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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 Michel Coleman, the report's principal author and 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 the 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,” Dr. 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,” Dr. 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,” Dr. Coleman said.

John McLaughlin, vice-president of population studies and surveillance for Cancer Care Ontario, called the scope of the project “quite remarkable” and its findings “extremely useful.”

Dr. McLaughlin, who was not involved in the study, said it helps place Canada in the context of the worldwide experience of cancer survival.

“What it does indicate about Canada is that Canada ranks quite favourably for the cancers that they've looked at and that's very good news for us,” he said. “There's still more to be done, but in terms of seeing the success of cancer survival, this is quite good news.”

“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.”