Cancer Survival Rates Can Be Misleading

The British press is having a field day (see here and here) attacking their single-payer National Health Service in the wake of a new report showing that cancer survival rates in Great Britain are the lowest in Europe. Lancet Oncology, which published the study, editorially called for "a fundamental reassessment of the ways in which the NHS operates."

How bad is cancer care in the home of socialized medicine? The measure used in the Eurocare-4 study was survival among those diagnosed with cancer, which is defined as those diagnosed with the disease who survive five years. Cancer survival rates in England in 2003 were 52.7 per cent for women and 44.8 per cent for men. This lagged behind every other country in the European Union except Slovenia, Poland and the Czech Republic.

Guess who would sit atop the list if part of Europe? It's the U.S., where 62.9 per cent of female cancer patients and 66.3 per cent of male patients survive five years after diagnosis.

But wait a minute. I don't want to know just about survival. I also want to know what my chances are of getting cancer in the first place. It's only when we know both numbers that we get a full portrait of where the greatest risk lies.

International comparisons of incidence are not easily obtainable, but by going to Cancer Research UK and the National Cancer Institute's statistical branch, I was able to compare overall cancer incidence rates in the two countries.

Guess what. Americans contract cancer at a 27 percent higher rate! There were 470 diagnoses of cancer per 100,000 in the U.S. in 2004 compared to just 370 cases per 100,000 residents in the UK. (I also looked up those wine-sipping French with their single-payer, national health care system. They suffered just 309 cancers per 100,000 population.)

The higher rates held whether looking at women or men. Males in the U.S. suffered 556 cases per 100,000 population compared to just 408 in the UK. Females in the U.S. contracted 411 cases per 100,000 versus just 348 in he UK.

And when I looked at a different bottom line -- the annual mortality rate and not the five-year survival rate -- what I found was that the British actually do slightly better than we do with just 182 out of 100,000 Brits dying of cancer each year compared to 192 out of every 100,000 Americans.

A cancer epidemiologist would probably explain the data this way: In the U.S., we conduct far more tests, which turn up many more cancers. That in turn leads to higher survival rates because we wind up treating some cancers at an earlier stage. It probably even saves some lives that otherwise would have been lost to the disease.

But there's a downside to all those tests. They have relatively high false positive rates. In other words, they turn up minor cancers that may never have progressed to full-blown neoplasms. Yet, they are treated anyway since determining which ones will progress is impossible at that early stage.

I also suspect that different patterns of diet, exercise, stress, and toxic exposures account for some of the increased cancer rate in the U.S. But international comparisons on those indicators are even harder to come by than comparative data on cancer incidence rates.

So, yes, the British five-year survival rates from cancer are substantially lower than the U.S. But that's not the whole cancer story. This one study shouldn't be used to condemn Great Britain's National Health Service and its policy of going slow in paying for pricey, marginally effective new cancer therapies.

Posted by gooznews at August 22, 2007 01:09 PM