>> i have been over-treated, over-diagnosed, over-scared.lison: senior investigative reporter lisa fletcher goes to leading cancer doctors to talk about stage zero and the aggressive treatment. >> a very confusing thing. zero is zero. alison: what she uncovered, next. to take on the "tom insurance companies and the credit card companies and the wall street banks... that's what tom perriello is about." progressive causes have been my life's work. i'm tom perriello... and before and after congress i led non-profits to battle climate change, poverty and president bush's attacks on civil rights. now i'm running for governor to reduce economic inequality. a virginia that works for everyone. alison: the word cancer strikes fear into everyone. last year, nearly 1.7 million people in the u.s. were connected with it. jonathan: there is an increasingly loud conversation going on that the medical community needs to reevaluate many aggressive treatment should never happen. investigative reporter lisa fletcher looks at the trend of t