Can governments afford to give up their addiction to cigarette taxes? That is the issue this New York Times article raises.
Duncan
....the government has become a financial stakeholder in smoking, some would argue, even as public health officials warn people about its deadly consequences. Smoking declines as cigarette taxes increase, but a core group of smokers hang on to the habit.
The reliance of government coffers on the taxes smokers pay, and on the tobacco settlement money, essentially provides a financial cushion for state governments and could be viewed as a government guarantee for the survival of the tobacco industry. Would politicians shut down an industry that supplies so much money?
http://snipurl.com/3r6e2
Wednesday, September 17, 2008
Sunday, September 14, 2008
Mammography Dangers To Be Aware Of
While mammograpy has its' uses and benefits, it is not completely benign especially for younger women. Samuel Epstein, author of Politics of Cancer, who has been analyzing cancer for decades, provides information all women should be aware of.
Duncan
Dangers and Unreliability of Mammography: Part 1
by Samuel Epstein, MD
Contrary to popular belief and misleadingly assurances by the media, the National Cancer Institute (NCI), and American Cancer Society (ACS), mammography is not a technique for early diagnosis. In fact, a breast cancer has usually been present for about eight years before it is usually detected.
Mammography poses major risks of which women still remain uninformed. Radiation from routine mammography poses cumulative risks of breast cancer. Contrary to misleading assurances that radiation exposure from mammography is trivial and similar to that from a chest X ray, about 1/1,000 of a rad (radiation-absorbed dose), the routine practice of taking four films for each breast results in some 1,000-fold greater exposure, 1 rad, focused on each breast rather than the entire chest. Thus, premenopausal women screened annually over ten years are exposed to about 10 rads for each breast.
The premenopausal breast is also highly sensitive to radiation with each rad exposure increasing breast cancer risk by 1 percent, resulting in a cumulative 10 percent increased risk over ten years of screening; risks are still greater for "baseline" screening at younger ages, for which there is no evidence of future relevance. Furthermore, cancer risks are up to fourfold greater for the 2 percent of women who are unknowing carriers of the A-T gene, and thus highly sensitive to radiation; estimatedly, this accounts for 20 percent of breast cancers annually.
Click link for more:
http://www.newliving.com/issues/apr_2005/articles/mammography.html
Here is a link to a much more complete though more difficult essay by Epstein on mammography dangers:
http://www.preventcancer.com/patients/mammography/ijhs_mammography.htm
Duncan
Dangers and Unreliability of Mammography: Part 1
by Samuel Epstein, MD
Contrary to popular belief and misleadingly assurances by the media, the National Cancer Institute (NCI), and American Cancer Society (ACS), mammography is not a technique for early diagnosis. In fact, a breast cancer has usually been present for about eight years before it is usually detected.
Mammography poses major risks of which women still remain uninformed. Radiation from routine mammography poses cumulative risks of breast cancer. Contrary to misleading assurances that radiation exposure from mammography is trivial and similar to that from a chest X ray, about 1/1,000 of a rad (radiation-absorbed dose), the routine practice of taking four films for each breast results in some 1,000-fold greater exposure, 1 rad, focused on each breast rather than the entire chest. Thus, premenopausal women screened annually over ten years are exposed to about 10 rads for each breast.
The premenopausal breast is also highly sensitive to radiation with each rad exposure increasing breast cancer risk by 1 percent, resulting in a cumulative 10 percent increased risk over ten years of screening; risks are still greater for "baseline" screening at younger ages, for which there is no evidence of future relevance. Furthermore, cancer risks are up to fourfold greater for the 2 percent of women who are unknowing carriers of the A-T gene, and thus highly sensitive to radiation; estimatedly, this accounts for 20 percent of breast cancers annually.
Click link for more:
http://www.newliving.com/issues/apr_2005/articles/mammography.html
Here is a link to a much more complete though more difficult essay by Epstein on mammography dangers:
http://www.preventcancer.com/patients/mammography/ijhs_mammography.htm
Saturday, September 13, 2008
Wonderful Essay on (Cancer) Statistics
I highly recommend this essay by Stephen Gould for anyone dealing with cancer, or supporting someone with cancer..
