WEDNESDAY, Jan. 31, 2018 (HealthDay News) -- Cancer survival rates are improving worldwide, but poorer countries are seeing less improvement than wealthier ones, a new study shows.
Researchers analyzed data from 2000 to 2014 to assess five-year cancer survival rates among 37.5 million children and adults diagnosed with one of 18 common cancers. These patients were from 71 countries and territories.
After taking into account a number of factors, the investigators found that survival for most of the cancers included in the study has been consistently high over the last 15 years in the United States, Canada, Australia, New Zealand, Finland, Norway, Iceland and Sweden.
But poorer nations have seen fewer gains.
For example, among women diagnosed with breast cancer in the United States and Australia between 2010 and 2014, five-year survival hit 90 percent, compared to only 66 percent for women diagnosed in India.
And brain tumor survival in children improved in many countries, but five-year survival is twice as high in Denmark and Sweden (around 80 percent) than it is in Mexico and Brazil (less than 40 percent) for children diagnosed as recently as 2014.
And while deadly cancers such as lung and liver cancer still have high death rates in both high- and low-income countries, survival rates have improved in several nations.
Five-year survival for liver cancer rose more than 10 percentage points in Korea (11 percent to 27 percent), Sweden (5 percent to 17 percent), Portugal (8 percent to 19 percent), and Norway (6 percent to 19 percent).
Five-year survival for lung cancer increased by 5 to 10 percentage points in 21 countries including the United Kingdom (7 percent to 13 percent) between 1995 and 2014, with most progress seen in China (8 percent to 20 percent), Japan (23 percent to 33 percent), and Korea (10 percent to 25 percent).
The study also found significant variation worldwide in five-year survival among children diagnosed with the most common type of childhood cancer, acute lymphoblastic leukemia. Survival rates were more than 90 percent in the United States, Canada and nine European countries, but they were below 60 percent in China, Mexico and Ecuador.
The findings were published Jan. 30 in the journal The Lancet.
"Despite improvements in awareness, services and treatments, cancer still kills more than 100,000 children every year worldwide," said study co-author Michel Coleman, a professor from the London School of Hygiene and Tropical Medicine.
"If we are to ensure that more children survive cancer for longer, we need reliable data on the cost and effectiveness of health services in all countries, to compare the impact of strategies in managing childhood cancer," Coleman said in a journal news release.
The U.S. National Cancer Institute has more on .