ECOG-ACRIN EA8184

This phase II trial studies how well green tea catechins work in preventing progression of prostate cancer from a low risk stage to higher risk stages in men who are on active surveillance. Green tea catechins may stabilize prostate cancer and lower the chance of prostate growing.

URCC-22053

This phase III trial tests whether high-dose vitamin D works in treating androgen-deprivation therapy (ADT)-induced bone loss in patients with prostate cancer who are undergoing androgen-deprivation therapy. Vitamins are substances that the body needs to grow and develop normally. Vitamin D helps the body absorb calcium. Calcium is one of the main building blocks of bone. A lack of vitamin D can lead to bone diseases such as osteoporosis or rickets. This trial may help researcher determine if high-dose vitamin D helps keep bones strong, lowers number of falls, and lessens fatigue in men getting androgen-deprivation therapy.