Breast cancer and prostate cancer are the most prevalent malignancies in the Polish population. Their incidence is increasing annually; thus, it is prudent to pursue novel therapeutic pathways. In recent years, there has been growing interest in the use of vitamin D, which exerts anticancer effects at the cellular level. Vitamin D supplementation in states of its deficiency reduces the risk of cancer development. Studies also indicate that vitamin D can slow the progression of cancer and increase the survival rate of cancer patients. Moreover, its effectiveness in advanced stages of the disease is also being investigated. Vitamin D supplementation has been shown to reduce the pain associated with metastasis, particularly bone metastasis. Given the increasing proportion of cancer patients undergoing chemotherapy and thus experiencing the adverse effects of treatment, vitamin D is also being explored as a means of alleviating these effects. The purpose of this publication is to

ummarise the results of studies conducted to date on the use of vitamin D in the pathophysiology, prevention, and treatment of cancer.