7 ms·

This is the pertinent quote: > “Cancer screening was never really designed to increase longevity. Screenings are really designed to decrease premature deaths f

by kccqzy 3y ago

This is the pertinent quote: > “Cancer screening was never really designed to increase longevity. Screenings are really designed to decrease premature deaths from cancer.” Explained another way, Dahut said, if a person’s life expectancy at birth was 80, a cancer screening may prevent their premature death at 65, but it wouldn’t necessarily mean they’d live to be 90 instead of the predicted 80. Personally I think this is just a matter of terminology in public health not necessarily aligning with our intuitive understanding. I presume most people would think that preventing a shortening of lifespan is prolonging your life, but the article makes clear that they are different.

ekanes 3y ago
So they increase your lifespan probabilistically, but not in any terms you can measure. That said, the article's points about the costs of screening is valid and interesting. False negatives, false positives, time and money, those are absolutely real costs and worth taking into account.
Clent 3y ago
They are conflating cancer survival rates with longevity. When has someone claimed that treating cancer would increase life expectancy above the average? This is a dangerous article. People don't need more reasons to avoid cancer screenings.
- amanaplanacanal 3y ago
  It looks like they were comparing a group that got screening vs a group that didn’t get screening. If the group that got screening didn’t live longer than the group that didn’t get screening, that seems like a lot of wasted dollars.
  - throwway120385 3y ago
    Life expectancy is really only one dimension of "health," and it's probably the most shallow dimension. If I'm quadriplegic and confined to a ventilator but I live to 80, that's the same in this metric as if I'm not paralyzed and able to breathe on my own until I die. What if some people in the group that didn't get screening had fewer high-quality years? It might simply be that the last 5 years of life for people who are screened positive early on and who subsequently receive treatment is a better 5 years than the last 5 years of life for people who aren't screened positive early on and who subsequently have to undergo brutal hail mary treatments at the last minute.
    - pessimizer 3y ago
      > Life expectancy is really only one dimension of "health," and it's probably the most shallow dimension. If I'm quadriplegic and confined to a ventilator but I live to 80, that's the same in this metric as if I'm not paralyzed and able to breathe on my own until I die. Claiming that there are missing elements that could possibly turn the equation in favor of screening is cause for further research and analysis. You can't just claim that they fall in your favor; some diagnostic and exploratory processes due to false positives are painful and/or dangerous in and of themselves. > What if "What if" is right. You can't just conjure these people into existence to justify current policies, you have to find them and do the statistics.
      - throwway120385 3y ago
        Given that screening is arguably benign for most people, you could argue that we continue screening while we gather more information. But you do whatever you want to do. I'm just pointing out that it's really premature to cancel all of your screenings based on the idea that it doesn't add any years to your life. That may be true, but there's more to a life than how long you live.
        idopmstuff 3y ago
        > Given that screening is arguably benign for most people You're 100% wrong here, this is not a given. Prostate cancer screenings, which are very common, can have both false positives as well as findings of cancer that is and would remain completely benign. These can both lead to unnecessary treatments that cause serious negative health effects, including incontinence and erectile dysfunction. https://www.cdc.gov/cancer/prostate/basic_info/benefits-harms.htm https://www.cdc.gov/cancer/prostate/basic_info/benefits-harm...
        Gibbon1 3y ago
        Also read that death rates from thyroid cancer hasn't changed in 50 years. Despite huge numbers of thyroid screenings and treatment. An ultrasound of the thyroid often leads to finding a nodule. Which leads to a biopsy. Which comes out indeterminate. Which leads to a thyroidectomy and life long dependence on thyroid hormones. Another one is ductal carcinoma in situ. Read somewhere there is a 1% chance that will evolve into cancer. And yet you have women having double mastectomies and chemo for it.
  - DennisP 3y ago
    Yes but as someone else mentioned, it's like an insurance policy. Buying insurance doesn't make you richer on average, it makes the insurance company richer. But you aren't guaranteed the average outcome, so it's still rational to get the insurance, to cover the cases where you'd otherwise have a catastrophic loss. As with gambling, it's not just about expected value. You also have to consider risk of ruin.
