TORONTO - Canada consistently ranks near the top in a worldwide estimate of five-year survival rates for cancer patients, according to an international study, which found huge variations from country to country and even within some nations' borders.

The CONCORD study directly compares survival rates in 31 countries for four malignancies - breast cancer in women, prostate cancer, colorectal cancer in men and colorectal cancer in women.

Canada ranked second overall in patient survival for breast cancer, third for prostate and for colorectal cancer in women, and sixth for colorectal cancer in men, says the study, published online and in the August edition of The Lancet Oncology.

"Canada is an interesting example," said principal author Dr. Michel Coleman, a professor of epidemiology and vital statistics at the London School of Hygiene and Tropical Medicine.

"What we think is quite striking is that for all of these cancers, the survival in Canada is high and pretty uniform," he said. "There isn't much difference between the Canadian provinces."

The study included data from cancer registries in British Columbia, Manitoba, Saskatchewan, Ontario and Nova Scotia, representing 58 per cent of Canada's population.

"My interpretation of that, and it may be wrong, is that it suggests fairly uniform access to a high standard of health care," Coleman said Wednesday from Bulgaria, where he was vacationing. "Because it's not just that the survival is pretty similar; it's that it's pretty high on a global scale."

He noted that a similar pattern holds for Australia, which has a universal health-care system similar to Canada's.

The best survival rates were recorded by the United States for breast and prostate cancer, by Japan for colorectal cancer in men and by France for colorectal cancer in women. (Cuba actually topped the charts for breast and women's colorectal cancer, but the authors suggest problems with data quality may have led to overestimates.)

While the United States boasted the best or among the best survival rates overall, within its borders not all cancer patients fared equally. The study found five-year survival for blacks lagged behind that of whites, suggesting there may be discrepancies in diagnosis and treatment between the two groups.

Of all the countries, Algeria had by far the lowest survival for all four malignancies studied.

To conduct the study, described by Coleman as a massive undertaking, more than 100 researchers collected survival data for the four common cancers, covering almost two million patients among a total population of about 300 million people in the 31 countries. Patients were diagnosed in 1990 to 1994 and followed to the end of 1999.

"The objective was to find out if we could examine the global range in survival in the same way as the global pattern for cancer occurrence and deaths from cancer have been reported for up to 40 years," Coleman said.

"We knew what the global patterns for cancer and death from cancer were. What we didn't know was the range of survival worldwide."

The researchers discovered that range was wider than suspected.

"And it's that kind of information, concrete information, which enables politicians and health-care planners, but also patients, to understand what the situation is and take appropriate decisions in doing something about it," Coleman said.

Co-author Dr. Mark Elwood, vice-president of family and community oncology at the B.C. Cancer Agency, said data from the study is important for improving cancer care at home and around the globe.

"Cancer is a worldwide disease and the treatment and management of cancer is a worldwide process," he said from Vancouver. "And we're all conscious of what's happening elsewhere in the world. We're conscious of differences in approach, different methods of health-care management, as well as different treatments."

"So it's very important to know whether the patients we're dealing with - the patients in our own community - are having outcomes which are comparable to those in the rest of the world. We can learn a lot from that process."

Elwood said Canada could look to countries with higher survival rates to see what they might be doing better.

"And similarly, if there are places that aren't doing as well, we don't just feel superior about it. We try to see whether on a worldwide basis we can help: is there a way in which these people can be helped to improve?"

Dr. John McLaughlin, vice-president of population studies and surveillance for Cancer Care Ontario, agreed the study's findings are "extremely useful."

"If you can't measure something, you can't improve it ... knowing where we do measure ... is the beginning of us being able to improve on it for every program related to cancer."

For instance, the study shows the Canadian survival rate for colorectal cancer in women is higher than it is for men, although both are far too low, said McLaughlin, who was not involved in the research.

He suggested the survival gap could reflect the fact that more women than men seek testing for colorectal cancer, perhaps resulting in earlier diagnosis that permits more effective treatment.

Whatever the reason, the findings underscore the need for widespread colorectal cancer screening programs for both men and women, he said, as well as ongoing campaigns to encourage their use.

"Clearly we have to get colorectal cancer outcomes and survival rates up to a better level than where they are now. It's too common, too deadly and it's a very serious problem in Ontario and for all of Canada."

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