Cancer survivorship improving globally—but major disparities still exist

Cancer survival rates are increasing worldwide, but considerable gaps still exist between nations, especially when it comes to more lethal and childhood cancers, data from the CONCORD-3 study states.

The U.S. remains a global leader when it comes to cancer survivorship, Claudia Allemani, PhD, and colleagues wrote in The Lancet, alongside Canada and other developed nations like New Zealand, Finland, Iceland and Norway. Still, underdeveloped countries are struggling to keep cancer rates at bay, and cancer incidence across the world continues to rise.

“Prevention is crucial, but implementation has been slow and incomplete, even in high-income countries,” Allemani and co-authors wrote. “Prevention is a long-term strategy, and not all cancers can be prevented.”

CONCORD-2, this study’s predecessor, established the importance of monitoring global cancer survival for evaluating the effectiveness of health systems and informing global policy when it was released in 2015, the authors said. The trial spanned 67 countries, 10 common cancers, more than a decade of records and 25.7 million patients.

This year, when CONCORD-3 results were published at the end of January, researchers had expanded their criteria to include 18 cancers that collectively represent 75 percent of all types diagnosed worldwide.

“It contributes to the evidence base for global policy on cancer control,” Allemani et al. wrote. “Governments must recognize population-based cancer registries as key policy tools that can be used to evaluate both the impact of cancer prevention strategies and the effectiveness of health systems for all patients diagnosed with cancer.”

CONCORD-3 looked at individual data for 37.5 million cancer patients diagnosed in the 15-year period between 2000 and 2014. Data were provided by 322 population-based cancer registries, according to the study, which came from 71 countries and territories—47 of which provided 100 percent population coverage.

The CONCORD team expanded their research to cover cancers including esophageal, stomach, colon, rectum, liver, pancreas, lung, breast, cervix, ovary, prostate and melanoma cancers. Brain tumors, leukemias and lymphomas were also assessed in both children and adults.

General trends showed a global upward climb, Allemani and colleagues found, including boosts of up to 5 percent in some areas for more lethal cancers like liver, pancreas and lung cancers. Breast cancer survival in Australia is now 89.5 percent. In the U.S., it’s more than 90 percent.

Still, disparities exist between regions, the authors wrote. While breast cancer survivorship is up in countries like Australia and the U.S., India’s survival rate reached 66.1 percent. Just shy of half of all patients diagnosed with melanoma of the skin in China survive the disease, and those rates remain low in the country for lymphoid malignancies and myeloid malignancies, as well.

Gastrointestinal cancers with the highest five-year survival rates were observed in southeast Asia, where stomach cancer survival is 68.9 percent in South Korea, esophageal cancer survival is 36 percent in Japan and liver cancer survival is 27.9 percent in Taiwan.

Children saw the greatest geographic divide—while survival rates of acute lymphoblastic leukemia were 49.8 percent in Ecuador during the study period, they reached 95.2 percent in Finland. Five-year survival from brain tumors, though higher in children than in adults, varied from 28.9 percent in Brazil to nearly 80 percent in Sweden and Denmark.

“In the era of universal health coverage imperatives, the stark inequalities in outcomes shown by CONCORD-3 illuminate the core problems at the heart of global cancer control: from insufficient funding and governance failures through to deficits in workforces fundamental to cancer treatment, such as surgery and radiotherapy,” Richard Sullivan, MD, PhD, wrote in a Lancet editorial accompanying the study. “High-income countries spend substantial amounts on cancer control and research, yet the resources dedicated to enhancing capability and capacity in partner low-to-middle-income countries remain poor.”

In addition, Sullivan wrote, wealthy nations aren’t pouring enough into building effective cancer control systems in countries with fewer resources. Though it’s a two-way street, he said, and lower-income countries need to allocate the proper funds to public health programs, oncoplutocracy—the idea that cancer progress benefits only wealthy countries and their patients—“needs to stop.”

Sullivan said that to develop the type of cancer intelligence systems the world needs, leaders need to pay attention to transnational studies like CONCORD-3.

“National and regional governments must 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,” he wrote.