I've been diagnosed cancer-free..how accurate is that ?

Great News!: Are you speaking in general terms following screening tests (mammography, colonoscopy, psa) or have you been treated for a cancer that is now gone? If you are asking about the latter, it really depends upon the type of cancer you had, the stage, and the sensitivity of the tests we have to detect cancer. It's always a challenge living w/this uncertainty--your oncologist can help you a great deal.