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The Globe And Mail
March 26, 2009

Found: a c-word for cancer
By André Picard

There is a Run for the Cure, a Ride to Conquer Cancer and a Weekend to End Breast Cancer, among others; these fundraising events have catchy names that tell of lofty goals.

But how much cancer can we really cure and conquer, and can we realistically hope to eradicate breast cancer, or any other cancer for that matter?

Generally, after diagnosis and treatment of cancer, health professionals speak of survival, not cure. The success of treatments is usually viewed through the prism of five-year survival.

Among Canadians, the five-year relative survival rate for all cancers combined is 59 per cent. This means that those diagnosed with cancer are 59 per cent as likely to live for another five years as are comparable members of the general population who are cancer-free.

Five-year survival rates vary widely depending on type of cancer, from a dismal 6 per cent for pancreatic cancer to a remarkable 95 per cent for thyroid and testicular cancer.

For the most common cancers, the rates vary too: lung, 16 per cent; colorectal, 60 per cent; breast, 86 per cent, and prostate, 91 per cent.

But these numbers do not distinguish between those who will die of cancer and those who will not.

With advances in early detection, treatment and care, patients don’t merely survive cancer any more – they can be cured.

Yet many clinicians and researchers avoid the c-word, cure, because it implies some sort of miracle that came about through divine intervention. Speaking of cures can also give some patients unrealistic expectations.

But being cured simply means that, after treatment, a patient’s life expectancy is identical to a comparable member of the general population. Put another way, their relative survival rate is 100 per cent for five years and beyond.

This means that they will die of something other than their primary cancer.

New research, published this week in the European Journal of Cancer, offers the most detailed numbers yet on how many people are cured of cancer. Not surprisingly, the numbers vary widely by type of cancer and by country.

Across the 23 European countries participating in the Eurocare-4 study, 4 to 10 per cent of lung cancer patients were cured; between 9 and 27 per cent were cured of stomach cancer; 25 to 49 per cent were cured of colorectal cancer, and 55 to 73 per cent were cured of breast cancer.

In the latter two, high cure rates were attributed principally to screening, the implication being that when a cancer is diagnosed early, it is more treatable and hence more curable.

(The problem with early detection is that it creates “lead-time bias” – meaning people survive longer after diagnosis, but with no improvement in life expectancy. But the European numbers that focus on cure, rather than five-year survival, suggest genuine progress in controlling cancer.)

The research also shows, not too surprisingly, that survival and cure rates in the elderly (defined as those over 70) with cancer were worse than among the middle-aged (55 to 69) and that women of all ages respond better to cancer treatment than men do, which suggests that sex hormones play a role.

Finally, the Eurocare-4 study – with data on 13.5 million cancer patients collected since 1978, it is one of the most extensive data collections in the world – demonstrates that survival and cure rates have risen steadily for two decades, offering a lot of hope to those diagnosed with cancer.

Last year, an estimated 166,400 Canadians were diagnosed with cancer and about 73,800 died of cancer. About 40 per cent of women and 45 per cent of men will develop cancer during their lifetimes, and about 1 in 4 Canadians can expect to die of it.

That cancer numbers continue to rise is, in some ways, a success story. After all, cancer is largely a disease (or, more precisely a vast array of diseases) of aging. A lot of people now live long enough to get cancer.

The new data remind us that, particularly at a younger age, we can cure many forms of cancer rather effectively.

But they should not distract us from the fact that we can also prevent a lot of cancer, and prevention is a lot more effective (not to mention more pleasant) than treatment.

A new poll commissioned by the Canadian Partnership Against Cancer shows that close to half of Canadians (43 per cent) believe a person’s chance of developing cancer is based largely on luck of the draw.

In fact, cancer comes about as a combination of genetics, lifestyle and socio-economic circumstance.

Just as a significant percentage of cancer can be cured if caught early, a good chunk can be prevented through lifestyle choices: Between one-quarter and one-third of all cancers worldwide can be prevented through a healthy diet, regular physical activity and a healthy body weight, according to a recent international study.

So while Canadians walk, run and bike for a cure, they also need to remember they can walk, run and bike to prevent cancer in the first place.

Prevention, treatment and cure should not be distinct entities, but parts of the same continuum of care, one that requires infrastructure, investment and sound public policies.

Sourece: The Globe and Mail