Re-evaluating the Benefits of Cancer Screening
uncleO writes "An article in the NY Times describes two studies that weigh the harm caused by cancer screenings against the benefits they provide. From the article, 'Two recent clinical trials of prostate cancer screening cast doubt on whether many lives — or any — are saved. And it said that screening often leads to what can be disabling treatments for men whose cancer otherwise would never have harmed them. A new analysis of mammography concluded that while mammograms find cancer in 138,000 women each year, as many as 120,000 to 134,000 of those women either have cancers that are already lethal or have cancers that grow so slowly they do not need to be treated. ... In recent years, researchers have found that many, if not most, cancers are indolent. They grow very slowly or stop growing altogether. Some even regress and do not need to be treated — they are harmless."
Justin Bieber has stopped growing, but that doesn't make him harmless.
When the foot seeks the place of the head, the line is crossed. Know your place. Keep your place. Be a shoe.
...please follow suit and just go away?
Thanks,
Humanity
They rob pharmaceutical companies of revenue streams that are rightfully theirs.
I was told years ago that the average person has between 3 - 5 'cancers' in their body at any given time.
They are usually destroyed by your immune system and you never know it. ( the size being one interesting component).
I guess the question is how do you tell the ones that need treatment from the ones that don't before it it too late to treat the ones that do. Also, treatment itself is really dangerous. Chemo therapy had a 50% survival read for a perfectly healthy person, last time I checked. When it comes to this, we are no where near having all the answers.
And the UK is now reviewing the entire breast screening programme it runs to see whether the evidence continues to show that, on balance, good outweighs harm. Tough decisions for all concerned, and an excellent demonstration of just why science is hard to do right.
Among the options:
1) Continue as-is
2) Use more selective screening with (hopefully) greater specificity -- eg familial history, gene markers, etc
3) Stop screening
I'm curious why blood tests aren't peformed regularly. You can certainly request Alpha-fetoprotein (AFP) any time you like, but it is not commonly recommended on a regular basis. AFP can indicate tumors growing in the body. Very high levels of AFP can indicate advanced cancer. In the case of a co-worker who was found to have advanced cancer, on first diagnosis, why not have this marker checked every 6 months?
I've been told a normal reading is about 100-120. Values over 10,000 should be investigated. Lance Armstrong, had levels of over 100,000 when he was diagnosed, with tumors spread throughout his body.
It seems a low impact test, why is it not advised as part of a standard checkup? We'll look for chelesterol, why not Alpha-fetoprotein?
A feeling of having made the same mistake before: Deja Foobar
Deaths caused by cancer (US numbers, 2009): 562,875
Deaths caused by heart disease (US, 2009): 616,067
We know more about Heart Disease, but it gets less press - mainly because the treatments for it are not as painful.
You know, I bet if someone created a painful, dramatic, balding cure for Heart Disease that in 10 years we would cure it entirely.
excitingthingstodo.blogspot.com
The problem is they have difficulty, with prostate cancer, in telling which are slow growing and which are aggressive.
Seems like someone is driving a huge PR campaign for "let's not have people visit doctors and get cancer screening". It's likely actually just costing a group of HMO insurers more money to have lots of people treat cancers early and undergo lengthy treatment, and then survive, rather than have a smaller number of people detect it too late, do a short treatment, and then just die.
After all, health services are a business. We understand. You can't just have insured people liviing a long time and making businesses lose money.
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In other words, since we are about to have huge waiting lists for routine tests, lets just declare that is a feature instead of a bug.
Just more of the stuff we find out after passing Obamacare I guess. And notice how I will be flamed for calling it that, which says it all. If this turd were actually popular I'd be called a racist if I DIDN'T give President Obama proper credit for his signature achievement.
Democrat delenda est
It does not mean that screening is useless; it means the medical community doesn't know nearly as much about cancers as they have been trying to convince us. (and maybe they need a big dose of humility)
What this info really means is that we need better tools to distinguish which patients will benefit from treatment, and which will not. In this case, closing our eyes does not make the Ravenous Bugblatter Beast of Traal unaware of our presence.
"have cancers that are already lethal"
--> People that have lethal cancer can be treated nevertheless.
--> how do you know if a persons cancer will be lethal or not?
"cancers that grow so slowly they do not need to be treated"
--> how can you tell if a cancer will grow and kill or not?
What i read here is that you save 4.000 to 18.000 people anyways,
and for all the others you open up the evaluation of their disease.
So ... what kind of idiot wrote that pretentious article
Another approach is to find an imaging technique that is cheap and harmless enough that you could image someone's whole body every week. Then you could compare week to week to monitor growth and spread of the tumors, and only target tumors that are fast growing, or persist beyond a certain threshold size.
