A biomarker-directed trial of vitamin D after surgery for digestive tract cancers
A Japanese trial found vitamin D supplements did not help everyone after digestive cancer surgery, but appeared to help a subgroup identified by a tumour marker. That subgroup deserves its own trial.
The AMATERASU trial of vitamin D3 after surgery for digestive tract cancers was negative overall, but pre-specified and post-hoc analyses reported large relapse and death reductions in subgroups (p53-immunoreactive tumours, low-to-mid baseline vitamin D). Similar biomarker-restricted signals appeared in SUNSHINE (colorectal, high-dose vitamin D with chemotherapy). Vitamin D is nearly free. The proposal is a confirmatory randomised trial restricted to the biomarker-defined subgroup, with relapse-free survival as the primary endpoint, funded publicly.
- No incentive to repurpose cheap drugs · Old, cheap drugs with anti-cancer signals never get the trials they need because no one profits from the result.
- Biomarkers are not validated or standardised · Tests that decide who gets a drug are often not validated prospectively and are measured differently in every lab.