3 ms·

I've heard the same said of getting mammograms started earlier in life: they don't recommend it because the time spent chasing benign lumps is neither safe nor

by Dove 10y ago

I've heard the same said of getting mammograms started earlier in life: they don't recommend it because the time spent chasing benign lumps is neither safe nor efficient. This always seemed to me a terrible indictment of how medicine is practiced. Knowing that, do you have to chase down every lump your screening finds? Can you not consider the benefits of investigating further based on the dangers of doing so, the risk factors the patient has, maybe even what you see in successive scans over time? I am not a doctor, but there seems something unhealthy about a system in which you are advised to avoid learning information about yourself in order to avoid treatment.

highd 10y ago
I think you're exactly right - more frequent, less expensive testing means we have to change the criteria that mandates further investigation. One dilemma I've been thinking about recently is that there's an unfortunate burden put on care providers due to litigation that results in increased cost - the provider or radiologist that sees a "maybe" or a "shadow" on an image has to order a biopsy just to protect themselves from being sued on the off 1% chance that the thing becomes a serious health concern. In an environment where consumers evaluated their medicine based on value/$ they would be further dissuaded from a biopsy, but in America the nature of medical insurance disincentives this sort of cost analysis skepticism.
jeffdavis 10y ago
The incentives aren't aligned. A doctor who sees a lump and does nothing has a huge downside risk: it could be malignant and everyone will believe that the doctor is at fault. A doctor who orders the test will never be blamed for a fluke complication during a biopsy. It's hard to resolve becuse it's not even about money. It may be the doctor who is blaming himself.
- saalweachter 10y ago
  The doctor or the patient; if you're told that there is a lump (or seventeen) and it's probably nothing but you can get it checked out if you really want, most people will blame themselves if they don't get something checked out that later turns out to be something, and they know it.
  - Dove 10y ago
    That doesn't make sense to me. I have, many times in the last year, had a doctor say to me some variation on, "this isn't dangerous, but it could become so -- we'll keep an eye on it." So it's not that they can't act with sense and restraint with respect to risk. They clearly can. With respect to breast cancer specifically, they told me in school that finding it early improved your odds, and the earlier the better, and if you really wanted to do the right thing, you'd physically examine yourself looking for lumps on a monthly basis. That didn't seem unreasonable - and yet when something more accurate and objective is available, it's to be avoided out of a fear of unnecessary biopsies? Something strange is going on.
    - DanBC 10y ago
      > you'd physically examine yourself looking for lumps on a monthly basis. That's not the current advice. Current advice is that women become aware of what's normal for their breasts, and look for certain specific changes and not the vaguely described "lumps". http://www.nhs.uk/chq/pages/1740.aspx?CategoryID=60&SubCategoryID=182 http://www.nhs.uk/chq/pages/1740.aspx?CategoryID=60&SubCateg... > and yet when something more accurate and objective is available Is it more accurate? Mammograms are sensitive, but have a high false positive rate, especially for younger women. (All the sites I can find report sensitivity and false positive rates as percentages, which is a terrible way to report this information.) https://ww5.komen.org/BreastCancer/AccuracyofMammograms.html https://ww5.komen.org/BreastCancer/AccuracyofMammograms.html > Overall, the sensitivity of mammography is about 84 percent [9]. This means mammography correctly identifies about 84 percent of women who truly have breast cancer. > The more mammograms a woman has, the more likely she will have a false positive result that will require follow-up tests. The chance of having a false positive result after 10 yearly mammograms is about 50-60 percent [22-24]. http://www.breastcancer.org/symptoms/understand_bc/statistics http://www.breastcancer.org/symptoms/understand_bc/statistic... > In 2017, an estimated 255,180 new cases of invasive breast cancer are expected to be diagnosed in women in the U.S., along with 63,410 new cases of non-invasive (in situ) breast cancer. Ann, a 45 year old woman, goes for a mammogram. It returns a positive result. What are the chances that Ann has breast cancer? (Scarily lots of doctors can't answer this question if the information is presented as percentages. See Gerd Gigerenzer's book Reckoning with risk for many examples.) https://www.cancer.gov/types/breast/hp/breast-screening-pdq https://www.cancer.gov/types/breast/hp/breast-screening-pdq > Magnitude of Effect: In the randomized controlled trials (RCTs), for women aged 40 to 74 years, screening with mammography has been associated with a 15% to 20% relative reduction in mortality from breast cancer.[1] Absolute mortality benefit for women screened annually for 10 years is approximately 1% overall, ranging from 4 per 10,000 women who start screening at age 40 years to 50 per 10,000 women who start at age 50 years.[2] Based on the 25-year follow-up from the Canadian National Breast Screening Study (CNBSS), an RCT of breast cancer screening,[3] there is some uncertainty about the magnitude of benefit of mammography in the present day.
lomnakkus 10y ago
> Knowing that, do you have to chase down every lump your screening finds? Can you not consider the benefits of investigating further based on the dangers of doing so, The problem is this: How do you when to investigate further and when not to? Unless you can come up with a way to make that choice without just rolling dice, you're not really doing any better. > ... the risk factors the patient has, maybe even what you see in successive scans over time? Aside from perverse incentives as mentioned by someone else, there may also be a risk from the scan itself (as in breast cancer screening, e.g.). There's also secondary effects from a positive scan like anxiety before being able to confirm or reject a diagnosis -- this has known health effects. The confirmation itself may have associated risks, etc. It's far from clear that the benefits outweigh the risks[1], so it seems like overkill to call this an indictment of medicine. (I should also add that in e.g. breast cancer women who are known to be at risk -- there's specific genes which carry very high risk (BRCA1, BRCA2) and other genetic factors with high penetrance.) [1] This is also something that many in the medical profession acknowledge, see for example [2] where there's a load of material on breast cancer, specifically. [2] http://sciencebasedmedicine.org/tag/mammography/ http://sciencebasedmedicine.org/tag/mammography/

