the second question is what if you overdiagnosed. what if you were sitting in this hall of mirrors, constantly being surveyed, this kind of big data is watching you. what would happen? i mean would we start intervening on cancers that we would not otherwise intervene on. maybe those cancers are harmless. so for an oncologist, for me t raises the whole question of diagnosis. you know, where are we going with diagnosis. are we going to overdiagnose, are we going to start invading in the body in a way we hadn't expected to just because as machines learn, they'll keep telling us. >> rose: help me understand the difference. i will always believe that all knowledge is good. the more you knew, the better you were. and you are saying here, if the more you know causes you to take certain kind-- too many tests. >> that's exactly right. and in fact, let me turn it back to you and say all knowledge isn't good in medicine. there are things you don't need to know about. >> rose: that's one thing, say you don't need to know about, i'm not talking a

are we going to overdiagnosed? we going to start invading in the body in a way we did not expect? charlie: help me understand the difference. i always believed all knowledge .s good, the more you knew, the better you where you are saying that if the more you know --ses you to take certain too many tests? siddhartha: exactly. i would say all knowledge isn't good in medicine. there are things you don't need to know about. charlie: i'm not talking about need, i'm talking about what harm does it do? siddhartha: overdiagnosis causes severe harm. you can cut up pieces of the body, biopsy them, there is an economic cost, you might be chasing cancers that, we now know from autopsies that many people will die of cancers that are incidental. for example, a person dies of an automobile accident, you do an autopsy and you find all these cancers. many of them are incidental. they would not die of these cancers.imagine if a machine was telling you i found cancer here not tell but it may you if the cancer will metastasize or beco

the rates from the trials of prostate cancer screening suggests that 20% to 50% of these may be overdiagnosed that is, the diagnosis of of prostate cancer but slow growing and not likely to cause a problem. >> the task force says it couldn't make specific recommendations for african-american men that have the highest risk for prostate cancer and more research for better version or replacement for the psa blood test. the beautiful weather has a lot of people back outside working in their garden or just cleaning up the yard which is great but may also leave people with sore muscles or back pain or injuries, other pedic doctors see people get hurt when they go from mostly resting to jumping back foo the heavy activity with lots of bending and lifting and in the beginning of the season it's best to start slow and give your body time to adjust and doing a warm-up or stretching could help to prevent problems and the more flexible you are the less chances to pull or strain a muscle. try to warm up and take your time and don't overdo it the first few times out. >> i agree. then take a nap. >>> meanti

. >> reporter: 20 to 50% of these may be overdiagnosed. they are diagnosis of pro state cancer but of the type that's slow growing own not likely to cause a problem. >> the task force could not make specific recommendations for african-american men with the highest risk of prostate cancer and calling for a replacement of the psa test. >> in 2017 fashion 1.2 million people watched april the giraffe give birth. april is carrying for her baby boy, you might have seen it on abc yesterday. 45 minutes after the little guy was born at a new york zoo. he stood, albeit, a little wobbliy. the birth was witnessed via live stream. >>> a person is reunited with her family 44 years after she last saw them. nora muchanic was in elmer for the emotional encounter. >> reporter: this was the scene in elmer salem county as a long lost sister was welcomed home by her siblings, the last time they saw was 44 years ago. she ran away from home when she was 16 years old nobody ever heard from her again, but her brothers and sisters didn't forget her. >> i wonder if