    - pessimizer 3y ago
      False positives can be debilitating or fatal.
      - DennisP 3y ago
        But at what rate? The study doesn't say.
  - lowbloodsugar 3y ago
    FTA: "Overall cancer mortality worldwide has decreased significantly, falling 33% since 1991, in part due to early detection as well as advances in treatment and declines in smoking."
- rdedev 3y ago
  I think the consensus on cancer screening is stil not fully there? Came across this video by a cardiologist a long time ago https://youtu.be/yNzQ_sLGIuA?si=fUttSVFQjsrIqc-p https://youtu.be/yNzQ_sLGIuA?si=fUttSVFQjsrIqc-p I guess the main gist is that screening is not completely benign and a positive screen might lead to more interventions for what in the end could just be a benign tumor. Then there's the other point of detecting it late in life. Like treatment for cancer might not make much sense if you are already 89 years old
  - haltingproblem 3y ago
    This is the negative expectation part of most medical screening that most analyses miss. - Medical screenings themselves have iatrogenic effects, - the false positives interventions resulting from screenings have further negative effects and - finally the true positive interventions don't necessarily prolong life. All in all very difficult (confounding) tradeoffs that are impossible to quantify and understand especially when the cultural pressure is to do something.
    - arisAlexis 3y ago
      Do you really believe your third point? That most medical interventions for cancer do not prolong life? Or the word necessarily means your argument is null like "not all interventions prolong life". Yeah , we knew that already. It's never 100%.
      - NoZebra120vClip 3y ago
        I'd rather die of cancer than die of chemotherapy.
        newaccount74 3y ago
        A friend of mine had a pretty agressive cancer at age 16. He suffered through chemotherapy, a bone marrow transplant, and another round of chemo a year later. I think it sucked pretty bad. I visited him once in hospital, they made me wear a full body suit to prevent any infections. But that was 20 years ago. He lives a normal life now and has a family. I'm pretty sure chemo was worth it.
- aeturnum 3y ago
  Why would it be dangerous for people to avoid cancer screenings if those screenings do not impact life expectancy? You might want to know if you have cancer, but doesn't this suggest that...there's no baseline argument to suggest that all people undergo those screenings?
  - arisAlexis 3y ago
    They do impact life expectancy. The English language is a bit confusing to some mixed with statistics. They do not make life greater than average but they do make you closer to the average than if you die earlier.
glimshe 3y ago
If we are avoiding premature deaths for a subset of the population, wouldn't that by definition increase average life expectancy?
orblivion 3y ago
I mean, you could interpret that as "most cancer screenings don't extend life, because they come back negative". It's the "not most" case you're testing for in the first place.
- pessimizer 3y ago
  Not all positive tests are cancer. In some cases, actual cancers could be a tiny minority of positive tests. The tests themselves are a dangerous tool, and the way we minimize that danger is through statistics.
  - kccqzy 3y ago
    Then you are just changing one form of bad communication with another form. When a test indicates that there is cancer, the physician is not supposed to say "you have cancer" but rather "there is X% probability that you have cancer." If the test comes back negative, it should be "there is Y% probability that you have cancer" where presumably Y<X.
somenameforme 3y ago
The paper [1] is more well written and clear than the CNN article. They were comparing the aggregate life expectancies of people who went through regular screenings vs those who did not, and there was near zero difference except for colorectal screenings where the difference was about 4 months of difference. The paper is indeed presenting strong evidence that regular screenings have minimal value. [1] - https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2808648 https://jamanetwork.com/journals/jamainternalmedicine/fullar...
- hn_throwaway_99 3y ago
  Thanks for posting that. I read the article but not the paper, but I still feel like this may be a case where scientists "treat all time equally" in a way that most people do not, resulting in differing conclusions even though the data is the same. That is, putting aside monetary costs for the moment (which I know is not a good idea in reality, but want to focus on another issue), you often hear about how false positives cause "added anxiety and unnecessary treatments, which can cause harm", but if a breast cancer screening saves, say, lets one woman live until 80 instead of dying at 40, how many other people's "added anxiety" would it take to say "OK, that test was worth it". I think a lot of folks would go think that saving that life should be valued a lot more than just, say, comparing 40 years for her vs. time/anxiety "wasted" for false positives.