Duncan
The Median Isn't the Message by Stephen Jay Gould
My life has recently intersected, in a most personal way, two of Mark Twain's famous quips. One I shall defer to the end of this essay. The other (sometimes attributed to Disraeli), identifies three species of mendacity, each worse than the one before - lies, damned lies, and statistics.
Consider the standard example of stretching the truth with numbers - a case quite relevant to my story. Statistics recognizes different measures of an "average," or central tendency. The mean is our usual concept of an overall average - add up the items and divide them by the number of sharers (100 candy bars collected for five kids next Halloween will yield 20 for each in a just world). The median, a different measure of central tendency, is the half-way point. If I line up five kids by height, the median child is shorter than two and taller than the other two (who might have trouble getting their mean share of the candy). A politician in power might say with pride, "The mean income of our citizens is $15,000 per year." The leader of the opposition might retort, "But half our citizens make less than $10,000 per year." Both are right, but neither cites a statistic with impassive objectivity. The first invokes a mean, the second a median. (Means are higher than medians in such cases because one millionaire may outweigh hundreds of poor people in setting a mean; but he can balance only one mendicant in calculating a median).
The larger issue that creates a common distrust or contempt for statistics is more troubling. Many people make an unfortunate and invalid separation between heart and mind, or feeling and intellect. In some contemporary traditions, abetted by attitudes stereotypically centered on Southern California, feelings are exalted as more "real" and the only proper basis for action - if it feels good, do it - while intellect gets short shrift as a hang-up of outmoded elitism. Statistics, in this absurd dichotomy, often become the symbol of the enemy. As Hilaire Belloc wrote, "Statistics are the triumph of the quantitative method, and the quantitative method is the victory of sterility and death."
This is a personal story of statistics, properly interpreted, as profoundly nurturant and life-giving. It declares holy war on the downgrading of intellect by telling a small story about the utility of dry, academic knowledge about science. Heart and head are focal points of one body, one personality.
In July 1982, I learned that I was suffering from abdominal mesothelioma, a rare and serious cancer usually associated with exposure to asbestos. When I revived after surgery, I asked my first question of my doctor and chemotherapist: "What is the best technical literature about mesothelioma?" She replied, with a touch of diplomacy (the only departure she has ever made from direct frankness), that the medical literature contained nothing really worth reading.
Of course, trying to keep an intellectual away from literature works about as well as recommending chastity to Homo sapiens, the sexiest primate of all. As soon as I could walk, I made a beeline for Harvard's Countway medical library and punched mesothelioma into the computer's bibliographic search program. An hour later, surrounded by the latest literature on abdominal mesothelioma, I realized with a gulp why my doctor had offered that humane advice. The literature couldn't have been more brutally clear: mesothelioma is incurable, with a median mortality of only eight months after discovery. I sat stunned for about fifteen minutes, then smiled and said to myself: so that's why they didn't give me anything to read. Then my mind started to work again, thank goodness.
If a little learning could ever be a dangerous thing, I had encountered a classic example. Attitude clearly matters in fighting cancer. We don't know why (from my old-style materialistic perspective, I suspect that mental states feed back upon the immune system). But match people with the same cancer for age, class, health, socioeconomic status, and, in general, those with positive attitudes, with a strong will and purpose for living, with commitment to struggle, with an active response to aiding their own treatment and not just a passive acceptance of anything doctors say, tend to live longer. A few months later I asked Sir Peter Medawar, my personal scientific guru and a Nobelist in immunology, what the best prescription for success against cancer might be. "A sanguine personality," he replied. Fortunately (since one can't reconstruct oneself at short notice and for a definite purpose), I am, if anything, even-tempered and confident in just this manner.
Hence the dilemma for humane doctors: since attitude matters so critically, should such a sombre conclusion be advertised, especially since few people have sufficient understanding of statistics to evaluate what the statements really mean? From years of experience with the small-scale evolution of Bahamian land snails treated quantitatively, I have developed this technical knowledge - and I am convinced that it played a major role in saving my life. Knowledge is indeed power, in Bacon's proverb.
