By 2050, nearly a third of people who develop one of 17 types of cancer will die undiagnosed, according to a new study led by Harvard T.H. Chan School of Public Health.
The study was published April 27 in The Lancet Oncology. Its corresponding author was Zachary Ward, assistant professor of health decision science in the Department of Health Policy and Management and core faculty in the Center for Health Decision Science. Timothy Rebbeck, Vincent L. Gregory, Jr. Professor of Cancer Prevention and director of the Zhu Family Center for Global Cancer Prevention, was also a co-author.
Global cancer incidence is increasing, and missed diagnoses, especially in low- and middle-income countries with weak health systems, are a known problem. Just how big a problem, however, remains unclear. To address this black box, the researchers developed the Global Cancer Workforce microsimulation model, in which they input variables around demographic trends and health system factors—including the availability of ten types of workers involved in cancer diagnosis—to estimate diagnosed and undiagnosed cancer cases across 200 countries between 1990 and 2050. They included 17 types of cancer in the model: mouth, nasopharynx, esophagus, stomach, colon, rectum, anus, liver, pancreas, lung, skin melanoma, breast, cervix uteri, ovary, prostate, bladder, and brain and central nervous system.
The model projected that cancer incidence would rise from 13.58 million cases around the world in 2025 to 19.32 million in 2050—most commonly lung, prostate, and breast. Every continent would see an increase in cancer cases, but to different degrees: Africa was projected to have a lower cancer rate given its younger population, while the inverse was true of Europe, North America, and Oceania. Geographical disparities were also seen in the estimated proportion of undiagnosed cancer cases: In western Africa, the model projected that 67.4% of people with cancer would die undiagnosed by 2050, versus 0.9% in western Europe. Across all countries, an average of 31.5% of people with cancer would die undiagnosed.
According to the researchers, the model not only quantifies the growing global cancer crisis; it also can be used to test potential solutions. “Accounting for demographic and epidemiological trends as well as health system factors, our modeling framework enables evaluation of targeted interventions to strengthen the cancer workforce and improve diagnostic pathways across diverse geographical and socioeconomic settings,” they wrote.
They also used the model to conduct two additional studies published in The Lancet Oncology, projecting global cancer survival and mortality and how scaling up the global workforce related to cancer diagnosis and care could impact mortality.
Read an Earth.com article about the study:
Cancer is rising worldwide, but millions of cases may go undiagnosed
