Sunday, July 12, 2009

Do we do better in the US on prostate cancer?

Four Pinocchios for Recidivist Rudy - Fact Checker:

This is not about Rudy Giuliani, he's irreleveant, but this is about the mythology that remains in the World of Fox about poor outcomes elsewhere. Somebody brought this one up recently (prostate Ca) so I put this here for future reference.

"Let's begin by deconstructing the original Giuliani claim, featured in a campaign ad in New Hampshire. It rests on a crude statistical calculation by his medical adviser, David Gratzer, on the basis of a 2000 study by a pair of health experts from Johns Hopkins university. According to Gratzer, '49 Britons per 100,000 were diagnosed with prostate cancer, and 28 per 100,000 died of it. This means that 57 percent of Britons diagnosed with prostate cancer died of it; and consequently, that just 43 percent survived.'

There are several problems with this line of reasoning, according to health experts.

In order to make statistically valid comparisons in epidemiology, it is necessary to track the same population. Because prostate cancer is a slow-developing tumor, it is probable that the Britons who died of prostate cancer in 2000 contracted the disease 15 years earlier. They represent an entirely different cohort of cancer sufferers than those who were diagnosed with the disease in 2000. The number of Britons diagnosed with the disease is itself a subset of the number of Britons with the disease.

'You would get an F in epidemiology at Johns Hopkins if you did that calculation,' said Johns Hopkins professor Gerard Anderson, whose 2000 study 'Multinational Comparisons of Health Systems Data' has been cited by Gratzer as a source for his statistics. 'Numerators and denominators have to be the same population.'

Five-year prostate cancer survival rates are higher in the United States than in Britain but, according to Howard Parnes of the National Cancer Institute, this is largely a statistical illusion. Americans are screened for the disease earlier and more systematically than Britons. If you are detected with prostate cancer symptoms at age 58 in year one of a disease that takes fifteen years to kill you, your chances of surviving another five years (until the age of 63) are obviously much higher than if your cancer is detected in year eleven, at the age of 68. Both Anderson and Parnes say that it is impossible, on the basis of the available data, to conclude that Americans have a significantly better chance of surviving prostate cancer than Britons.

Whether or not early screening actually reduces mortality from prostate cancer is the subject of much controversy among researchers, both in the United States and Europe. According to Otis Brawley, chief medical officer for the American Cancer Society, "at least 50 percent of men diagnosed with prostate cancer don't need to be treated. The problem is that we can't figure out which men need treatment, and which don't."

In an attempt to figure out if screening for prostate cancer does indeed save lives, the National Cancer Institute has been following 70,000 men since 1992, but has yet to a firm conclusion, Brawley said. Half of the men in the sample are being screened and the other half are not being screened. An August 2007 NCI report said it was still unclear whether "earlier detection and consequent earlier treatment" led to "any change in the natural history and outcome of the disease." Screening can lead to "over-treatment" which can in turn result in undesirable side effects such as erectile dysfunction and incontinence.

"This is getting completely ridiculous," e-mailed Giuliani spokesman Jason Miller. "You are still not getting it. The point the mayor has made is that privatized medicine is better than socialized medicine. If you can find one person who said they'd rather be treated for prostate cancer in the UK instead of the US, we'd like to meet them."

UPDATE WEDNESDAY 4:30 P.M.: Reader Jim Crowder asked an interesting question this morning, in response to Dr. Brawley's statement that at least 50 per cent of men diagnosed with prostate cancer "don't need to be treated." Crowder asked, "OK, If I am in the 1/2 group that would benefit by earlier treatment, wouldn't I rather be in the US and receive it? In fact I have received treatment."

I [Fact Checker] asked Dr Brawley to respond. Here is what he says:

We know that at least half of the screened and detected do not need treatment and any treatment they get can only give them side effects of treatment, including a 0.5% to 1% chance of death from treatment.We do not know that we benefit the other half who have a disease that is destined to disrupt their life by causing symptoms and in many death. Indeed some of our clinical treatment studies are designed to figure out whether we cure those who need to be cured.

Connecticut versus Washinginton State comparisons show that men in Washington State have a much higher risk of prostate cancer diagnosis and treatment and side effects of treatment, but have the same risk of death as men in Connecticut. In several papers, [including] one by me, this has been attributed to the higher rates of screening in Washington compared to Connecticut. Both have had the same decline in mortality rates.

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