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We could greatly increase the survival for most cancers if we could detect them much earlier. “ If it is caught in the early stages then the chances of surviva

We could greatly increase the survival for most cancers if we could detect them much earlier. “ If it is caught in the early stages then the chances of survival are good, but as the cancer becomes more aggressive and spreads throughout the body (known as metastatic cancer) then survival plummets” Craig Venter: https://youtu.be/iUqgTYbkHP8?t=15m37s https://youtu.be/iUqgTYbkHP8?t=15m37s

toomuchtodo 7y ago
How do we detect it earlier? And how do you scale that up?
- akiselev 7y ago
  We need tests with lower false positive rates. The problem with catching cancer early is confirming whether you actually have cancer or not. This most often requires invasive biopsies which exposes the patient to significant postop risks and the early detection tests' false positive rates mean that blanket tests of all patients would do far more harm than good. For example, mammograms have a false positive rate of something like 50% and complications happen in something like 30% of surgeries. Multiply that by every possible common cancer and you've got a no-win scenario. All of our early detection tools are pretty terrible and we can't ethically test everyone for everything so it's all about educating the patients to take a proactive role.
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  - afarrell 7y ago
    > mammograms have a false positive rate of something like 50% This is pretty astounding to me. Where should I read more about this?
    - deleted 7y ago
      [deleted]
    - adventured 7y ago
      The 50-60% figure is based on ten annual mammograms. In a given mammogram it's more like 7-12%. The younger you are, the more likely your positive result will be a false positive. And it also varies based on tissue density (women with more dense breasts have higher false positive rates). The higher false positive rate in younger women is of course why they've shifted screening times, pushing back the suggested start age and or doing every other year instead of every year.
      - toomuchtodo 7y ago
        Digital imaging also has a higher FP rate than film.
      - riahi 7y ago
        It’s also in how you define a false positive... If you recall someone from screening for additional diagnostic views, this is not strictly a false positive as the initial evaluation is definitionally incomplete. However, many would argue the additional views result in additional patient stress and anxiety (I personally do not buy this argument especially if you set expectations at the time of initial image acquisition). Of the patients who are recalled, maybe 20% proceed to biopsy, of which probably 20% have histologic cancer and another percentage have high risk lesions that are not cancerous per se but are often surgically removed as they either cannot be fully sampled using a minimally invasive technique. Recall rates are tracked and heavily scrutinized at the individual radiologist level. The targeted recall rate is in the range of 5-10% with the assumption that recalling more than this is being too sensitive and less than this is potentially missing cancer. Mammography performance is often defined in cancers per 1000 screening exams for a given population. Realistically, someone needs to proceed to all the way to biopsy (and have it come back negative) to have a real false positive. Someone being recalled from screening for additional views only to be released as “superimposed tissue” or “benign finding” is not a true false positive. To argue so is being a bit disingenuous.
  - astura 7y ago
    >We need tests with lower false positive rates. The problem with catching cancer early is confirming whether you actually have cancer or not. This is a big problem, but it's far from the only problem. The other problem is catching cancers that are destined to stay harmlessly in place. So-called "turtles." They are surprisingly common among the population. South Korea currently has this problem - 15 years of screening has found a massive amount of thyroid cancer, so much so that thyroid cancer is now the most common cancer in Korea. Yet all these extra cancers discovered and treated early hasn't reduced the death rate at all. That means the cancers being detected and treated are destined to have no negative consequences to the patient. https://www.npr.org/sections/health-shots/2017/05/09/527569291/dont-screen-for-thyroid-cancer-task-force-says https://www.npr.org/sections/health-shots/2017/05/09/5275692...
legulere 7y ago
The negative side effect is that if you catch cancer in earlier stages you also catch more cancers that would not reach later stages.
- amelius 7y ago
  But the question is: is that a real problem? Would it make preventive screening useless?
  - mtts 7y ago
    Yes. Cancer treatment is very, very invasive.
  - jghn 7y ago
    Yes, it is a real problem. Cancer treatment is generally not a walk in the park, and you'd be administering it to people who never would have otherwise need it. Imagine having portions of your body removed and/or receiving brutal treatment for no real purpose. Further, these tests have false positives and even in the best case that could cause undue stress and strain. It's been a while since I've been in the field, but at least as of several years ago the oncologists I knew were starting to turn against heavy pushes for early screening for these and similar reasons.
    - melling 7y ago
      Would you treat cancers that are caught 2-3 years earlier any differently? Along with better early detection, aren’t we trying to increase the tests’ accuracy? If we have 2-3 additional years to monitor and treat a cancer, we have more options.
      - lukeschlather 7y ago
        My understanding is most people get cancer cells regularly. Possibly every day. The immune system clears them out naturally. The question is how old is a cancer before it becomes a threat worthy of analysis. Obviously one cell is probably not interesting. I think there's evidence even cancers that are large enough to be visible to the naked eye are not typically dangerous. If 99% are harmless, what is the point in early detection? It's an expensive test and expensive doctors visits to mitigate a 1% risk. It's interesting from a research perspective to be sure, but not as a standard of care.
astura 7y ago
That was the conventional wisdom for years and it seems obviously true - catch cancer early before it spreads. Yet when we actually study these things we find out early detection might not be desirable (but also sometimes is). It's complicated and there's a whole lot we don't know. Also "most cancers" is almost certainly false, more like "some cancers." And at what cost? https://fivethirtyeight.com/features/the-case-against-early-cancer-detection/ https://fivethirtyeight.com/features/the-case-against-early-... >It’s hard to believe in overdiagnosis and overtreatment if you imagine that cancer behaves in a progressive manner: that is, that it arises from one haywire cell that replicates abnormally before inevitably spreading to other parts of the body, eventually killing the person. Let’s call this way of thinking the relentless progression model. In this model, every cancer cell is destined to spread and become lethal, and that’s how doctors have traditionally been taught to think of cancer’s progression. >Today, thanks to sophisticated cancer genetics and advances in tumor biology, we know that’s not always how it works. Cancer is not a single disease; it’s many. On one end of the spectrum lie cancers that become aggressive and invasive from the start, and on the other end are cancers that remain non-invasive and therefore harmless. Whether a single rogue cell replicates slowly and stays put or goes wild and spreads is determined by a variety of factors that scientists are still working to understand. >What’s clear is that cancers fall into a few general behavior patterns, which Welch and others have compared to animals that must be kept in the barnyard to prevent a deadly rampage. Papillary tumors are like turtles — they move very slowly and never pose an escape risk. They don’t need screening, because they will never cause trouble. Then there are rabbits, which are eager to hop away to other parts of the body, but can be confined if they’re found and fenced. These are the cancers that can be helped by early detection and treatment. Birds, on the other hand, are so flighty and quick that they can’t be confined. Screening makes no difference for bird cancers, because they’re so aggressive that they can’t be detected before they’ve begun their deadly course. >No cancer screening has ever eliminated the majority of cancer deaths. Instead, the best screening can do is reign in the rabbits. Birds remain unstoppable, and they’re the ones responsible for most cancer deaths. This is why, Welch says, three decades of mammography have failed to put a dent in the rate of women presenting with metastatic breast cancer upon their initial diagnosis. See also: https://sciencebasedmedicine.org/a-skeptical-look-at-screening-tests/ https://sciencebasedmedicine.org/a-skeptical-look-at-screeni... https://www.wbur.org/commonhealth/2017/06/08/cancer-diagnosis-wealthy https://www.wbur.org/commonhealth/2017/06/08/cancer-diagnosi...