The problem may be briefly stated: What does "median mortality of eight months" signify in our vernacular? I suspect that most people, without training in statistics, would read such a statement as "I will probably be dead in eight months" - the very conclusion that must be avoided, since it isn't so, and since attitude matters so much.
I was not, of course, overjoyed, but I didn't read the statement in this vernacular way either. My technical training enjoined a different perspective on "eight months median mortality." The point is a subtle one, but profound - for it embodies the distinctive way of thinking in my own field of evolutionary biology and natural history.
We still carry the historical baggage of a Platonic heritage that seeks sharp essences and definite boundaries. (Thus we hope to find an unambiguous "beginning of life" or "definition of death," although nature often comes to us as irreducible continua.) This Platonic heritage, with its emphasis in clear distinctions and separated immutable entities, leads us to view statistical measures of central tendency wrongly, indeed opposite to the appropriate interpretation in our actual world of variation, shadings, and continua. In short, we view means and medians as the hard "realities," and the variation that permits their calculation as a set of transient and imperfect measurements of this hidden essence. If the median is the reality and variation around the median just a device for its calculation, the "I will probably be dead in eight months" may pass as a reasonable interpretation.
But all evolutionary biologists know that variation itself is nature's only irreducible essence. Variation is the hard reality, not a set of imperfect measures for a central tendency. Means and medians are the abstractions. Therefore, I looked at the mesothelioma statistics quite differently - and not only because I am an optimist who tends to see the doughnut instead of the hole, but primarily because I know that variation itself is the reality. I had to place myself amidst the variation.
When I learned about the eight-month median, my first intellectual reaction was: fine, half the people will live longer; now what are my chances of being in that half. I read for a furious and nervous hour and concluded, with relief: damned good. I possessed every one of the characteristics conferring a probability of longer life: I was young; my disease had been recognized in a relatively early stage; I would receive the nation's best medical treatment; I had the world to live for; I knew how to read the data properly and not despair.
Another technical point then added even more solace. I immediately recognized that the distribution of variation about the eight-month median would almost surely be what statisticians call "right skewed." (In a symmetrical distribution, the profile of variation to the left of the central tendency is a mirror image of variation to the right. In skewed distributions, variation to one side of the central tendency is more stretched out - left skewed if extended to the left, right skewed if stretched out to the right.) The distribution of variation had to be right skewed, I reasoned. After all, the left of the distribution contains an irrevocable lower boundary of zero (since mesothelioma can only be identified at death or before). Thus, there isn't much room for the distribution's lower (or left) half - it must be scrunched up between zero and eight months. But the upper (or right) half can extend out for years and years, even if nobody ultimately survives. The distribution must be right skewed, and I needed to know how long the extended tail ran - for I had already concluded that my favorable profile made me a good candidate for that part of the curve.
The distribution was indeed, strongly right skewed, with a long tail (however small) that extended for several years above the eight month median. I saw no reason why I shouldn't be in that small tail, and I breathed a very long sigh of relief. My technical knowledge had helped. I had read the graph correctly. I had asked the right question and found the answers. I had obtained, in all probability, the most precious of all possible gifts in the circumstances - substantial time. I didn't have to stop and immediately follow Isaiah's injunction to Hezekiah - set thine house in order for thou shalt die, and not live. I would have time to think, to plan, and to fight.
One final point about statistical distributions. They apply only to a prescribed set of circumstances - in this case to survival with mesothelioma under conventional modes of treatment. If circumstances change, the distribution may alter. I was placed on an experimental protocol of treatment and, if fortune holds, will be in the first cohort of a new distribution with high median and a right tail extending to death by natural causes at advanced old age.
It has become, in my view, a bit too trendy to regard the acceptance of death as something tantamount to intrinsic dignity. Of course I agree with the preacher of Ecclesiastes that there is a time to love and a time to die - and when my skein runs out I hope to face the end calmly and in my own way. For most situations, however, I prefer the more martial view that death is the ultimate enemy - and I find nothing reproachable in those who rage mightily against the dying of the light.
