Global cancer cases are expected to increase sharply over the coming decades, with annual diagnoses projected to rise from about 20.6 million in 2024 to 35 million by 2050, according to a new report from the World Health Organization. The United Nations health agency warned that unequal access to cancer prevention, detection and treatment is driving a growing divide in cancer outcomes worldwide.
The WHO report, published Wednesday, said advances in cancer surveillance and treatment have improved outcomes in some areas but cautioned that progress has not been shared equally. Lower-income countries are expected to experience a disproportionate share of future cancer cases and deaths because of limited access to health care services and cancer control programs.
“Far too many people are still being left behind,” André Ilbawi, the lead for cancer control at WHO, said at a news conference about the study.
Cancer rates have increased globally in recent years, and the WHO said one in five people will develop cancer during their lifetime. Researchers said the causes behind the rising number of cases are complex, involving changes in cancer rates among different age groups, improved detection methods and longer life expectancy, which increases the likelihood of developing cancers associated with aging.
In some countries, progress in treatment has contributed to better outcomes. In the United States, the rate of new cancer cases has generally remained stable in recent years, while cancer death rates have declined, according to the National Institutes of Health.
Emil Lou, an oncologist and associate professor of medicine at the University of Minnesota, said improvements in treatments such as immunotherapy have significantly increased survival for some patients with advanced cancers, including lung cancer. Lou, who was not involved in the WHO study, said that advances in cancer treatment have occurred alongside a continued global increase in cancer prevalence.
The WHO report emphasized major differences in cancer survival rates between wealthier and poorer regions. Researchers pointed to breast and cervical cancer as examples of how access to health care affects outcomes.
In higher-income countries in Europe and North America, cervical cancer rates have declined significantly, while in many countries in sub-Saharan Africa, cervical cancer remains the leading cancer among women, according to Isabelle Soerjomataram, an epidemiologist with the International Agency for Research on Cancer.
The WHO reported that the five-year net survival rate for breast cancer exceeds 85 percent in high-income countries but falls below 30 percent in low-income countries. The report said countries at all income levels are not investing sufficiently in cancer prevention and treatment programs.
The report also identified areas where progress has been made. Global tobacco use has declined by 27 percent since 2010, and 85 percent of countries now include human papillomavirus vaccines in national vaccination programs. The WHO estimated that 31 percent of girls have received their first dose of the vaccine, compared with 17 percent in 2019.
However, researchers highlighted rising obesity rates as a major concern. Obesity has been linked to more than a dozen cancers, including liver, pancreatic and colorectal cancer, according to the National Institutes of Health.
“It will be a significant added burden for every country globally when cancers associated with obesity become the norm,” Ilbawi said. He added that this trend could affect a significant number of countries within the next two to three decades.
Despite the projected increase in cancer cases, Soerjomataram said many future cases are linked to known risk factors that can be addressed. “Four in 10 new cancer cases are linked to risk factors … we already know how to address,” she said.
