The largest and most up-to-date study of international cancer registries shows that survival trends are generally increasing, even for some lethal cancers.
The largest and most up-to-date study of international cancer registries shows that survival trends are generally increasing, even for some of the more lethal cancers, such as liver and lung.
The CONCORD-3 study analyzed individual patient records from 322 cancer registries in 71 countries and territories to compare 5-year survival from diagnosis for more than 37.5 million adults and children with one of 18 common cancers. These cancers represent three-quarters of all cancers diagnosed worldwide every year between 2000 and 2014. The researchers published their results in the Lancet.
“Continuous monitoring of global trends in cancer survival is crucial to assess the overall effectiveness of health systems worldwide, and to help policy-makers plan better strategies for cancer control. But, inadequate or unreliable data prevent governments from understanding the true nature and magnitude of the public health problems created by the growing cancer burden. This leaves governments poorly equipped to develop national cancer plans that will translate into real improvements in survival for patients,” said lead author Claudia Allemani, PhD, of the Cancer Survival Group at the London School of Hygiene & Tropical Medicine.
For most cancers, 5-year net survival remains the highest in the world in the United States, Canada, Australia, New Zealand, Finland, Iceland, Norway, and Sweden. In some countries, survival has increased by up to 5% for cancers of the liver, pancreas, and lung, which are some of the more lethal cancers.
Survival for most cancers remains highest in a handful of countries. For women diagnosed with breast cancer in the United States and Australia, the 5-year survival rate is 90% compared with 66% for women diagnosed in India. Within Europe, the 5-year breast cancer survival rate increased to 85% or more in 16 countries, as compared with a low of 71% in Russia.
For gastrointestinal cancers, the highest levels of 5-year survival are seen in Southeast Asia. This could be due to long-standing population-based endoscopic screening programs. By contrast, in the same region, survival is generally lower than elsewhere for melanoma of the skin and for both lymphoid and myeloid malignancies.
Not all major cancers have seen large improvements. Even in 2014, pancreatic cancer remained highly lethal in all countries, with 5-year survival typically less than 15%.
A wide gulf in survival exists for childhood cancers. Five-year survival rates for acute lymphoblastic leukemia ranged from higher than 90% in Canada, the United States, and nine European countries to below 60% in China, Mexico, and Ecuador. For brain tumors, 5-year survival rates in children are higher than for adults, but range widely globally, from 28.9% in Brazil to nearly 80% in Sweden and Denmark.
The researchers noted that cancer registries should be given adequate resources to register all patients and to link the registry data to up-to-date death records. “Governments must recognize cancer registries as efficient public health instruments that produce a continuous stream of valuable information on both the impact of cancer prevention strategies and the effectiveness of health systems, and at very low cost,” they concluded.