  - vc8f6vVV 3y ago
    X-ray is not just adding anxiety, it's harmful, and it's affecting all women who get screening, not only those who actually get cancer. Magic of numbers.
- francisofascii 3y ago
  > except for colorectal screenings where the difference was about 4 months of difference That sounds, uh, significant. So to clarify, does that mean people gain 4 months on average by getting this screening? Those who get the cancer gain years, and those that don't gain 0, so the average is 4 months?
kazinator 3y ago
If we decrease premature deaths from any cause, particularly a common cause of premature deaths, we increase life expectancy. Or just what do the authors think life expectancy means? It's an average. Every premature death drags down average life expectancy. If we say that cancer screening has no effect of life expectancy, that's exactly the same as saying that it doesn't prevent premature deaths. If cancer screening effectively prevents premature deaths, but the effect on the population's life expectancy is small, that effect is the wrong thing to be focusing on, potentially resulting in a harmful takeaway message.
- LorenPechtel 3y ago
  No, because we might be replacing one cause with another. That's what they've found with PSA--it kills (via treating things that wouldn't actually have killed the patient) as many as it saves.
  - kazinator 3y ago
    > That's what they've found with PSA--it kills (via treating things ...) I'm not sure what PSA you're referring to. The Prostate-Specific Antigen PSA is something secreted by the body, and not a treatment, so it can't be that one. Are you referring to overdiagnosis (via PSA or any other screening), resulting in overtreatment?
    - LorenPechtel 3y ago
      PSA is also commonly used to refer to the test that measures the PSA level. And, yes, it's treatment of things that weren't actually going to kill the patient. It's been known for quite a while that doing the test for screening produces no increase in life expectancy. What this study is saying is that the same problem seems to apply to most other cancer screenings.
- vc8f6vVV 3y ago
  You may be decreasing premature deaths from cancer but increasing premature deaths from other causes related to screening, thus you don't increase life expectancy. Read the original article in JAMA.
raverbashing 3y ago
Then the way this is being divulged is absolutely a very bad way Yes, life expectancy should count premature deaths Saying it "doesn't extend live" goes against that, because it absolutely does increase life expectancy Science communication is bad
teleforce 3y ago
There's only two things that are certain in this world, death and taxes - Benjamin Franklin. The main purpose of screening for early disease or genetic condition detection regardless of the diseases or illness, cancer, heart attack, stroke, etc, is not really to prolong longevity, even though that's a wonderful side effect, but the main thing to prevent complication(s) that may arise from the late detection. Apparently death does not incurs extra and massive medical bills, on the other hand complications will certainly do. If you connect the dots, this suddenly become a really good and plausible conspiracy theory. It's a shame that most of the health organizations, I'm looking at you American Heart Association (AHA), are really against any form of routine screening [1],[2]. [1] American Heart Association 14-Element Screening (Maron, BJ Circulation 2014): https://med.stanford.edu/content/dam/sm/ppc/documents/HSupervision/AHA_14-point.pdf https://med.stanford.edu/content/dam/sm/ppc/documents/HSuper... [2] ACC/AHA Release Recommendations For Congenital and Genetic Heart Disease Screenings in Youth: https://www.acc.org/latest-in-cardiology/articles/2014/09/15/14/24/acc-aha-release-recommendations-for-congenital-and-genetic-heart-disease-screenings-in-youth https://www.acc.org/latest-in-cardiology/articles/2014/09/15...
- vc8f6vVV 3y ago
  Just curious, have you read the original article in JAMA?
vc8f6vVV 3y ago
Have you read the original article, not the CNN interpretation? They are talking about harm vs benefits of screening. In simple words: you performed colonoscopy, got colon perforation and died of complications. Was colon cancer prevented? Absolutely! You didn't die of colon cancer! Is it any easier? No, it's not. The chance of dying of breast cancer is around 2.5%, so 1 women in 39 will die from that. OTOH annual X-rays affect the other 38 too, how many of them will die from X-ray exposure (which can cause e.g. another type of cancer, not necessary breast)? For the sake of discussion let's say 1 in 380. Congratulations, you've just increased breast cancer related death by 10%! Only it won't be in statistic as deaths from breast cancer.