I've seen these and similar studies crop up recently. They really bother me because while they are technically right, I don't think their conclusions are helpful. One problem they point out is that once you've been diagnosed, so many times it is "too late". Their conclusion? Screening test are not as important as we thought. WRONG. If anything this points to MORE FREQUENT screening of assorted cancers. It's easy to be so dismissive of cancer when you are thinking about these things statistically...it's entirely different if you know anyone who has had cancer or if you yourself get it. I am starting to get "older" and am approaching an age where I personally believe I should start getting screened. When I start, I plan on doing this very often. To me, it is worth having a finger up my ass and some amount of money not to die a slow, painful death from something I could have caught and treated. If you want to take the gamble and bet with the statistics, then by all means do. I, however, plan on living as long and healthy as possible.
as many as 120,000 to 134,000 of those women either have cancers that are already lethal or
There are a lot of cancers that are incurable, but can still be controlled for a while. Statements like this make it sound as though catching these cancers early and controlling them for a while is a worthless endeavor.
My wife is one year into a battle with a cancer that she has only roughly a 25% chance of surviving with treatment. Without treatment, she would have been dead a few weeks after diagnosis. She is grateful to have spent the past year alive instead of dead, and of course the children and I are also grateful. I guess the point that I'm trying to make here is that treating a cancer that will most likely be lethal still has significant value. None of us would have been very happy if some government bureaucrat had told us that since the cancer was so likely to kill her, they wouldn't bother treating.
They don't grade fathers, but if your daughter's a stripper, you fucked up. --Chris Rock
Some diagnostic tests (breast cancer screening, for example) increase the risk of contracting the disease you are screening for.
In the case of the prostate cancer study, it seems that treatment of detected, but actually benign, tumors was causing more mortality than just living in ignorance of them.
My dad got radiation for prostate cancer and the treatment seems to have been effective at mostly eliminating the cancer. His PSA score is way down now too. But, he now wears Depends because the radiation made him incontinent. He's 74. I suspect his case is typical. If they had done nothing to treat the cancer, he may well have been better off.
People read these articles and too many come away with "we shouldn't be screening for cancer". That's not what it's saying at all. It's saying "we shouldn't rely on our current screening tests". That's the key. Screening isn't a problem. Early detection isn't a problem. Inaccurate screening tests that encourage treatment when none would be necessary is the problem. That's what the US Preventive Services Task Force is trying to say: shitty tests create shitty outcomes.
It's like trying to use just a thermometer to diagnose H1N1 or Ebola. Well, you'd also catch the standard flu, or a head cold, or appendicitis, or a thousand other things that cause a fever. The prostrate screening test just tests for the known prostrate cancer antigen... but it's not very specific to the type of cancer present. That's the problem. Doctors and patients are stuck in the mindset of If (Cancer == True) { CancerTreatment(); }. That said, cancer treatment involves really dangerous and destructive things to the human body. Many cancer patients die from treatment as much as from the disease. They're akin to poisoning the whole body and hoping that you kill the cancerous bits before you kill the patient. This means that that Cancer == True test better damn well be pretty reliable and accurate. It's a reminder of the basis of medical ethics: primum non nocere -- first, do no harm. The data says doctors are doing a lot of harm if 120,000 of 138,000 cases (87%) have unwarranted treatments.
So, again, they're not saying "don't screen". They're saying "don't screen with shitty tests; get better tests, then screen."
The road to tyranny has always been paved with claims of necessity.
Whether the cancer was going to end up harmless or end up killing a person, it's better that they at least know if its existence and have the choice of whether or not they want treatment.
I was tested for prostate cancer recently as part of a series of tests to check my previous cancer hadn't come back, and my doctor explained the chance of a false result, and the pros and cons of surgery if anything as found. A lot of information to read and I had to give my consent before they'd do the test.
The change in policy stems from good mathematics, namely good statistics. Where the number of people who are subjected to a test may suffer from one of two failures,
a) false negative - that is the test fails to detect the presence of a disease and thus incorrectly reports a negative results, and
b) false positive, the test incorrectly reports a positive result, but the disease is not actually present.
The problem is that with a large pool of test population and a small affected sub-population, the misleading results are counter-intuitive, and can end up causing more harm (otherwise healthy individuals undergoing unnecessary biopsies, radiation, and chemotherapy increase mortality rate) to the overall population.
See The dangers of false positives by Dr. Dave Richeson, don't take my word on it.
