Nip future cancer in the bud
November 10, 2010 2:58 PM Subscribe
Is there such a thing as a generic cancer screening?
If such a thing doesn't exist, it seems like it would be a worthwhile endeavor since:
1. All cancers are detectable in one manner or another
2. The earlier a cancer is detected, the higher the chance of survival
3. Late-stage cancer treatment is incredibly expensive
What's the closest, and least expensive, procedure(s) someone can have annually (or every two years) that would give them a relative leg up on any potential cancers?
If such a thing doesn't exist, it seems like it would be a worthwhile endeavor since:
1. All cancers are detectable in one manner or another
2. The earlier a cancer is detected, the higher the chance of survival
3. Late-stage cancer treatment is incredibly expensive
What's the closest, and least expensive, procedure(s) someone can have annually (or every two years) that would give them a relative leg up on any potential cancers?
Premise 2 is inaccurate for some cancers.
Premise 1 is inaccurate inasmuch as there are some cancers that would not be detectable on any imaginable kind of routine screening; for example, my mother-in-law died of a non-site-specific cancer that was probably related to her earlier experiences of endometriosis. She was not diagnosed until the complications of abdominal fluid retention prompted the docs to run cytology on the fluid, which detected markers similar to ovarian cancer, though her ovaries themselves were clear of any cancerous masses.
That said, there are lots of routine screenings recommended for commonly experienced cancers: here are the American Cancer Society's guidelines.
posted by Sidhedevil at 3:06 PM on November 10, 2010 [1 favorite]
Premise 1 is inaccurate inasmuch as there are some cancers that would not be detectable on any imaginable kind of routine screening; for example, my mother-in-law died of a non-site-specific cancer that was probably related to her earlier experiences of endometriosis. She was not diagnosed until the complications of abdominal fluid retention prompted the docs to run cytology on the fluid, which detected markers similar to ovarian cancer, though her ovaries themselves were clear of any cancerous masses.
That said, there are lots of routine screenings recommended for commonly experienced cancers: here are the American Cancer Society's guidelines.
posted by Sidhedevil at 3:06 PM on November 10, 2010 [1 favorite]
Cancer isn't one single disease or condition. Some are caused by exposure to certain things; others appear in people whose genetics make them more susceptible; still others appear for what might seem like no reason at all. Treatment can be the same way: one type can be excised completely, while another will recur no matter what you do.
I HATE it when people say they want to find a cure for cancer. You might as well say that you want to fix "stuff."
posted by Madamina at 3:11 PM on November 10, 2010 [9 favorites]
I HATE it when people say they want to find a cure for cancer. You might as well say that you want to fix "stuff."
posted by Madamina at 3:11 PM on November 10, 2010 [9 favorites]
What's the closest, and least expensive, procedure(s) someone can have annually (or every two years) that would give them a relative leg up on any potential cancers?
As others have pointed out, there's no one catch-all gold standard test for cancer. You'd have to combine a bunch: a full MRI, a CT, a colonoscopy, an upper endoscopy, various blood tests, genetic screening, and whatever sex-appropriate tests (e.g. mammogram, prostate exam). Just for starters, the MRI and CT won't be cheap, especially if your insurance won't pay for them (and it probably won't). Think several thousand dollars.
Another problem is that only some of these actually make financial sense when you're talking about the population as a whole. Annual MRIs for everybody would cost a fortune and wouldn't catch enough cancers to be worth it. Annual CTs and other X-ray-based tests for everybody would probably cause more cancers than they would catch.
Another problem is the false positive rate and what might be called the 'overreaction rate.' Do this kind of screening across the board and you'd get a lot of unnecessary biopsies and surgeries on benign tumors. Compare to the prostate screening problem: we screen a bunch of people, many of whom do have prostate cancer, but many of those cancers are either benign or grow so slowly that something else will kill the patient first, to put it bluntly. In the meanwhile a bunch of unnecessary surgeries are done with a lot of side effects: anesthesia and infection-related death, incontinence, impotence, etc.
Anyway, if you really want to go down that road, look into 'full body scans' and the like. But be warned: many clinics offering such scans are relying on people's fear of cancer and lack of understanding of the statistics involved. They are very much in it for the money.
posted by jedicus at 3:15 PM on November 10, 2010
As others have pointed out, there's no one catch-all gold standard test for cancer. You'd have to combine a bunch: a full MRI, a CT, a colonoscopy, an upper endoscopy, various blood tests, genetic screening, and whatever sex-appropriate tests (e.g. mammogram, prostate exam). Just for starters, the MRI and CT won't be cheap, especially if your insurance won't pay for them (and it probably won't). Think several thousand dollars.
