Five-year cancer survival rates are increasing globally, but disparities exist between regions, according to results from the CONCORD-3 global cancer surveillance program published in The Lancet. CONCORD-3 is the largest international study of cancer survival trends, including data on more than 37.5 million patients diagnosed with cancer between 2000 and 2014.
Participating countries were home to two-thirds of the world’s population in 2014, according to Claudia Allemani, PhD, of the Department of Non-Communicable Disease Epidemiology at the London School of Hygiene & Tropical Medicine, and co-authors.
The study included data from 322 population-based cancer registries of 71 countries and territories; 47 of these registries covered 100 percent of the population. The analysis included data on 18 common cancers that together represent 75 percent of all diagnosed cancers worldwide, including melanomas and esophageal, stomach, colon, rectal, liver, pancreatic, lung, breast, cervical, ovary, and prostate cancers in adults; and brain tumors, leukemias, and lymphomas in adults and children. Patients with in situ cancer were excluded from survival analyses.
Registries were asked to submit data with follow-up for at least five years or through December 31, 2014, for patients diagnosed between 2010 and 2014. Outcomes data were stratified by time period: 2000 to 2004, 2005 to 2009, and 2010 to 2014.
The authors estimated net survival up to five years after cancer diagnosis, correcting for “background mortality” (other causes of death). This benchmark “has been recognized by clinicians as an index of the effectiveness of the treatment of cancer,” the authors noted.
This study builds on CONCORD-2, which evaluated survival trends for 10 cancers between 1995 and 2014. The CONCORD-3 update includes data on adult and pediatric lymphoma outcomes for the first time.
“Survival for most cancers remains among the highest in the world in the U.S., Canada, Australia, and New Zealand, and in Finland, Iceland, Norway, and Sweden,” the researchers wrote of their findings. However, cancer incidence across the world is continuing to rise. “Prevention is crucial, but implementation has been slow and incomplete, even in high-income countries. Prevention is a long-term strategy, and not all cancers can be prevented.”
Reported here are the findings for hematologic malignancies in adults (defined as 15-99 years) and children included in the CONCORD program.
CONCORD-3 included 1,151,226 adults from 286 registries in 61 countries. During the 2010 to 2014 period, five-year, age-standardized survival rates were highest in France (57.5%) and lowest in Chile (16.5%). Survival rates were within the 30-50 percent range for most countries; however, countries in southeast Asia consistently had survival rates lower than 30 percent.
“It is crucial for national and regional governments to recognize that population-based cancer registries are key policy tools.”
—Claudia Allemani, PhD
Over the 15 years of the CONCORD-3 analysis, five-year survival rates increased by 5 to 10 percent in the following countries: U.S., China, Japan, Singapore, Taiwan; northern Europe (Ireland and the U.K.); southern Europe (Portugal and Spain); eastern Europe (Poland); western Europe (Austria, Belgium, and Germany), and Australia.
Korea, Denmark, the Netherlands, and Norway saw increases greater than 10 percent, and “survival increased dramatically in Lithuania (27.4%), Sweden (26.8%), and the Czech Republic (16.9%),” the authors reported.
The study included 3,011,054 adults from 289 registries in 62 countries. Five-year, age-standardized survival rates ranged from 40-70 percent in most countries, but again, were lower in Asia and Central and South America.
Five-year survival was 70 percent or higher in Denmark, Iceland, Latvia, Belgium, France, Switzerland, and Australia, while survival in the U.S. ranged from 60-69 percent. Survival was under 50 percent in Argentina, Brazil, Chile, Ecuador, Martinique, China, India, Thailand, Bulgaria, Romania, and Russia.
As with myeloid malignancies, five-year survival rates for lymphoid malignancies generally increased over the 15 years of the CONCORD program: Survival rose by 5 percent to 10 percent in 23 countries (37%) and by more than 10 percent in 14 countries (23%).
Pediatric Cancers: Acute Lymphocytic Leukemia (ALL) and Lymphoma
For ALL, the study included 87,351 children from 254 registries in 61 countries. Global survival rates ranged widely, from 50 percent to more than 90 percent.
“… International variation in survival for childhood lymphoma was less marked than for childhood ALL.”
—Claudia Allemani, PhD
Among children diagnosed between 2010 and 2014, five-year age-standardized survival was highest (≥90%) in Puerto Rico, Canada, the U.S., Denmark, Finland, the U.K., Portugal, Belgium, Germany, the Netherlands, Switzerland, Australia, and New Zealand.
Five-year survival was less than 70 percent in Brazil, Chile, Columbia, and Peru, “even after adjustment for the very high background mortality in childhood” in these areas, the researchers noted. Survival was less than 60 percent in China, Ecuador, and Mexico.
Between 1995 to 1999 and 2010 to 2014, five-year survival increased by 10 percent or more in 14 countries (23%).
For lymphoma, the study included 41,196 children from 257 registries in 62 countries. Five-year age-standardized survival most commonly ranged from 80-95 percent. Between 2010 and 2014, five-year survival was at least 90 percent in 29 countries (47%), including the U.S.
Five-year survival trends were generally flat over the 15 years between 2000 and 2014; however, survival increased by 5 percent to 10 percent in the U.S., Korea, Singapore, Taiwan, the U.K., Lithuania, Portugal, Spain, Slovakia, and Germany. Slovenia and Russia experienced the greatest increases in five-year survival (≥20%), while Brazil, Bulgaria, Croatia, and Poland saw increases of at least 10 percent.
“International variation in survival for childhood lymphoma was less marked than for childhood ALL,” the researchers noted. Though they added that “the marked increase in five-year survival among children diagnosed with lymphoma in Brazil (from 69.2% in 2000-2004 to 88.2% in 2010-2014) is likely to reflect a real improvement in diagnosis and treatment.”
“It is crucial for national and regional governments to recognize that population-based cancer registries are key policy tools, both to monitor the impact of cancer prevention strategies and to evaluate the effectiveness of the health system for all patients diagnosed with cancer,” the authors concluded.
The study is limited by its reliance on registry data, which may be missing information and may include discrepancies between the countries reporting information. This can affect the comparability of survival estimates.
The authors report no financial conflicts.
Allemani C, Matsuda T, Di Carlo V, et al. Global surveillance of trends in cancer survival 2000–14 (CONCORD-3): analysis of individual records for 37 513 025 patients diagnosed with one of 18 cancers from 322 population-based registries in 71 countries. Lancet. 2018 January 30. [Epub ahead of print]