The swords of battle are numerous, and none more effective than humor. My death was announced at a meeting of my colleagues in Scotland, and I almost experienced the delicious pleasure of reading my obituary penned by one of my best friends (the so-and-so got suspicious and checked; he too is a statistician, and didn't expect to find me so far out on the right tail). Still, the incident provided my first good laugh after the diagnosis. Just think, I almost got to repeat Mark Twain's most famous line of all: the reports of my death are greatly exaggerated.
Postscript By Steve Dunn
Many people have written me to ask what became of Stephen Jay Gould. Sadly, Dr. Gould died in May of 2002 at the age of 60. Dr. Gould lived for 20 very productive years after his diagnosis, thus exceeding his 8 month median survival by a factor of thirty! Although he did die of cancer, it apparently wasn't mesothelioma, but a second and unrelated cancer.
In March 2002, Dr. Gould published his 1342 page "Magnum Opus", The Structure of Evolutionary Theory. It is fitting that Gould, one of the world's most prolific scientists and writers, was able to complete the definitive statement of his scientific work and philosophy just in time. That text is far too long and dense for almost any layman - but the works of Stephen Jay Gould will live on. Especially I hope, The Median Isn't The Message .
Duncan
The Median Isn't the Message by Stephen Jay Gould
My life has recently intersected, in a most personal way, two of Mark Twain's famous quips. One I shall defer to the end of this essay. The other (sometimes attributed to Disraeli), identifies three species of mendacity, each worse than the one before - lies, damned lies, and statistics.
Consider the standard example of stretching the truth with numbers - a case quite relevant to my story. Statistics recognizes different measures of an "average," or central tendency. The mean is our usual concept of an overall average - add up the items and divide them by the number of sharers (100 candy bars collected for five kids next Halloween will yield 20 for each in a just world). The median, a different measure of central tendency, is the half-way point. If I line up five kids by height, the median child is shorter than two and taller than the other two (who might have trouble getting their mean share of the candy). A politician in power might say with pride, "The mean income of our citizens is $15,000 per year." The leader of the opposition might retort, "But half our citizens make less than $10,000 per year." Both are right, but neither cites a statistic with impassive objectivity. The first invokes a mean, the second a median. (Means are higher than medians in such cases because one millionaire may outweigh hundreds of poor people in setting a mean; but he can balance only one mendicant in calculating a median).
The larger issue that creates a common distrust or contempt for statistics is more troubling. Many people make an unfortunate and invalid separation between heart and mind, or feeling and intellect. In some contemporary traditions, abetted by attitudes stereotypically centered on Southern California, feelings are exalted as more "real" and the only proper basis for action - if it feels good, do it - while intellect gets short shrift as a hang-up of outmoded elitism. Statistics, in this absurd dichotomy, often become the symbol of the enemy. As Hilaire Belloc wrote, "Statistics are the triumph of the quantitative method, and the quantitative method is the victory of sterility and death."
This is a personal story of statistics, properly interpreted, as profoundly nurturant and life-giving. It declares holy war on the downgrading of intellect by telling a small story about the utility of dry, academic knowledge about science. Heart and head are focal points of one body, one personality.
In July 1982, I learned that I was suffering from abdominal mesothelioma, a rare and serious cancer usually associated with exposure to asbestos. When I revived after surgery, I asked my first question of my doctor and chemotherapist: "What is the best technical literature about mesothelioma?" She replied, with a touch of diplomacy (the only departure she has ever made from direct frankness), that the medical literature contained nothing really worth reading.
Of course, trying to keep an intellectual away from literature works about as well as recommending chastity to Homo sapiens, the sexiest primate of all. As soon as I could walk, I made a beeline for Harvard's Countway medical library and punched mesothelioma into the computer's bibliographic search program. An hour later, surrounded by the latest literature on abdominal mesothelioma, I realized with a gulp why my doctor had offered that humane advice. The literature couldn't have been more brutally clear: mesothelioma is incurable, with a median mortality of only eight months after discovery. I sat stunned for about fifteen minutes, then smiled and said to myself: so that's why they didn't give me anything to read. Then my mind started to work again, thank goodness.
