Canada gets high ranking for cancer survival rates
CTV.ca News Staff
Published Wednesday, July 16, 2008 10:55PM EDT
Canada has some of the best cancer survival rates in the world, and doctors are pointing to our much-maligned public health-care system as the reason.
In a report on worldwide cancer survival rates, Canada ranked near the top of the 31 countries studied with an estimate five-year survival rate of 82.5 per cent.
For breast cancer, Cuba had the highest survival rates -- another country with free health care. The United States was second, and Canada was third, with 82 per cent of women surviving at least five years.
"Canadians always tend to complain about our health-care system," Dr. Mary Gospodarowicz, a cancer researcher with Toronto's Princess Margaret Hospital, told CTV News. "But this study shows us that in an independent study done by external bodies, the survival of cancer patients in Canada is among the best in the world."
The U.S. has a five-year survival rate in all the cancers studied of 91.9 per cent, while Europe's is much lower at 57.1 per cent. However, survival rates within the U.S. can vary.
In Canada, the five Canadian provinces included in the study had almost identical results.
"For those five provinces, the survival rate does not differ very greatly from one to the other," said British cancer researcher Prof. Michel Coleman. "That probably indicates the overall effectiveness of universal health care for setting a high standard."
The range of survival rates across the five provinces was quite narrow, from a low of 79.3 per cent in Nova Scotia to a high of 85.4 per cent in British Columbia.
The other provinces studied were Manitoba, Ontario and Saskatchewan.
However, the survival rate for the seventeen regions in the United States that were included in the study ranged from 78 per cent to 90 per cent.
The disparity in survival rates crossed racial lines in the U.S., as well, with white patients having a five-year survival rate of 84.7 per cent and black patients having a survival rate of 70.9 per cent.
The research was conducted by more than 100 scientists, led by Coleman of the Cancer Research UK Cancer Survival Group and the London School of Hygiene and Tropical Medicine.
Researchers compiled data on the five-year survival rates of patients who were diagnosed between 1990 and 1994 and were followed up with until the end of 1999. Breast, colon, rectum and prostate cancer patients were included in the study.
The CONCORD study, a trans-Atlantic comparison of cancer survival, is published in the August edition of the journal The Lancet Oncology.
In the report, data from almost 2 million cancer patients from 31 countries showed that the U.S. has the highest survival rates for breast and prostate cancer, Japan has the highest survival rates for colon and rectal cancers in men and France has the highest survival rates for colon and rectal cancer in women.
Algeria had the lowest survival rates for all cancers included in the study, regardless of whether the patients were male or female.
"Most of the wide global range in survival is probably attributable to differences in access to diagnostic and treatment services," the authors wrote.
Further research is planned on how the stage of the cancer at the time of diagnosis may affect survival rates. As well, the study itself will be updated with data from additional countries.
Cancer survival in five continents: a worldwide population-based study (CONCORD)
Michel P Coleman, Manuela Quaresma, Franco Berrino, Jean-Michel Lutz, Roberta De Angelis, Riccardo Capocaccia, Paolo Baili, Bernard Rachet, Gemma Gatta, Timo Hakulinen, Andrea Micheli, Milena Sant, Hannah K Weir, J Mark Elwood, Hideaki Tsukuma, Sergio Koifman, Gulnar Azevedo e Silva, Silvia Francisci, Mariano Santaquilani, Arduino Verdecchia, Hans H Storm, John L Young, and the CONCORD Working Group
Background: Cancer survival varies widely between countries. The CONCORD study provides survival estimates for 1-9 million adults (aged 15-99 years) diagnosed with a first, primary, invasive cancer of the breast (women), colon, rectum, or prostate during 1990-94 and followed up to 1999, by use of individual tumour records from 101 population-based cancer registries in 31 countries on five continents. This is, to our knowledge, the first worldwide analysis of cancer survival, with standard quality-control procedures and identical analytic methods for all datasets.
Methods: To compensate for wide international differences in general population (background) mortality by age, sex, country, region, calendar period, and (in the USA) ethnic origin, we estimated relative survival, the ratio of survival noted in the patients with cancer, and the survival that would have been expected had they been subject only to the background mortality rates. 2800 life tables were constructed. Survival estimates were also adjusted for differences in the age structure of populations of patients with cancer.
Findings: Global variation in cancer survival was very wide. 5-year relative survival for breast, colorectal, and prostate cancer was generally higher in North America, Australia, Japan, and northern, western, and southern Europe, and lower in Algeria, Brazil, and eastern Europe. CONCORD has provided the first opportunity to estimate cancer survival in 11 states in USA covered by the National Program of Cancer Registries (NPCR), and the study covers 42% of the US population, four-fold more than previously available. Cancer survival in black men and women was systematically and substantially lower than in white men and women in all 16 states and six metropolitan areas included. Relative survival for all ethnicities combined was 2-4% lower in states covered by NPCR than in areas covered by the Surveillance Epidemiology and End Results (SEER) Program. Age-standardised relative survival by use of the appropriate race-specific and state-specific life tables was up to 2% lower for breast cancer and up to 5% lower for prostate cancer than with the census-derived national life tables used by the SEER Program. These differences in population coverage and analytical method have both contributed to the survival deficit noted between Europe and the USA, from which only SEER data have been available until now.
Interpretation: Until now, direct comparisons of cancer survival between high-income and low-income countries have not generally been available. The information provided here might therefore be a useful stimulus for change. The findings should eventually facilitate joint assessment of international trends in incidence, survival, and mortality as indicators of cancer control.