toomuchtodo 7y ago

How do we detect it earlier? And how do you scale that up?

akiselev 7y ago
We need tests with lower false positive rates. The problem with catching cancer early is confirming whether you actually have cancer or not. This most often requires invasive biopsies which exposes the patient to significant postop risks and the early detection tests' false positive rates mean that blanket tests of all patients would do far more harm than good. For example, mammograms have a false positive rate of something like 50% and complications happen in something like 30% of surgeries. Multiply that by every possible common cancer and you've got a no-win scenario. All of our early detection tools are pretty terrible and we can't ethically test everyone for everything so it's all about educating the patients to take a proactive role.
- deleted 7y ago
  [deleted]
- deleted 7y ago
  [deleted]
- afarrell 7y ago
  > mammograms have a false positive rate of something like 50% This is pretty astounding to me. Where should I read more about this?
  - deleted 7y ago
    [deleted]
  - adventured 7y ago
    The 50-60% figure is based on ten annual mammograms. In a given mammogram it's more like 7-12%. The younger you are, the more likely your positive result will be a false positive. And it also varies based on tissue density (women with more dense breasts have higher false positive rates). The higher false positive rate in younger women is of course why they've shifted screening times, pushing back the suggested start age and or doing every other year instead of every year.
    - toomuchtodo 7y ago
      Digital imaging also has a higher FP rate than film.
    - riahi 7y ago
      It’s also in how you define a false positive... If you recall someone from screening for additional diagnostic views, this is not strictly a false positive as the initial evaluation is definitionally incomplete. However, many would argue the additional views result in additional patient stress and anxiety (I personally do not buy this argument especially if you set expectations at the time of initial image acquisition). Of the patients who are recalled, maybe 20% proceed to biopsy, of which probably 20% have histologic cancer and another percentage have high risk lesions that are not cancerous per se but are often surgically removed as they either cannot be fully sampled using a minimally invasive technique. Recall rates are tracked and heavily scrutinized at the individual radiologist level. The targeted recall rate is in the range of 5-10% with the assumption that recalling more than this is being too sensitive and less than this is potentially missing cancer. Mammography performance is often defined in cancers per 1000 screening exams for a given population. Realistically, someone needs to proceed to all the way to biopsy (and have it come back negative) to have a real false positive. Someone being recalled from screening for additional views only to be released as “superimposed tissue” or “benign finding” is not a true false positive. To argue so is being a bit disingenuous.
- astura 7y ago
  >We need tests with lower false positive rates. The problem with catching cancer early is confirming whether you actually have cancer or not. This is a big problem, but it's far from the only problem. The other problem is catching cancers that are destined to stay harmlessly in place. So-called "turtles." They are surprisingly common among the population. South Korea currently has this problem - 15 years of screening has found a massive amount of thyroid cancer, so much so that thyroid cancer is now the most common cancer in Korea. Yet all these extra cancers discovered and treated early hasn't reduced the death rate at all. That means the cancers being detected and treated are destined to have no negative consequences to the patient. https://www.npr.org/sections/health-shots/2017/05/09/527569291/dont-screen-for-thyroid-cancer-task-force-says https://www.npr.org/sections/health-shots/2017/05/09/5275692...

