4 ms·

MD here. It's "not done" because it could hurt you. Here's the Bayesian argument: - Let's assume a lab test (or imaging test) has a 1% false positive rate and

• asdf21 7y ago
  This would also force advancements in the field re: distinguishing false positives. More information is better than less, imo.
  • Waterluvian 7y ago
    False positives can be actively harmful. Unnecessary biopsies lead to unnecessary infections and stress and such.
    • nostromo 7y ago
      Cancer is also harmful, particularly if not found early.
      • SketchySeaBeast 7y ago
        I assume every doctor's visit sees you getting checked for every type of condition every time, or do you want your doctor to play the odds and only look for things you're likely to have? There's plenty of harmful ways to die, and you'll find they don't check for most of them until they have a decent reason.
  • dannykwells 7y ago
    No, this is the wrong argument. What would happen is, eventually people just wouldn't believe any of these tests and they would become useless, even when they did reach a high level of PPV. Also see the point about biopsies - definitely not non-invasive, often require surgery. Also cost - you're now looking at 5-10k extra charges.
• docker_up 7y ago
  Maybe figure out a better way to verify that doesn't require biopsy? Maybe use machine learning in conjunction with better data? I don't know enough but there must be other techniques we could devise that don't require major invasive surgery every single time. Just sitting on our hands on this information and letting people die is the worst decision. We need to improve our technology to get better results, not throw our hands up in the air and say the problem is too hard.
  • Nasrudith 7y ago
    Well the ways that don't involve surgery are themselves less accurate heuristics with false positives. How can they calibrate without being certain if it is a true or false positive or negative? Better imaging is an option but that often falls into dangerous in itself or easier said than done like say trying to do detection of cancer by scent. Machine learning is fundamentally GIGO and tends to learn smartass shortcuts if one isn't careful. "The healthy sample data is less zoomed in while the cancer ones are zoomed in - therefore full chest x-ray is fine but a lung X-ray is cancer."
    • docker_up 7y ago
      This type of attitude is typical, where one likes to dismiss new ideas and keep status quo instead of coming up with new ideas or innovations. The point is that there is an opportunity for the Steve Jobs of health care to come up with a way, a new innovative novel way, for classification of tumors to be improved without needing biopsy. Once we have that, then we can take tests to our heart's content. Right now, the attitude of "we shouldn't have people take tests and detect cancer early because our current method of determining if they are cancerous would make it too hard" isn't acceptable.
      • skybrian 7y ago
        Presumably none of us here are inventors of new medical technology. We are just amateurs talking about this casually on Hacker News. Saying it's "unacceptable" doesn't change anything from either the doctor or patient's point of view. Until the new tech comes along, we need to accept the limitations of what we have now.
• phkahler 7y ago
  Wouldn't there also be risk from injecting radioactive tracers? And of course any CT radiation.
• sershe 7y ago
  Would re-screening everyone positive N weeks after the first positive, and then re-screening the new positives again N weeks later, alleviate this (absent other symptoms)? I'm assuming here a growing cancer is easier to detect over time.