4 ms·

My doctor recommended Cologuard, a test of your stool sample for cancerous DNA, instead of a colonoscopy. I can't imagine taking a colonoscopy now.

nwellinghoff 3y ago
Colonoscopy has a big advantage in that they are already in there. If they see anything forming that is pre-cancerous they can take it out before it turns into a problem that would show up on a Cologuard test.
- gcheong 3y ago
  But that’s also highly dependent on how good the doctor is at finding the problems. Apparently doctors in the US find precancerous polyps 40% of the time according to the article. That may not be so great given the time between screenings (ten years) if one is missed.
  - iaseiadit 3y ago
    It’s great if you’re in the 40%.
- raverbashing 3y ago
  And the big disadvantage that to get there your need to book 2 professionals (?) and take pretty much one day off, and there are risks associated with anesthesia and the procedure itself I don't think it scales (Not to mention the interests of doctors of suggesting things that make them more money) Edit: now I see TFA mentions risk of perforation and that the risk is smaller without anesthesia
  - ghaff 3y ago
    Well, in the US, they're following normal protocol. It would probably be irresponsible for them to try to dissuade you from a colonoscopy. But, yes, it's a day involving a gastroenterologist, typically an anesthesiologist, nurses presumably, and someone to take to back and forth from the procedure. It's definitely not standard lab work.
  - amrocha 3y ago
    In Japan, everyone over 40 gets yearly colonoscopies as part of a general health check up. That should be a really good source of data, someone should take a look at that. But what I was getting at is that it can scale.
    - gcheong 3y ago
      Source? Yearly colonoscopies sound dubious - my google search results said they use fecal occult blood tests yearly with a follow-up colonoscopy if you test positive which sounds more reasonable to me.
      - amrocha 3y ago
        The source is that I live here and everyone talks about it. Poop tests are for everyone over 30
    - greedo 3y ago
      Yearly? That's crazy. I had yearly colos AFTER I had rectal cancer, but now I'm on the 10 year plan. I can't see yearly being both cost-effective and safe.
  - maroonblazer 3y ago
    You also need to find someone to transport you to/from the procedure. I moved to a new city and didn't know anyone. I was told to get a colonoscopy for no other reason than I was 50. There was literally no one I could ask to take off half a weekday to accompany me. Ended up doing the FIT test (stool sample) instead (and once/year thereafter) and 6 years on still haven't had a colonoscopy.
- IshKebab 3y ago
  *small advantage (according to this study).
stouset 3y ago
Cologuard has a significantly high false positive rate, as far as I’m aware.
- huytersd 3y ago
  False positives are bad but not disastrous. How bad are the false negatives?
  - matheusmoreira 3y ago
    Manufacturer claims around 8% false negatives, 92%-94% sensitivity, 87%-90% specificity and 99.94% negative predictive value. Published study: https://pubmed.ncbi.nlm.nih.gov/24645800/ https://pubmed.ncbi.nlm.nih.gov/24645800/ It appears they calculated the negative predictive value based on the population sample of that study. It may differ significantly from the negative predictive value for the general population.
- matheusmoreira 3y ago
  All screening tests do. In general, cancer screening employs highly sensitive tests which are supposed to react to anything that even remotely looks like cancer. Negative results are relatively trustworthy while positive results justify further testing with more specific tests which may be more risky, more expensive or both. Colonoscopy is an example of a test that is both expensive and risky.
- fsckboy 3y ago
  does a cologuard false positive indicate a colonoscopy? if so, as long as the false negatives aren't substantially worse, it sounds like a win.
  - bluGill 3y ago
    Yes. If it finds anything you get called very high risk and get right in. My doctor sent me to cologuard because the people doing colonoscopies had a year long waiting list, I don't need to get in, but if the test found something they would let me skip the line and i'd be in a few weeks later. Since it didn't i'm not in line at all, but I need a new test in three years, while the colonoscopie is good for ten.

nwellinghoff 3y ago

Colonoscopy has a big advantage in that they are already in there. If they see anything forming that is pre-cancerous they can take it out before it turns into a problem that would show up on a Cologuard test.

gcheong 3y ago
But that’s also highly dependent on how good the doctor is at finding the problems. Apparently doctors in the US find precancerous polyps 40% of the time according to the article. That may not be so great given the time between screenings (ten years) if one is missed.
- iaseiadit 3y ago
  It’s great if you’re in the 40%.
raverbashing 3y ago
And the big disadvantage that to get there your need to book 2 professionals (?) and take pretty much one day off, and there are risks associated with anesthesia and the procedure itself I don't think it scales (Not to mention the interests of doctors of suggesting things that make them more money) Edit: now I see TFA mentions risk of perforation and that the risk is smaller without anesthesia
- ghaff 3y ago
  Well, in the US, they're following normal protocol. It would probably be irresponsible for them to try to dissuade you from a colonoscopy. But, yes, it's a day involving a gastroenterologist, typically an anesthesiologist, nurses presumably, and someone to take to back and forth from the procedure. It's definitely not standard lab work.
- amrocha 3y ago
  In Japan, everyone over 40 gets yearly colonoscopies as part of a general health check up. That should be a really good source of data, someone should take a look at that. But what I was getting at is that it can scale.
  - gcheong 3y ago
    Source? Yearly colonoscopies sound dubious - my google search results said they use fecal occult blood tests yearly with a follow-up colonoscopy if you test positive which sounds more reasonable to me.
    - amrocha 3y ago
      The source is that I live here and everyone talks about it. Poop tests are for everyone over 30
  - greedo 3y ago
    Yearly? That's crazy. I had yearly colos AFTER I had rectal cancer, but now I'm on the 10 year plan. I can't see yearly being both cost-effective and safe.
- maroonblazer 3y ago
  You also need to find someone to transport you to/from the procedure. I moved to a new city and didn't know anyone. I was told to get a colonoscopy for no other reason than I was 50. There was literally no one I could ask to take off half a weekday to accompany me. Ended up doing the FIT test (stool sample) instead (and once/year thereafter) and 6 years on still haven't had a colonoscopy.
IshKebab 3y ago
*small advantage (according to this study).

stouset 3y ago

Cologuard has a significantly high false positive rate, as far as I’m aware.

huytersd 3y ago
False positives are bad but not disastrous. How bad are the false negatives?
- matheusmoreira 3y ago
  Manufacturer claims around 8% false negatives, 92%-94% sensitivity, 87%-90% specificity and 99.94% negative predictive value. Published study: https://pubmed.ncbi.nlm.nih.gov/24645800/ https://pubmed.ncbi.nlm.nih.gov/24645800/ It appears they calculated the negative predictive value based on the population sample of that study. It may differ significantly from the negative predictive value for the general population.
matheusmoreira 3y ago
All screening tests do. In general, cancer screening employs highly sensitive tests which are supposed to react to anything that even remotely looks like cancer. Negative results are relatively trustworthy while positive results justify further testing with more specific tests which may be more risky, more expensive or both. Colonoscopy is an example of a test that is both expensive and risky.
fsckboy 3y ago
does a cologuard false positive indicate a colonoscopy? if so, as long as the false negatives aren't substantially worse, it sounds like a win.
- bluGill 3y ago
  Yes. If it finds anything you get called very high risk and get right in. My doctor sent me to cologuard because the people doing colonoscopies had a year long waiting list, I don't need to get in, but if the test found something they would let me skip the line and i'd be in a few weeks later. Since it didn't i'm not in line at all, but I need a new test in three years, while the colonoscopie is good for ten.