by Dove 10y ago

highd 10y ago

I think you're exactly right - more frequent, less expensive testing means we have to change the criteria that mandates further investigation. One dilemma I've been thinking about recently is that there's an unfortunate burden put on care providers due to litigation that results in increased cost - the provider or radiologist that sees a "maybe" or a "shadow" on an image has to order a biopsy just to protect themselves from being sued on the off 1% chance that the thing becomes a serious health concern. In an environment where consumers evaluated their medicine based on value/$ they would be further dissuaded from a biopsy, but in America the nature of medical insurance disincentives this sort of cost analysis skepticism.

jeffdavis 10y ago

The incentives aren't aligned. A doctor who sees a lump and does nothing has a huge downside risk: it could be malignant and everyone will believe that the doctor is at fault. A doctor who orders the test will never be blamed for a fluke complication during a biopsy. It's hard to resolve becuse it's not even about money. It may be the doctor who is blaming himself.

saalweachter 10y ago
The doctor or the patient; if you're told that there is a lump (or seventeen) and it's probably nothing but you can get it checked out if you really want, most people will blame themselves if they don't get something checked out that later turns out to be something, and they know it.
- Dove 10y ago
  That doesn't make sense to me. I have, many times in the last year, had a doctor say to me some variation on, "this isn't dangerous, but it could become so -- we'll keep an eye on it." So it's not that they can't act with sense and restraint with respect to risk. They clearly can. With respect to breast cancer specifically, they told me in school that finding it early improved your odds, and the earlier the better, and if you really wanted to do the right thing, you'd physically examine yourself looking for lumps on a monthly basis. That didn't seem unreasonable - and yet when something more accurate and objective is available, it's to be avoided out of a fear of unnecessary biopsies? Something strange is going on.
  - DanBC 10y ago
    > you'd physically examine yourself looking for lumps on a monthly basis. That's not the current advice. Current advice is that women become aware of what's normal for their breasts, and look for certain specific changes and not the vaguely described "lumps". http://www.nhs.uk/chq/pages/1740.aspx?CategoryID=60&SubCategoryID=182 http://www.nhs.uk/chq/pages/1740.aspx?CategoryID=60&SubCateg... > and yet when something more accurate and objective is available Is it more accurate? Mammograms are sensitive, but have a high false positive rate, especially for younger women. (All the sites I can find report sensitivity and false positive rates as percentages, which is a terrible way to report this information.) https://ww5.komen.org/BreastCancer/AccuracyofMammograms.html https://ww5.komen.org/BreastCancer/AccuracyofMammograms.html > Overall, the sensitivity of mammography is about 84 percent [9]. This means mammography correctly identifies about 84 percent of women who truly have breast cancer. > The more mammograms a woman has, the more likely she will have a false positive result that will require follow-up tests. The chance of having a false positive result after 10 yearly mammograms is about 50-60 percent [22-24]. http://www.breastcancer.org/symptoms/understand_bc/statistics http://www.breastcancer.org/symptoms/understand_bc/statistic... > In 2017, an estimated 255,180 new cases of invasive breast cancer are expected to be diagnosed in women in the U.S., along with 63,410 new cases of non-invasive (in situ) breast cancer. Ann, a 45 year old woman, goes for a mammogram. It returns a positive result. What are the chances that Ann has breast cancer? (Scarily lots of doctors can't answer this question if the information is presented as percentages. See Gerd Gigerenzer's book Reckoning with risk for many examples.) https://www.cancer.gov/types/breast/hp/breast-screening-pdq https://www.cancer.gov/types/breast/hp/breast-screening-pdq > Magnitude of Effect: In the randomized controlled trials (RCTs), for women aged 40 to 74 years, screening with mammography has been associated with a 15% to 20% relative reduction in mortality from breast cancer.[1] Absolute mortality benefit for women screened annually for 10 years is approximately 1% overall, ranging from 4 per 10,000 women who start screening at age 40 years to 50 per 10,000 women who start at age 50 years.[2] Based on the 25-year follow-up from the Canadian National Breast Screening Study (CNBSS), an RCT of breast cancer screening,[3] there is some uncertainty about the magnitude of benefit of mammography in the present day.

lomnakkus 10y ago

> Knowing that, do you have to chase down every lump your screening finds? Can you not consider the benefits of investigating further based on the dangers of doing so, The problem is this: How do you when to investigate further and when not to? Unless you can come up with a way to make that choice without just rolling dice, you're not really doing any better. > ... the risk factors the patient has, maybe even what you see in successive scans over time? Aside from perverse incentives as mentioned by someone else, there may also be a risk from the scan itself (as in breast cancer screening, e.g.). There's also secondary effects from a positive scan like anxiety before being able to confirm or reject a diagnosis -- this has known health effects. The confirmation itself may have associated risks, etc. It's far from clear that the benefits outweigh the risks[1], so it seems like overkill to call this an indictment of medicine. (I should also add that in e.g. breast cancer women who are known to be at risk -- there's specific genes which carry very high risk (BRCA1, BRCA2) and other genetic factors with high penetrance.) [1] This is also something that many in the medical profession acknowledge, see for example [2] where there's a load of material on breast cancer, specifically. [2] http://sciencebasedmedicine.org/tag/mammography/ http://sciencebasedmedicine.org/tag/mammography/