Another problem is that only some of these actually make financial sense when you're talking about the population as a whole. Annual MRIs for everybody would cost a fortune and wouldn't catch enough cancers to be worth it. Annual CTs and other X-ray-based tests for everybody would probably cause more cancers than they would catch.
Another problem is the false positive rate and what might be called the 'overreaction rate.' Do this kind of screening across the board and you'd get a lot of unnecessary biopsies and surgeries on benign tumors. Compare to the prostate screening problem: we screen a bunch of people, many of whom do have prostate cancer, but many of those cancers are either benign or grow so slowly that something else will kill the patient first, to put it bluntly. In the meanwhile a bunch of unnecessary surgeries are done with a lot of side effects: anesthesia and infection-related death, incontinence, impotence, etc.
Anyway, if you really want to go down that road, look into 'full body scans' and the like. But be warned: many clinics offering such scans are relying on people's fear of cancer and lack of understanding of the statistics involved. They are very much in it for the money.
posted by jedicus at 3:15 PM on November 10, 2010
What's the closest, and least expensive, procedure(s) someone can have annually (or every two years) that would give them a relative leg up on any potential cancers?
This doesn't exist. As it is, well established cancer screening tests like mammography pick up false positives and don't have 100 percent sensitivity.
Many tests carry inherent risks. With colonoscopy 1 in 10,000 colonoscopies results in death. In Ontario, where I live, 172102 colonoscopies were performed in 2001/02 for example. So, 17 people probably died.
If you have your body screened annually or every two years, and expect to have anything suspicious-looking cut out you also may needlessly be subjecting yourself to surgery, which carries its own risk of death and will get expensive when you're treating a population of otherwise healthy people.
posted by waterandrock at 3:29 PM on November 10, 2010
This doesn't exist. As it is, well established cancer screening tests like mammography pick up false positives and don't have 100 percent sensitivity.
Many tests carry inherent risks. With colonoscopy 1 in 10,000 colonoscopies results in death. In Ontario, where I live, 172102 colonoscopies were performed in 2001/02 for example. So, 17 people probably died.
If you have your body screened annually or every two years, and expect to have anything suspicious-looking cut out you also may needlessly be subjecting yourself to surgery, which carries its own risk of death and will get expensive when you're treating a population of otherwise healthy people.
posted by waterandrock at 3:29 PM on November 10, 2010
From a pure technical perspective, 'cancer' refers to a variety of diseases, most of which share one marker. Cells multiply at an out of control rate, but some cancers will metastasize and others won't, some release certain hormones and others won't... the only things that cancers seem to have in common are those defined in to the term. And so measuring this-and-such chemical which is associated with, say, prostate cancer, isn't going to tell you anything about that-and-so chemical associated with ovarian cancer, or about the chemical signals associated with leukemia, or...
More practically, the base assumption that "all cancers are worth detecting" isn't correct either. They're not all dangerous/going to kill you. In addition to false positives there's a risk to cancer treatment, and there's good reason to only undergo it when your life is at risk. However, our statistics/heuristics on this aren't very good: people who seek treatment and screening due to feeling ill, or who die of cancer, all get included in the statistics and our mental sense of what 'cancer' is, whereas all the people who never notice that funny mole and eventually die of old age don't. One good counterexample is that a study was done showing that half of all men have prostate cancer at time of death (and it wasn't what killed them). What would be the costs to those men of being diagnosed and treated as 'cancer patients'? (Of course, this study is usually interpreted as "half of all men have CANCER OMG we should diagnose them better!" like it's "cancer" that's inherently the problem rather than "stuff that will kill you".)
The danger posed by false positives also only goes up the rarer the disease is - if one person in 10,000 has the disease, then screening a million people with a 1% false pos/false neg rate gives you 99 positive results that actually have it, 1 negative result that has it, and 9999 positive results that don't. 1% false positive rate is pretty good for cancer screenings, as far as I can tell from a quick googling. We work around this by only scanning people who show some other symptom or evidence for having the disease, or only people who fall into a high-risk group such that more than 1/10,000 will have .
posted by Lady Li at 3:53 PM on November 10, 2010 [2 favorites]
More practically, the base assumption that "all cancers are worth detecting" isn't correct either. They're not all dangerous/going to kill you. In addition to false positives there's a risk to cancer treatment, and there's good reason to only undergo it when your life is at risk. However, our statistics/heuristics on this aren't very good: people who seek treatment and screening due to feeling ill, or who die of cancer, all get included in the statistics and our mental sense of what 'cancer' is, whereas all the people who never notice that funny mole and eventually die of old age don't. One good counterexample is that a study was done showing that half of all men have prostate cancer at time of death (and it wasn't what killed them). What would be the costs to those men of being diagnosed and treated as 'cancer patients'? (Of course, this study is usually interpreted as "half of all men have CANCER OMG we should diagnose them better!" like it's "cancer" that's inherently the problem rather than "stuff that will kill you".)
