The results suggest that a high level of vitamin D3 at the time of diagnosis, and thus, during cancer treatment, may improve prognosis of the three cancer types studied.
It pays to keep your 25(OH)D level above 55ng 137.5nmol/l. At that level not only does your body have sufficient vitamin D for it's daily needs but it also has sufficient to maintain a reserve for emergency use.
It's easy and quite cheap to get tested and the
D3 supplements needed are also dirt cheap.
How Vitamin D Reduces Incidence of Cancer: This video explains the role of vitamin d deficiency in the initial stages of cancer development.
Vitamin D Prevents Cancer: Is It True? and this gives a more general overview of the role of Vitamin D3 in cancer prevention.
While of course Breast Cancer and Prostate cancer are not exactly the same there are things about them that are common to both, Particularly the association of low vitamin d status raising incidence levels and worsening prognosis and mortality.