There have been a number of studies relating vitamin D deficiency to cancer and relapse in different types of cancers, for instance Hodgkin's lymphoma. Yet it does not have any repercussion for medical practice. I believe a large study is needed comparing vit D level in newly diagnosed patients to normal population, and next the progress and relapse of these patients should be monitored. This could turn out to be an important prophylaxes tool.

The role of vit D in Covid-19 patients has recently been studied at last. (Dr Campbell called for such studies in march 2020 based on observed differences in the number of Covid-19 patients with different amount of pigment in their skin while living at the same geographical location) and amazing results have been found. This simple, virtually costless intervention might decrease the number of new cancers especially blood related ones. After all vit D impacts immune system. Current research shows that the adequate value of vit D for proper functioning of the immune system is 40 not 30 ng/ml

It will be interesting to find out, how increased supplementation these day will influence the number of new cancers, though one will need to take into account diagnostic delays of recent months. Would anyone be interested in running such a study? Wouldn't be wonderful if vit D supplementation in new required doses could limit the number of oncology patients if only a little bit? Once vit. D supplementation in children has significantly lowered rickets.