The danger posed by false positives also only goes up the rarer the disease is - if one person in 10,000 has the disease, then screening a million people with a 1% false pos/false neg rate gives you 99 positive results that actually have it, 1 negative result that has it, and 9999 positive results that don't. 1% false positive rate is pretty good for cancer screenings, as far as I can tell from a quick googling. We work around this by only scanning people who show some other symptom or evidence for having the disease, or only people who fall into a high-risk group such that more than 1/10,000 will have .
posted by Lady Li at 3:53 PM on November 10, 2010 [2 favorites]
There is an ovarian cancer study going on in the McGill hospitals, working toward finding better ways of detecting that specific cancer. One of the things they check for is a specific tumor marker in the blood. I don't know whether all cancers have such markers, but it would seem to me to be a potentially useful kind of test: have your blood drawn once yearly and run a test for known markers. But I don't know how close that is. I don't think you can do it now.
posted by zadcat at 4:06 PM on November 10, 2010
posted by zadcat at 4:06 PM on November 10, 2010
Anyway, if you really want to go down that road, look into 'full body scans' and the like. But be warned: many clinics offering such scans are relying on people's fear of cancer and lack of understanding of the statistics involved. They are very much in it for the money.
In addition to these excellent concerns, note also that these tests do not offer much comfort for gastrointestinal cancers because they require the use of contrasting agents and/or invasive scopes to get a reliable result.
posted by gabrielsamoza at 4:24 PM on November 10, 2010
In addition to these excellent concerns, note also that these tests do not offer much comfort for gastrointestinal cancers because they require the use of contrasting agents and/or invasive scopes to get a reliable result.
posted by gabrielsamoza at 4:24 PM on November 10, 2010
The earlier a cancer is detected, the higher the chance of survival
Orac is a blogger who is a surgeon and breast cancer researcher. He has written extensively (1, 2, 3, 4, 5, 6, 7, 8, 9) on the topic of mammography and the overdiagnosis of breast cancer. He makes a compelling case for why earlier is not better, and why it makes sense to recommend that asymptomatic women under 50 should not have routine mammograms, and only biennial mammograms for women between 50 and 74 (the current USPSTF screening recommendations.)
posted by Rhomboid at 4:54 PM on November 10, 2010 [5 favorites]
Orac is a blogger who is a surgeon and breast cancer researcher. He has written extensively (1, 2, 3, 4, 5, 6, 7, 8, 9) on the topic of mammography and the overdiagnosis of breast cancer. He makes a compelling case for why earlier is not better, and why it makes sense to recommend that asymptomatic women under 50 should not have routine mammograms, and only biennial mammograms for women between 50 and 74 (the current USPSTF screening recommendations.)
posted by Rhomboid at 4:54 PM on November 10, 2010 [5 favorites]
What's the closest, and least expensive, procedure(s) someone can have annually (or every two years) that would give them a relative leg up on any potential cancers?
Eat a variety of food, maintain a healthy weight, don't smoke, get some exercise, wear sunscreen, and get regular general physicals.
I'm not being glib. This really is the way to get a relative leg up on any potential cancers.
posted by desuetude at 6:49 PM on November 10, 2010 [3 favorites]
Eat a variety of food, maintain a healthy weight, don't smoke, get some exercise, wear sunscreen, and get regular general physicals.
I'm not being glib. This really is the way to get a relative leg up on any potential cancers.
posted by desuetude at 6:49 PM on November 10, 2010 [3 favorites]
There's not one. For any type of cancer screening, insurance generally won't cover it unless it was part of a recommended screening guideline for your age, sex, etc., or you are symptomatic. However, even if money was no object, there's just not one single test that is used to catch cancers early. A lot of the available body scans would only catch cancers that were further progressed than they would be caught by other screenings. The tumor marker tests are, for the most part, not reliable enough to use for mass screenings. They're typically only used in people with a family history, or who have symptoms. Cancer is not one disease, it's a term for a category of illnesses, basically. There will almost certainly never be one test for all cancer or one cure for all cancer.
posted by elpea at 11:33 PM on November 10, 2010
posted by elpea at 11:33 PM on November 10, 2010
Would anyone have a colonoscopy if there was a generic way to test for colon cancer like a blood test?
posted by smackfu at 6:47 AM on November 11, 2010
posted by smackfu at 6:47 AM on November 11, 2010
This thread is closed to new comments.
posted by pullayup at 3:04 PM on November 10, 2010