Another study underscoring the futility of screening asymptomatic women for breast cancer has been published, this time in the New England Journal of Medicine. An accompanying commentary with additional analysis by Dr. H. Gilbert Welch (author of Should I Be Tested For Cancer? Maybe Not and Here’s Why) is available here.
The study was carried out in Norway, where everybody is covered by national health insurance, which covers screening mammograms for all women between the ages of 50 and 69. The study took advantage of the fact that screening mammograms were not made available to all parts of the country at the same time – the program was instituted in a staggered fashion between 1996 and 2005, with screening becoming available in some of Norway’s 19 counties before others. This allowed for researchers to separate any reduction of breast cancer mortality due to screening mammograms from that due to other causes, such as increased awareness and treatment.
All Norwegian women who received a diagnosis of invasive breast cancer between the years 1986 through 2005 were included in the study. These women were divided into four groups: 1) women living in counties in which screening was available between 1996 and 2005; 2) women living in counties in which screening was not available during the same time period; 3) a historical-comparison from the period 1986-1995 from the same counties as in group (1); and 4) another historical-comparison group from the period 1986-1995 from the same counties as in group (2).
Direct comparison between the first and the second groups was not possible, since the rates of breast cancer varied widely between different counties. Hence the role of the historical-comparison groups. Any reduction in mortality between the non-screening group and its historical comparison counterpart obviously could not have been due to screening, and must have been due to advances in awareness, treatment, and the like. The reduction in mortality due to screening was equal to the reduction in the death rate in the screening group compared to its historical counterpart, minus the reduction the death rate between the non-screening group and its historical counterpart.
The data showed that screening mammograms reduced a woman’s chances of dying of breast cancer by one in 2,500 – a result even punier than the figure of one in 1,339 reported by the US Preventive Services Task Force, or the figure of one in 2,000 reported by the Cochrane Collaboration. The one in 2,500 figure was found not to be statistically significant – in plain English, there is a high probability that the miniscule difference between the control and experimental groups could have arisen by chance. But Hell, I don’t need statistical tests to tell me that a one in 2,500 reduction in risk is not worth bothering with.
Nortin M. Hadler, M.D., author of Worried Sick, says that anything less than a one in twenty reduction in the risk of death or some other hard clinical outcome is not worth bothering with, but he’s made of sterner stuff than I am. I’ll take a one in a hundred reduction. But one in 2,500? Come on, now.
But even that doesn’t tell the full story. Breast cancer tends to be a disease of old age, or at least of late middle-age, a time when the death rate for a multitude of causes increases. What difference does it make if you die of breast cancer at the age of 70, or you die of something else at the exact same time? The only statistic that means anything to you is the OVERALL death rate. Only one of the three studies cited above – the one by the Cochrane Collaboration – looked at all-cause mortality, and found NO DIFFERENCE in the death rate between women who got regular mammograms, and those that did not. In plain English, there’s no data that shows that screening mammograms reduces a woman’s chance of dying prematurely.
This really shouldn’t come as a surprise to anybody. Not all cancers are created equal. Some “cancers” grow so slowly that they never bother you until you die of something unrelated. Others grow so rapidly that, even if detected before symptoms appear by the new screening technologies, kill you anyway. The whole idea of screening for cancer was based on the hope – that’s all it ever was, a hope – that there were cancers which were so rapidly-growing which were incurable if you waited for symptoms to appear, but which were so slow-growing that, if detected before that, could be cured. There is no convincing evidence that such cancers even exist. If they do, they are so rare that screening doesn’t make a difference in the death rate.
According to this article in the Washington Post, American Cancer Society President Otis Brawley defended his organization’s position on screening mammography in a press release (not available on the ACS website as of this posting). “The total body of the science supports the fact that regular mammography is an important part of a woman's preventive health care,” he huffed. “Following the American Cancer Society's guidelines for the early detection of breast cancer improves the chances that breast cancer can be diagnosed at an early stage and treated successfully.”
As if just saying that makes it true.
I’d like to know what data he based his opinions on. I’d also like to know how much of his salary is paid for by the manufacturers of medical devices, like, oh, say, the X-ray machines used in mammography.
Dr. Brawley also opined that a longer study might have revealed a significant benefit to mammography. Well, sure – anything might happen. But if a multi-year study involving over 40,000 women with invasive breast cancer failed to reveal any significant benefits from screening mammography, then it’s obvious any benefits it “might” produce must be tiny indeed.
Besides, on whom is the burden of proof here? I submit the burden of proof ought to be on doctors so demonstrate the interventions they are foisting on us have a reasonable likelihood of doing us some good – especially when they are claiming authority over people who are not even sick (women who undergo screening mammography, by definition, do not have symptoms of breast cancer).
There’s more than just money at stake here. A diagnosis of cancer can ruin your life. It can bankrupt you, it can render you permanently uninsurable and unemployable. What’s more, being treated for breast cancer can kill you. That’s a Hell of a price to pay if you were one of the ones whose “cancer” was a tiny, slow-growing neoplasm which never would have bothered you until you died of something completely unrelated.
There’s even more at stake than that. What’s at stake here is an entire world view. Do we want to see ourselves as creatures who were born with everything we need (most of us, anyway) to stay strong and healthy into our seventies, with minimal help from the medical profession, or do we want to see ourselves as fragile, disease-ridden time bombs who must endlessly perform rituals like mammograms to keep the specter of death at bay?
Obviously, I don’t have to worry about dying of breast cancer. You may be wondering how I feel about interventions such as prostate screening and colon cancer screening. Fair question. The answer is simple: I will not avail myself of such procedures. Not willingly, anyway. But it looks as if I may not have a choice, at least not unless some of the more odious provisions of health care “reform” are not overturned.
If and when I return to the United States from Africa, I am going to be forced to hand over hundreds or thousands of dollars a year to the health insurance industry, and, with my fiftieth birthday looming, I suppose that before I am allowed to do that I shall have to submit to a colonoscopy – even though there’s no data that shows that screening colonoscopy is correlated with a significant reduction in all-cause mortality.
I’m telling you, if being sodomized by a fiber-optic cable is the price I’ll have to pay for the increasingly dubious privilege of calling myself an American citizen, I just may decide to stay in Africa for good.
Does that shock you? Well, know that not everybody considers it a privilege to be treated like a lab rat, whose body can be poked and prodded and invaded with impunity by the medical profession. Come to think of it, the more I learn about these matters, and the more I realize just how much harm and how little good is done by our Medical-Industrial Complex, the harder it becomes for me to justify treating lab rats that way.
Grim Reaper illustration via National Library of Medicine
All other photos via Wikimedia Commons