legulere 7y ago

The negative side effect is that if you catch cancer in earlier stages you also catch more cancers that would not reach later stages.

amelius 7y ago
But the question is: is that a real problem? Would it make preventive screening useless?
- mtts 7y ago
  Yes. Cancer treatment is very, very invasive.
- jghn 7y ago
  Yes, it is a real problem. Cancer treatment is generally not a walk in the park, and you'd be administering it to people who never would have otherwise need it. Imagine having portions of your body removed and/or receiving brutal treatment for no real purpose. Further, these tests have false positives and even in the best case that could cause undue stress and strain. It's been a while since I've been in the field, but at least as of several years ago the oncologists I knew were starting to turn against heavy pushes for early screening for these and similar reasons.
  - melling 7y ago
    Would you treat cancers that are caught 2-3 years earlier any differently? Along with better early detection, aren’t we trying to increase the tests’ accuracy? If we have 2-3 additional years to monitor and treat a cancer, we have more options.
    - lukeschlather 7y ago
      My understanding is most people get cancer cells regularly. Possibly every day. The immune system clears them out naturally. The question is how old is a cancer before it becomes a threat worthy of analysis. Obviously one cell is probably not interesting. I think there's evidence even cancers that are large enough to be visible to the naked eye are not typically dangerous. If 99% are harmless, what is the point in early detection? It's an expensive test and expensive doctors visits to mitigate a 1% risk. It's interesting from a research perspective to be sure, but not as a standard of care.

astura 7y ago

That was the conventional wisdom for years and it seems obviously true - catch cancer early before it spreads. Yet when we actually study these things we find out early detection might not be desirable (but also sometimes is). It's complicated and there's a whole lot we don't know. Also "most cancers" is almost certainly false, more like "some cancers." And at what cost? https://fivethirtyeight.com/features/the-case-against-early-cancer-detection/ https://fivethirtyeight.com/features/the-case-against-early-... >It’s hard to believe in overdiagnosis and overtreatment if you imagine that cancer behaves in a progressive manner: that is, that it arises from one haywire cell that replicates abnormally before inevitably spreading to other parts of the body, eventually killing the person. Let’s call this way of thinking the relentless progression model. In this model, every cancer cell is destined to spread and become lethal, and that’s how doctors have traditionally been taught to think of cancer’s progression. >Today, thanks to sophisticated cancer genetics and advances in tumor biology, we know that’s not always how it works. Cancer is not a single disease; it’s many. On one end of the spectrum lie cancers that become aggressive and invasive from the start, and on the other end are cancers that remain non-invasive and therefore harmless. Whether a single rogue cell replicates slowly and stays put or goes wild and spreads is determined by a variety of factors that scientists are still working to understand. >What’s clear is that cancers fall into a few general behavior patterns, which Welch and others have compared to animals that must be kept in the barnyard to prevent a deadly rampage. Papillary tumors are like turtles — they move very slowly and never pose an escape risk. They don’t need screening, because they will never cause trouble. Then there are rabbits, which are eager to hop away to other parts of the body, but can be confined if they’re found and fenced. These are the cancers that can be helped by early detection and treatment. Birds, on the other hand, are so flighty and quick that they can’t be confined. Screening makes no difference for bird cancers, because they’re so aggressive that they can’t be detected before they’ve begun their deadly course. >No cancer screening has ever eliminated the majority of cancer deaths. Instead, the best screening can do is reign in the rabbits. Birds remain unstoppable, and they’re the ones responsible for most cancer deaths. This is why, Welch says, three decades of mammography have failed to put a dent in the rate of women presenting with metastatic breast cancer upon their initial diagnosis. See also: https://sciencebasedmedicine.org/a-skeptical-look-at-screening-tests/ https://sciencebasedmedicine.org/a-skeptical-look-at-screeni... https://www.wbur.org/commonhealth/2017/06/08/cancer-diagnosis-wealthy https://www.wbur.org/commonhealth/2017/06/08/cancer-diagnosi...