If a little learning could ever be a dangerous thing, I had encountered a classic example. Attitude clearly matters in fighting cancer. We don't know why (from my old-style materialistic perspective, I suspect that mental states feed back upon the immune system). But match people with the same cancer for age, class, health, socioeconomic status, and, in general, those with positive attitudes, with a strong will and purpose for living, with commitment to struggle, with an active response to aiding their own treatment and not just a passive acceptance of anything doctors say, tend to live longer. A few months later I asked Sir Peter Medawar, my personal scientific guru and a Nobelist in immunology, what the best prescription for success against cancer might be. "A sanguine personality," he replied. Fortunately (since one can't reconstruct oneself at short notice and for a definite purpose), I am, if anything, even-tempered and confident in just this manner.
Hence the dilemma for humane doctors: since attitude matters so critically, should such a sombre conclusion be advertised, especially since few people have sufficient understanding of statistics to evaluate what the statements really mean? From years of experience with the small-scale evolution of Bahamian land snails treated quantitatively, I have developed this technical knowledge - and I am convinced that it played a major role in saving my life. Knowledge is indeed power, in Bacon's proverb.
The problem may be briefly stated: What does "median mortality of eight months" signify in our vernacular? I suspect that most people, without training in statistics, would read such a statement as "I will probably be dead in eight months" - the very conclusion that must be avoided, since it isn't so, and since attitude matters so much.
I was not, of course, overjoyed, but I didn't read the statement in this vernacular way either. My technical training enjoined a different perspective on "eight months median mortality." The point is a subtle one, but profound - for it embodies the distinctive way of thinking in my own field of evolutionary biology and natural history.
We still carry the historical baggage of a Platonic heritage that seeks sharp essences and definite boundaries. (Thus we hope to find an unambiguous "beginning of life" or "definition of death," although nature often comes to us as irreducible continua.) This Platonic heritage, with its emphasis in clear distinctions and separated immutable entities, leads us to view statistical measures of central tendency wrongly, indeed opposite to the appropriate interpretation in our actual world of variation, shadings, and continua. In short, we view means and medians as the hard "realities," and the variation that permits their calculation as a set of transient and imperfect measurements of this hidden essence. If the median is the reality and variation around the median just a device for its calculation, the "I will probably be dead in eight months" may pass as a reasonable interpretation.
But all evolutionary biologists know that variation itself is nature's only irreducible essence. Variation is the hard reality, not a set of imperfect measures for a central tendency. Means and medians are the abstractions. Therefore, I looked at the mesothelioma statistics quite differently - and not only because I am an optimist who tends to see the doughnut instead of the hole, but primarily because I know that variation itself is the reality. I had to place myself amidst the variation.
When I learned about the eight-month median, my first intellectual reaction was: fine, half the people will live longer; now what are my chances of being in that half. I read for a furious and nervous hour and concluded, with relief: damned good. I possessed every one of the characteristics conferring a probability of longer life: I was young; my disease had been recognized in a relatively early stage; I would receive the nation's best medical treatment; I had the world to live for; I knew how to read the data properly and not despair.
Another technical point then added even more solace. I immediately recognized that the distribution of variation about the eight-month median would almost surely be what statisticians call "right skewed." (In a symmetrical distribution, the profile of variation to the left of the central tendency is a mirror image of variation to the right. In skewed distributions, variation to one side of the central tendency is more stretched out - left skewed if extended to the left, right skewed if stretched out to the right.) The distribution of variation had to be right skewed, I reasoned. After all, the left of the distribution contains an irrevocable lower boundary of zero (since mesothelioma can only be identified at death or before). Thus, there isn't much room for the distribution's lower (or left) half - it must be scrunched up between zero and eight months. But the upper (or right) half can extend out for years and years, even if nobody ultimately survives. The distribution must be right skewed, and I needed to know how long the extended tail ran - for I had already concluded that my favorable profile made me a good candidate for that part of the curve.