by kccqzy 3y ago

ekanes 3y ago

So they increase your lifespan probabilistically, but not in any terms you can measure. That said, the article's points about the costs of screening is valid and interesting. False negatives, false positives, time and money, those are absolutely real costs and worth taking into account.

Clent 3y ago

They are conflating cancer survival rates with longevity. When has someone claimed that treating cancer would increase life expectancy above the average? This is a dangerous article. People don't need more reasons to avoid cancer screenings.

amanaplanacanal 3y ago
It looks like they were comparing a group that got screening vs a group that didn’t get screening. If the group that got screening didn’t live longer than the group that didn’t get screening, that seems like a lot of wasted dollars.
- throwway120385 3y ago
  Life expectancy is really only one dimension of "health," and it's probably the most shallow dimension. If I'm quadriplegic and confined to a ventilator but I live to 80, that's the same in this metric as if I'm not paralyzed and able to breathe on my own until I die. What if some people in the group that didn't get screening had fewer high-quality years? It might simply be that the last 5 years of life for people who are screened positive early on and who subsequently receive treatment is a better 5 years than the last 5 years of life for people who aren't screened positive early on and who subsequently have to undergo brutal hail mary treatments at the last minute.
  - pessimizer 3y ago
    > Life expectancy is really only one dimension of "health," and it's probably the most shallow dimension. If I'm quadriplegic and confined to a ventilator but I live to 80, that's the same in this metric as if I'm not paralyzed and able to breathe on my own until I die. Claiming that there are missing elements that could possibly turn the equation in favor of screening is cause for further research and analysis. You can't just claim that they fall in your favor; some diagnostic and exploratory processes due to false positives are painful and/or dangerous in and of themselves. > What if "What if" is right. You can't just conjure these people into existence to justify current policies, you have to find them and do the statistics.
    - throwway120385 3y ago
      Given that screening is arguably benign for most people, you could argue that we continue screening while we gather more information. But you do whatever you want to do. I'm just pointing out that it's really premature to cancel all of your screenings based on the idea that it doesn't add any years to your life. That may be true, but there's more to a life than how long you live.
      - idopmstuff 3y ago
        > Given that screening is arguably benign for most people You're 100% wrong here, this is not a given. Prostate cancer screenings, which are very common, can have both false positives as well as findings of cancer that is and would remain completely benign. These can both lead to unnecessary treatments that cause serious negative health effects, including incontinence and erectile dysfunction. https://www.cdc.gov/cancer/prostate/basic_info/benefits-harms.htm https://www.cdc.gov/cancer/prostate/basic_info/benefits-harm...
        Gibbon1 3y ago
        Also read that death rates from thyroid cancer hasn't changed in 50 years. Despite huge numbers of thyroid screenings and treatment. An ultrasound of the thyroid often leads to finding a nodule. Which leads to a biopsy. Which comes out indeterminate. Which leads to a thyroidectomy and life long dependence on thyroid hormones. Another one is ductal carcinoma in situ. Read somewhere there is a 1% chance that will evolve into cancer. And yet you have women having double mastectomies and chemo for it.
- DennisP 3y ago
  Yes but as someone else mentioned, it's like an insurance policy. Buying insurance doesn't make you richer on average, it makes the insurance company richer. But you aren't guaranteed the average outcome, so it's still rational to get the insurance, to cover the cases where you'd otherwise have a catastrophic loss. As with gambling, it's not just about expected value. You also have to consider risk of ruin.
  - pessimizer 3y ago
    False positives can be debilitating or fatal.
    - DennisP 3y ago
      But at what rate? The study doesn't say.
- lowbloodsugar 3y ago
  FTA: "Overall cancer mortality worldwide has decreased significantly, falling 33% since 1991, in part due to early detection as well as advances in treatment and declines in smoking."
rdedev 3y ago
I think the consensus on cancer screening is stil not fully there? Came across this video by a cardiologist a long time ago https://youtu.be/yNzQ_sLGIuA?si=fUttSVFQjsrIqc-p https://youtu.be/yNzQ_sLGIuA?si=fUttSVFQjsrIqc-p I guess the main gist is that screening is not completely benign and a positive screen might lead to more interventions for what in the end could just be a benign tumor. Then there's the other point of detecting it late in life. Like treatment for cancer might not make much sense if you are already 89 years old
- haltingproblem 3y ago
  This is the negative expectation part of most medical screening that most analyses miss. - Medical screenings themselves have iatrogenic effects, - the false positives interventions resulting from screenings have further negative effects and - finally the true positive interventions don't necessarily prolong life. All in all very difficult (confounding) tradeoffs that are impossible to quantify and understand especially when the cultural pressure is to do something.
  - arisAlexis 3y ago
    Do you really believe your third point? That most medical interventions for cancer do not prolong life? Or the word necessarily means your argument is null like "not all interventions prolong life". Yeah , we knew that already. It's never 100%.
    - NoZebra120vClip 3y ago
      I'd rather die of cancer than die of chemotherapy.
      - newaccount74 3y ago
        A friend of mine had a pretty agressive cancer at age 16. He suffered through chemotherapy, a bone marrow transplant, and another round of chemo a year later. I think it sucked pretty bad. I visited him once in hospital, they made me wear a full body suit to prevent any infections. But that was 20 years ago. He lives a normal life now and has a family. I'm pretty sure chemo was worth it.
aeturnum 3y ago
Why would it be dangerous for people to avoid cancer screenings if those screenings do not impact life expectancy? You might want to know if you have cancer, but doesn't this suggest that...there's no baseline argument to suggest that all people undergo those screenings?
- arisAlexis 3y ago
  They do impact life expectancy. The English language is a bit confusing to some mixed with statistics. They do not make life greater than average but they do make you closer to the average than if you die earlier.

