Optimal Selenium for Bowel Polyps (OSCAR)

Summary

New Zealand (NZ) has high bowel cancer rates, which the Bowel Screening Programme aims to reduce by early detection of bowel cancer and its precursor, adenomas (polyps). Bowel cancer and adenoma rates are higher in countries like NZ with low intake of the essential trace mineral selenium. Overseas, trials of selenium supplements reduced adenoma recurrence in people with low blood selenium, but not with high levels (where adding selenium increased health risks). Laboratory research explained this, and found certain types of selenium are safer and more effective. The optimal type and dose of selenium to use in NZ cancer prevention trials is not known. The goal of this clinical trial is to find out how to achieve the optimal amount of body selenium in people who have had a high risk bowel adenoma removed. The main questions it aims to answer are: * what dose of selenium taken by mouth will maximise levels of the main selenium protein in blood; * whether one type of organic selenium is better than the other at increasing blood levels of this selenium protein; * whether a larger dose of selenium is needed in people who start with lower blood selenium levels; Participants will take one selenium capsule a day for 6 weeks then two capsules a day for 6 weeks. Each participant will have blood tests at baseline, then blood tests and evaluation of side effects at 6 weeks and 12 weeks. Researchers will compare these results in the participants taking each type of selenium (selenomethionine or methylselenocysteine).

Timeline

Start

2022-05-06

Primary completion

2023-12-11

Completion

2023-12-11

Drugs

Indications