Let's see if I have this right:
When people receive bad news about their health, they often make poor decisions about treatment.
Solution: Stop screening and therefore, there won't be any bad news to report.
What? Unless the testing itself is a hazard, we shouldn't be cutting off a potentially life saving source of information. We should be working on improving the decision making process. If most prostate cancers should not be treated then recognize this and develop an alternative response. Perhaps more extensive tests for those who come up positive. Perhaps more frequent tests. Maybe just wait and see if it has grown by the time next years test rolls around.
The general arguement is that 'screening comes with harms as well as benefits' (from TFA), which is false unless you believe that listening to the heart leads to side effects from open-heart surgery because too many false positive heart diseases or indolent heart conditions are overly treated. The problem lies within understanding the results and the possible outcomes from different treatments. For example, if cancer is found that is possibly slow growing or indolent, then go into a "watchful monitoring" treatment of more frequent and different checks. Because we have great screening systems that will be able to detect disease earlier and earlier, we need to understand that there is a point at which a disease is so early it is not worth treating. But it does not mean we should not look.
In othehr words, because bad actions can be taken as a result of getting the correct diagnosis information, then we need to fix our analysis and recommendation for treatments. Lets not stick our heads in the sand and not even look for the disease.
Isn't this another instance of the 'Fallacy of the Commons'? Maybe it's true that the cost of full community screening is not matched by the net benefit of all outcomes. But for me, I sure want to pay the cost of anything that might give me more life or comfort. It's clearer if you don't expect 'the community' to pay (or the insurer who mutualises community risks). How does your own money vote? And would that optimise community benefit?
here are already bureaucrats sitting between you and your doctor--the private insurance companies--and you already have limited mobility between providers
So the answer is to REDUCE mobility even further by having essentially just one provider? 99% of us have no preexisting conditions that would prevent us from moving, but plenty of regulations in the way like the ones barring me from purchasing insurance across state lines.
I have never understood the course of philosophy that thinks you can make something better by distilling the essence of what is wrong and making it 1000x more potent a concern.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
Been there. Repeated medium-high PSA test results. Got a biopsy. Not painful, no harm done. If the samples show nothing, you stop here. Or you have some "core samples" that show some cancer cells in which case you get something called a Gleason score which is a measure of the cancer's aggressiveness. The combination of how many of the samples are cancer and how aggressive the cancer is determines if you should do something about it....together with your age and overall health.
There are several treatments and surgery is only one. In my case I chose radiation and had radioactive seeds implanted followed by beam radiation for 35 sessions. My doctor was able to give me a probability of cure before we started the treatments using the same criteria that the best surgical team uses.
3 years later I have tested cancer free and have no symptoms that bother me from the treatment. Expensive, yes. 20 years ago they couldn't detect the cancer and by the time they saw the patient, the cancer had spread to other parts of the body...a horrible way to die. Now they can treat the problem. Do research and choose the best doctors as the experience of the doctors is as important as which treatment you choose. Go to someone who keeps statistics on how they treat their patients and what the results are. In my case, I am tested every 6 months for life and contribute those results to the team's data base.
Glad I had the tests.
If you have a family history of prostate cancer or if you are black (which increases the probability), start getting tested at age 40.
My colonoscopy at 53 (3 years late) detected the start of malignant cancer. My gastro guy described my situation as "having *just* missed being hit by the bus. Without treatment, I'd have been dead in less than 5 years, give or take a year.
So, better safe than sorry has become my new motto. The social and economic cost, in the scheme of things, is trivial (That is, if you have health insurance. If you don't, unofficial government policy is the usual de facto homicide applied to the poor).
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without the test you never have the choice between treating and not treating. This sounds like a study conducted by wealthy @$$es to discourage middle class people from seeking medical treatment. I don't see Senators turning down treatment. What was that qoute? "In America, If you get sick better die quick!".
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The efficacy of a medical test is determined by three numbers.
1) The real incidence rate - what percent of the population (after the fact) actually has the condition.
2) The false positive rate.
3) The false negative rate.
The problem with the PSA test is that while the real incidence rate is relatively high, the false positive and false negative rates are extremely high.
1) The incidence rate varies with age and ethnicity. According to the CDC (and wikipedia, for what it's worth), (http://www.cdc.gov/cancer/prostate/statistics/race.htm), the age-averaged rate is 100 per 100,000 for asians, 160 per 100,000 for white and 250 per 100,000 for black men. But they don't recommend the test for men under 45. And age really is the determining factor. (http://seer.cancer.gov/publications/prostate/inc_mort.pdf). So, let's assume an incidence rate of 10% for 55 year old men for purposes of this exercise. - for 75 year old men, it's probably closer to 90%, for 20 year old men, essentially zero.
