# A biomarker-directed trial of vitamin D after surgery for digestive tract cancers

Source: https://onco.cc/ideas/idea-reg-vitamin-d-digestive-cancer-biomarker-trial/  
OnCo record `idea-reg-vitamin-d-digestive-cancer-biomarker-trial` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

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.

## Summary

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.

## Fields

- Kind: Idea
- Last checked: 2026-09-08
- Hypothesis: Vitamin D3 2,000 IU daily improves 5-year relapse-free survival by at least 10 absolute percentage points in patients with p53-immunoreactive digestive tract cancers after curative surgery.
- Rationale: Subgroup findings from a negative trial are usually false, but this one was pre-specified in part, is mechanistically plausible and is being echoed in a second trial; the cost of a definitive test is trivial relative to the potential benefit in common cancers.
- Proposed test: Randomised placebo-controlled trial of about 800 biomarker-positive patients across Japan and Europe with RFS primary endpoint and serum vitamin D monitoring.
- Maturity: early-clinical
- Actor: research

## Sources

- Bottleneck evidence (No incentive to repurpose cheap drugs): Pantziarka et al., The Repurposing Drugs in Oncology (ReDO) Project (ecancer 2014): https://doi.org/10.3332/ecancer.2014.442

## Connected records

- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/), [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/), [Oesophageal cancer](https://onco.cc/cancers/esophageal/)
- targets: [TP53](https://onco.cc/targets/tp53/)
- bottlenecks: [Biomarkers are not validated or standardised](https://onco.cc/bottlenecks/b-biomarker-validation/), [No incentive to repurpose cheap drugs](https://onco.cc/bottlenecks/b-generic-repurposing/)
- key papers: [The Repurposing Drugs in Oncology (ReDO) Project](https://onco.cc/key-papers/paper-pantziarka-ecancermedicalscience/)
- technologies: [Vitamin D and omega-3 supplementation](https://onco.cc/technologies/vitamin-d-omega3-supplementation/)
- trials: [VITAL (VITamin D and OmegA-3 TriaL)](https://onco.cc/trials/vital/)

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