Early detection of cancer is promoted by annual oral examination. monthly BSE from age 20. annual chest x-ray. yearly digital rectal examination for persons over age 40. annual Pap smear from age 40 and annual physical and blood examination. Letter B is wrong because it says Pap smear should be done yearly for sexually active women. All women should have an annual pap smear by age 40 and up whether sexually active or not.