July 16, 2008 -- Where you live plays a role in cancer survival, according to a new study that shows the U.S., Japan, and France recorded the highest survival rates among 31 nations for four types of cancer. Algeria had the lowest survival rates for all four cancers.
"This is the first direct comparison of so many countries as far as I am aware," says Michel Coleman, MD, a professor of epidemiology and vital statistics at the London School of Hygiene and Tropical Medicine and the study's lead author.
While Coleman and other epidemiologists have long known that cancer survival rates vary country by country, and even within a country, the study lends hard numbers to the fact. Still, there were surprises. "I think the surprises were that the range in global survival is really quite wide," Coleman tells WebMD.
"Survival in the USA is high on a global scale but varies quite widely among individual states as well as between blacks and whites within the USA," he tells WebMD.
Cancer Survival by Country
Coleman and colleagues drew on data from nearly 2 million cancer patients, ages 15 to 99, whose medical information was entered into 101 population-based cancer registries in 31 countries. The patients had been diagnosed with one of four cancers: breast, colon, rectum, or prostate cancers during the years 1990-1994. They were followed up to 1999, with the researchers comparing five-year survival rates.
The highest survival rates were found in the U.S. for breast and prostate cancer, in Japan for colon and rectal cancers in men, and in France for colon and rectal cancers in women, Coleman's team reports.
In Canada and Australia, survival was also high for most cancers.
The lowest cancer survival rates for all four cancers were found in Algeria.
Cancer Survival: A Closer Look at the U.S.
Survival rates varied among the 16 states and six metropolitan areas included in the study.
Idaho had the best survival rates for rectal cancer in men and Seattle was highest for rectal cancer in women. Patients in Seattle also had the best survival rates for prostate cancer. For all other cancers studied, patients in Hawaii had the highest survival rates.
Patients in New York City had the lowest survival rates for all four cancers except rectal cancer in both men and women. For those, patients in Wyoming had the lowest survival rate.
A racial gap in survival was evident, with white patients more likely than blacks to survive, especially breast cancer. "The comparison is confirmed right across the USA, in all 16 states," Coleman says of the racial gap.
For the study, the researchers estimated relative survival, adjusting for such factors as wide differences in death rates from country to country and for age.
Cancer Survival Study: Second Opinion
"This is a very good way of presenting data worldwide, using the same method of analysis," says Ahmedin Jemal, PhD, strategic director for cancer occurrence for the American Cancer Society, who reviewed the study for WebMD.
The state-by-state differences in cancer survival rates do not surprise him, he says. "Previous studies have shown differences in treatment for breast cancer, for example, across states." Differences in screening have also been detected, he says, with the percentage of women getting regular mammograms, found to vary widely from state to state.
Coleman and Jemal hope the study results will motivate public health policy makers. "What is required here on a policy level is understanding why those differences occur and remedying those differences so the entire population can benefit from the improvement," Coleman says.
Within the U.S., Jemal says, he is hopeful the report will motivate cancer control program organizers at the state level. Policymakers in a state with lower cancer survival rates could consult with neighboring state policymakers with higher survival rates and adopt some of their programs, he says.
The study is published early online and in the August edition of The Lancet Oncology. Funding was provided by the CDC, the Department of Health in London, and Cancer Research UK in London.