The distribution was indeed, strongly right skewed, with a long tail (however small) that extended for several years above the eight month median. I saw no reason why I shouldn't be in that small tail, and I breathed a very long sigh of relief. My technical knowledge had helped. I had read the graph correctly. I had asked the right question and found the answers. I had obtained, in all probability, the most precious of all possible gifts in the circumstances - substantial time. I didn't have to stop and immediately follow Isaiah's injunction to Hezekiah - set thine house in order for thou shalt die, and not live. I would have time to think, to plan, and to fight.
One final point about statistical distributions. They apply only to a prescribed set of circumstances - in this case to survival with mesothelioma under conventional modes of treatment. If circumstances change, the distribution may alter. I was placed on an experimental protocol of treatment and, if fortune holds, will be in the first cohort of a new distribution with high median and a right tail extending to death by natural causes at advanced old age.
It has become, in my view, a bit too trendy to regard the acceptance of death as something tantamount to intrinsic dignity. Of course I agree with the preacher of Ecclesiastes that there is a time to love and a time to die - and when my skein runs out I hope to face the end calmly and in my own way. For most situations, however, I prefer the more martial view that death is the ultimate enemy - and I find nothing reproachable in those who rage mightily against the dying of the light.
The swords of battle are numerous, and none more effective than humor. My death was announced at a meeting of my colleagues in Scotland, and I almost experienced the delicious pleasure of reading my obituary penned by one of my best friends (the so-and-so got suspicious and checked; he too is a statistician, and didn't expect to find me so far out on the right tail). Still, the incident provided my first good laugh after the diagnosis. Just think, I almost got to repeat Mark Twain's most famous line of all: the reports of my death are greatly exaggerated.
Postscript By Steve Dunn
Many people have written me to ask what became of Stephen Jay Gould. Sadly, Dr. Gould died in May of 2002 at the age of 60. Dr. Gould lived for 20 very productive years after his diagnosis, thus exceeding his 8 month median survival by a factor of thirty! Although he did die of cancer, it apparently wasn't mesothelioma, but a second and unrelated cancer.
In March 2002, Dr. Gould published his 1342 page "Magnum Opus", The Structure of Evolutionary Theory. It is fitting that Gould, one of the world's most prolific scientists and writers, was able to complete the definitive statement of his scientific work and philosophy just in time. That text is far too long and dense for almost any layman - but the works of Stephen Jay Gould will live on. Especially I hope, The Median Isn't The Message .
Thursday, September 11, 2008
Arthoscopic Knee Surgery Fails the Test
Here is an item on knee surgery from the Wall Street Journal Health Blog. It was also mentioned on NPR today.
Duncan
September 11, 2008, 8:29 am
Knee Surgery No Help for Arthritis
Posted by Jacob Goldstein
Surgeons take it as an article of faith that a chance to cut is a chance to cure. So it's a pretty big deal when a study clearly shows that a common surgery doesn't actually help certain patients. Even more so if the study is confirming similar results from a previous study.
That's what happened this week, when the New England Journal of Medicine published a study that showed arthroscopic surgery doesn't provide any benefit for moderate to severe arthritis of the knee.
Researchers randomly assigned nearly 200 patients to receive either surgery, drugs and physical therapy, or drugs and physical therapy alone. Three months later, patients who had surgery had slightly less pain than those who did not. But there was no significant difference between the two groups at six months, one year or two years. The difference at two years was the main measure the researchers looked at.
A 2002 study had similar results.
http://snipurl.com/3pdn9
Duncan
September 11, 2008, 8:29 am
Knee Surgery No Help for Arthritis
Posted by Jacob Goldstein
Surgeons take it as an article of faith that a chance to cut is a chance to cure. So it's a pretty big deal when a study clearly shows that a common surgery doesn't actually help certain patients. Even more so if the study is confirming similar results from a previous study.
That's what happened this week, when the New England Journal of Medicine published a study that showed arthroscopic surgery doesn't provide any benefit for moderate to severe arthritis of the knee.
Researchers randomly assigned nearly 200 patients to receive either surgery, drugs and physical therapy, or drugs and physical therapy alone. Three months later, patients who had surgery had slightly less pain than those who did not. But there was no significant difference between the two groups at six months, one year or two years. The difference at two years was the main measure the researchers looked at.
A 2002 study had similar results.
http://snipurl.com/3pdn9
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