glimshe 3y ago

If we are avoiding premature deaths for a subset of the population, wouldn't that by definition increase average life expectancy?

orblivion 3y ago

I mean, you could interpret that as "most cancer screenings don't extend life, because they come back negative". It's the "not most" case you're testing for in the first place.

pessimizer 3y ago
Not all positive tests are cancer. In some cases, actual cancers could be a tiny minority of positive tests. The tests themselves are a dangerous tool, and the way we minimize that danger is through statistics.
- kccqzy 3y ago
  Then you are just changing one form of bad communication with another form. When a test indicates that there is cancer, the physician is not supposed to say "you have cancer" but rather "there is X% probability that you have cancer." If the test comes back negative, it should be "there is Y% probability that you have cancer" where presumably Y<X.

somenameforme 3y ago

The paper [1] is more well written and clear than the CNN article. They were comparing the aggregate life expectancies of people who went through regular screenings vs those who did not, and there was near zero difference except for colorectal screenings where the difference was about 4 months of difference. The paper is indeed presenting strong evidence that regular screenings have minimal value. [1] - https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2808648 https://jamanetwork.com/journals/jamainternalmedicine/fullar...

hn_throwaway_99 3y ago
Thanks for posting that. I read the article but not the paper, but I still feel like this may be a case where scientists "treat all time equally" in a way that most people do not, resulting in differing conclusions even though the data is the same. That is, putting aside monetary costs for the moment (which I know is not a good idea in reality, but want to focus on another issue), you often hear about how false positives cause "added anxiety and unnecessary treatments, which can cause harm", but if a breast cancer screening saves, say, lets one woman live until 80 instead of dying at 40, how many other people's "added anxiety" would it take to say "OK, that test was worth it". I think a lot of folks would go think that saving that life should be valued a lot more than just, say, comparing 40 years for her vs. time/anxiety "wasted" for false positives.
- vc8f6vVV 3y ago
  X-ray is not just adding anxiety, it's harmful, and it's affecting all women who get screening, not only those who actually get cancer. Magic of numbers.
francisofascii 3y ago
> except for colorectal screenings where the difference was about 4 months of difference That sounds, uh, significant. So to clarify, does that mean people gain 4 months on average by getting this screening? Those who get the cancer gain years, and those that don't gain 0, so the average is 4 months?

