<P> Vitamin supplementation does not appear to be effective at preventing cancer . While low blood levels of vitamin D are correlated with increased cancer risk, whether this relationship is causal and vitamin D supplementation is protective is not determined . One 2014 review found that supplements had no significant effect on cancer risk . Another 2014 review concluded that vitamin D may decrease the risk of death from cancer (one fewer death in 150 people treated over 5 years), but concerns with the quality of the data were noted . </P> <P> Beta - carotene supplementation increases lung cancer rates in those who are high risk . Folic acid supplementation is not effective in preventing colon cancer and may increase colon polyps . It is unclear if selenium supplementation has an effect . </P> <P> Vaccines have been developed that prevent infection by some carcinogenic viruses . Human papillomavirus vaccine (Gardasil and Cervarix) decrease the risk of developing cervical cancer . The hepatitis B vaccine prevents infection with hepatitis B virus and thus decreases the risk of liver cancer . The administration of human papillomavirus and hepatitis B vaccinations is recommended when resources allow . </P> <P> Unlike diagnostic efforts prompted by symptoms and medical signs, cancer screening involves efforts to detect cancer after it has formed, but before any noticeable symptoms appear . This may involve physical examination, blood or urine tests or medical imaging . </P>

Will radiation therapy in medicine be a large part of the future