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> "but [can also] find cancers that were never going to matter." I'm not sure, but isn't better to know that you have it and then investigate further, do more

> "but [can also] find cancers that were never going to matter." I'm not sure, but isn't better to know that you have it and then investigate further, do more tests, perhaps do some period follow-up with a shorter interval? Otherwise it's just betting: I bet that I don't have a lung cancer that will be agressive....

hackeraccount 8y ago
"investigate further" is the sticking point. You're swimming in the ocean and notice something beneath you. Is it a friendly dolphin or a dangerous shark? Do you hold your breath and do a deep dive to figure out which it is? Keep in mind the deeper you go the greater the chance that you'll drown. It's a strained analogy but I think it gets at the problem. What if you dive a little bit deep - some minor test - and still aren't sure? Go deeper - a more invasive dangerous test - or go back to the surface? And what if you dive and are pretty sure it's a shark? Swimming all the way to shore (i.e. cancer treatment) is very risky but the shark will almost certainly kill you. How sure are you, really?
- maxxxxx 8y ago
  “You're swimming in the ocean and notice something beneath you. Is it a friendly dolphin or a dangerous shark? Do you hold your breath and do a deep dive to figure out which it is? Keep in mind the deeper you go the greater the chance that you'll drown.” Does it really make a difference what it is? Will you do anything differently?
  - RyJones 8y ago
    I ask this question about metrics constantly. "If you had this information a year ago, what decisions would have been different?" It usually ends in dropping the request for another metric
  - plink 8y ago
    Absolutely. So called "friendly" dolphins are often very sexually aggressive. With knowledge of what aquatic beast lurked in the depths below, I could tailor my preparedness to either be on guard against unwelcome mammalian advances, or remain blithely unconcerned over some incurious, nimrod fish.
- nradov 8y ago
  I understand your point, but let's dispel the myth of dangerous sharks. The vast majority of shark species never attack humans at all and it's totally safe to swim near them.
MereInterest 8y ago
* Choice A: X% chance of aggressive cancer, which worsens as it is left untreated. * Choice B: X% chance of finding and treating aggressive cancer. Y% chance of false positive leading to significant side effects. If Y is zero, then the choice to do further testing is obvious. If Y is large, then it depends on how large the side effects are, and what the chance of running into them is. You have risk in either case, and you will never reduce risk to zero. The question is how much risk you have, and what cost there is to mitigate that risk.
thebeefytaco 8y ago
Nope. When it comes to tumors, doctors always play 'better safe than sorry', but the treatments available for cancer are so detrimental that it's going to do way more harm than good to receive treatment for something that was benign. A little bit of information can be a dangerous thing.
rurp 8y ago
The issue is that testing often comes with its own health costs and many tests return a fairly high rate of false positives, which in turn leads to surgeries that can take a high toll on the body. Related to this, I recall reading about a study of elderly men with slow growing prostate cancer. Having surgery to remove the cancer did decrease the chance of dying from prostate cancer, but actually reduced their overall life expectancy. Prostate cancer surgery is hard on the body and an older person with a slow moving cancer has a pretty good chance of dying from some other cause before the cancer gets them.

hackeraccount 8y ago

"investigate further" is the sticking point. You're swimming in the ocean and notice something beneath you. Is it a friendly dolphin or a dangerous shark? Do you hold your breath and do a deep dive to figure out which it is? Keep in mind the deeper you go the greater the chance that you'll drown. It's a strained analogy but I think it gets at the problem. What if you dive a little bit deep - some minor test - and still aren't sure? Go deeper - a more invasive dangerous test - or go back to the surface? And what if you dive and are pretty sure it's a shark? Swimming all the way to shore (i.e. cancer treatment) is very risky but the shark will almost certainly kill you. How sure are you, really?

maxxxxx 8y ago
“You're swimming in the ocean and notice something beneath you. Is it a friendly dolphin or a dangerous shark? Do you hold your breath and do a deep dive to figure out which it is? Keep in mind the deeper you go the greater the chance that you'll drown.” Does it really make a difference what it is? Will you do anything differently?
- RyJones 8y ago
  I ask this question about metrics constantly. "If you had this information a year ago, what decisions would have been different?" It usually ends in dropping the request for another metric
- plink 8y ago
  Absolutely. So called "friendly" dolphins are often very sexually aggressive. With knowledge of what aquatic beast lurked in the depths below, I could tailor my preparedness to either be on guard against unwelcome mammalian advances, or remain blithely unconcerned over some incurious, nimrod fish.
nradov 8y ago
I understand your point, but let's dispel the myth of dangerous sharks. The vast majority of shark species never attack humans at all and it's totally safe to swim near them.

MereInterest 8y ago

* Choice A: X% chance of aggressive cancer, which worsens as it is left untreated. * Choice B: X% chance of finding and treating aggressive cancer. Y% chance of false positive leading to significant side effects. If Y is zero, then the choice to do further testing is obvious. If Y is large, then it depends on how large the side effects are, and what the chance of running into them is. You have risk in either case, and you will never reduce risk to zero. The question is how much risk you have, and what cost there is to mitigate that risk.

thebeefytaco 8y ago

Nope. When it comes to tumors, doctors always play 'better safe than sorry', but the treatments available for cancer are so detrimental that it's going to do way more harm than good to receive treatment for something that was benign. A little bit of information can be a dangerous thing.

rurp 8y ago

The issue is that testing often comes with its own health costs and many tests return a fairly high rate of false positives, which in turn leads to surgeries that can take a high toll on the body. Related to this, I recall reading about a study of elderly men with slow growing prostate cancer. Having surgery to remove the cancer did decrease the chance of dying from prostate cancer, but actually reduced their overall life expectancy. Prostate cancer surgery is hard on the body and an older person with a slow moving cancer has a pretty good chance of dying from some other cause before the cancer gets them.