kazinator 3y ago

If we decrease premature deaths from any cause, particularly a common cause of premature deaths, we increase life expectancy. Or just what do the authors think life expectancy means? It's an average. Every premature death drags down average life expectancy. If we say that cancer screening has no effect of life expectancy, that's exactly the same as saying that it doesn't prevent premature deaths. If cancer screening effectively prevents premature deaths, but the effect on the population's life expectancy is small, that effect is the wrong thing to be focusing on, potentially resulting in a harmful takeaway message.

LorenPechtel 3y ago
No, because we might be replacing one cause with another. That's what they've found with PSA--it kills (via treating things that wouldn't actually have killed the patient) as many as it saves.
- kazinator 3y ago
  > That's what they've found with PSA--it kills (via treating things ...) I'm not sure what PSA you're referring to. The Prostate-Specific Antigen PSA is something secreted by the body, and not a treatment, so it can't be that one. Are you referring to overdiagnosis (via PSA or any other screening), resulting in overtreatment?
  - LorenPechtel 3y ago
    PSA is also commonly used to refer to the test that measures the PSA level. And, yes, it's treatment of things that weren't actually going to kill the patient. It's been known for quite a while that doing the test for screening produces no increase in life expectancy. What this study is saying is that the same problem seems to apply to most other cancer screenings.
vc8f6vVV 3y ago
You may be decreasing premature deaths from cancer but increasing premature deaths from other causes related to screening, thus you don't increase life expectancy. Read the original article in JAMA.

raverbashing 3y ago

Then the way this is being divulged is absolutely a very bad way Yes, life expectancy should count premature deaths Saying it "doesn't extend live" goes against that, because it absolutely does increase life expectancy Science communication is bad

teleforce 3y ago

There's only two things that are certain in this world, death and taxes - Benjamin Franklin. The main purpose of screening for early disease or genetic condition detection regardless of the diseases or illness, cancer, heart attack, stroke, etc, is not really to prolong longevity, even though that's a wonderful side effect, but the main thing to prevent complication(s) that may arise from the late detection. Apparently death does not incurs extra and massive medical bills, on the other hand complications will certainly do. If you connect the dots, this suddenly become a really good and plausible conspiracy theory. It's a shame that most of the health organizations, I'm looking at you American Heart Association (AHA), are really against any form of routine screening [1],[2]. [1] American Heart Association 14-Element Screening (Maron, BJ Circulation 2014): https://med.stanford.edu/content/dam/sm/ppc/documents/HSupervision/AHA_14-point.pdf https://med.stanford.edu/content/dam/sm/ppc/documents/HSuper... [2] ACC/AHA Release Recommendations For Congenital and Genetic Heart Disease Screenings in Youth: https://www.acc.org/latest-in-cardiology/articles/2014/09/15/14/24/acc-aha-release-recommendations-for-congenital-and-genetic-heart-disease-screenings-in-youth https://www.acc.org/latest-in-cardiology/articles/2014/09/15...

vc8f6vVV 3y ago
Just curious, have you read the original article in JAMA?

vc8f6vVV 3y ago

Have you read the original article, not the CNN interpretation? They are talking about harm vs benefits of screening. In simple words: you performed colonoscopy, got colon perforation and died of complications. Was colon cancer prevented? Absolutely! You didn't die of colon cancer! Is it any easier? No, it's not. The chance of dying of breast cancer is around 2.5%, so 1 women in 39 will die from that. OTOH annual X-rays affect the other 38 too, how many of them will die from X-ray exposure (which can cause e.g. another type of cancer, not necessary breast)? For the sake of discussion let's say 1 in 380. Congratulations, you've just increased breast cancer related death by 10%! Only it won't be in statistic as deaths from breast cancer.