Can a person prevent cancer ?

No: Well there are some cancer prevention techniques, much of this is related to genetics and unavoidable environmental exposure. Nobody can prevent all cancers. Hope this helps!

Not altogether: The single most helpful thing you can do is not use tobacco. Protect yourself from the nastiest HIV with the vaccine (men and women). Don't abuse alcohol; if you have hepatitis B and/or C, manage them. Use sunscreen. Mammography and breast self-exam catch stuff in time; colon screening does as well. Antioxidants and nutritional supplements to prevent cancer and diet are less clearly helpful.