy-free survival and the secondary endpoint was progression-free survival.