2) According to the National Cancer Institute (http://www.cancer.gov/cancertopics/factsheet/detection/PSA), the false positive rate is 65-75%. Giving the test the best chance, I'll take the lower limit of 65%.
3) I haven't found a definitive source for the false negative rate, but wikipedia cites a paper giving a 25% false negative rate. Let's give it the benefit of the doubt and call it 20%.
Source...
^ Thompson IM, Pauler DK, Goodman PJ, Tangen CM, Lucia MS, Parnes HL, Minasian LM, Ford LG, Lippman SM, Crawford ED, Crowley JJ, Coltman CA (May 2004). "Prevalence of prostate cancer among men with a prostate-specific antigen level or 4.0 ng per milliliter". N. Engl. J. Med. 350 (22): 2239–46)
So - give a population of 1 million men a PSA test and here's what you get.
100,000 men have prostate cancer
900,000 do not have prostate cancer.
Of the 100,000 men who DO have prostate cancer...
a) 20,000 test negative (a problem, but what are you going to do? This was my father's case (see below))
b) 80,000 test positive (okay, but do you need treatment? Odds are you'll die of something else first (see below))
Of the 900,000 who do NOT have prostate cancer.
c) 585,000 test positive (the real problem)
d) 315000 test negative. (good on yer.)
The real problem is that honking huge false positive rate. If you test positive, there's still less than a 50% chance that you actually have prostate cancer, and even if you do, it's probably not going to make a damn bit of difference over the course of your life, but it's still very very scary and you get a biopsy or have radiation treatment and risk impotence and/or incontinence and possibly seriously reduce your quantity of life for the rest of your life for no good reason. It's even more complicated by the fact that the PSA level goes up naturally as you age. If your level goes from 4 to 10 over 10 years, what does it mean? Flip a coin.
That said, given that my father, both his brothers and my paternal grandfather all died from prostate cancer (between the ages of 90 and 94, I'll grant you - that's the thing. The vast majority of men will die of something else before the prostate cancer kills them), my doctor recommends continuing to take the test every 5 years.
This is nothing but trying to whip up 'consensus' that testing is not needed. This will save the single payer hellcare system big bucks.
My partner has Leukemia, her oncologist told her that he expected her to have two weeks left - that was 9 years ago. The radiation accumulated from the treatments has caused at least as many health issues as the luke itself.
While her tests aren't stable or good enough for them to say she is in remission the most treatment she can have these days is heavy doses of strong antibiotics when she goes downhill.
The best way to beat a life threatening disease is to believe you can win. It may be cliched an all but you can either lay down and let it beat you or stand tall and win the fight.
in the U.S. and the U.K. it is still illegal to claim that cancer can be cured. i find it ridiculous that it has to be called "regression"... ah well...
Doesn't matter what actual studies find. ABC News will film someone who'll definitively state "The only reason I'm alive today is because the prostate/breast/colorectal/whatever screening caught my cancer. I just can't understand those doctors wanting to stop the test that saved my life!" Intercut the scientifically illiterate telegenic reporter nodding sympathetically. Then go back to Diane Sawyer in the studio giving the network's medical expert 37 seconds to explain how on earth *NOT* finding cancers is a good idea. And he'll just say "Uh, it's complicated... go talk to your doctor."
This stuff is just too hard for people, they don't have the math skills for it. But that doesn't prevent them from "knowing" what's right.
=S
So what's the solution? I think its to research more so you can come up with a reliable, cheap way to differentiate between all the 4 below. preferably with minimal side effects "1. You find a cancer that will eventually kill you AND that particular cancer has a treatment that works better when started earlier. (True Positive result) 2. You don't find a cancer that you don't have. (True Negative result) 3. You find a cancer or something that looks like a cancer however it will grow so slowly or regress so it won't cause any harm, but then you don't really know which is which so you elect to be treated for same with some morbidity or mortality. (False Positive result) 4. You don't find the cancer that existed and goes off to knock you off just before you design the next iPad killer. (False negative result)." properly Identifying which tumors are slow growing and which patients are too late would solve a lot of problems. of course this is easier said than done
Death panels. Liberal jobby chasers
The new right fascists are bilingual. They speak English and Bullshit.
Whether it is the defense industry, the corrections industry or the healthcare industry big money and the promise of lucre cause the industry to bloat well past any benefit to society. Basic to this process is the incessant selling of FUD: "You're going to be enslaved by communists." "You're going to be victimized by criminals." "You're going to die of cancer". And so on ...