One in eight new cancer cases worldwide in 2024 were linked to infections, according to a study published by the International Agency for Research on Cancer (IARC). The findings, released in The Lancet Oncology, highlight five infections responsible for the majority of these cases, with low- and middle-income countries bearing the greatest burden.
The study estimated that 2.3 million of the 19.2 million new cancer cases reported in 2024 were infection-related. The five primary pathogens identified were:
- Helicobacter pylori (H. pylori), a stomach bacterium linked to bowel cancer and spread through contaminated food and water;
- Human papillomavirus (HPV), associated with cervical, anal, and other cancers;
- Hepatitis B and C viruses, major contributors to liver cancer;
- Epstein-Barr virus (EBV), linked to several cancers including lymphoma.
Geographic disparities were pronounced, with Eastern Asia accounting for 990,000 infection-related cancer cases—42% of the global total—primarily driven by H. pylori and hepatitis B. Western Europe reported 24,000 HPV-linked cancer cases, making HPV the region’s leading infection-related cause of cancer.
Preventable Measures Highlighted
Researchers emphasized that many of these infections—and thus their associated cancers—are preventable through existing interventions. Key strategies include:
- Vaccination: HPV and hepatitis B vaccines were singled out as critical tools.
- Public health measures: Improving food and water safety to reduce H. pylori transmission, promoting safe injection practices, and expanding access to HIV prevention drugs (PrEP) and condoms.
- Early detection: Screening for cervical and anal cancers in high-risk populations.
The study’s authors noted that cost-effective prevention strategies are underused, particularly in low-resource settings, due to financial, political, and societal barriers. They called for greater investment in infection control to reduce the global cancer burden.
Expert Perspectives on Scope and Impact
Experts reviewing the study offered varying assessments of its findings. Dr. Patrick Moore, chair in Innovative Cancer Research at the University of Pittsburgh, described the 12% estimate as conservative, suggesting the true proportion of infection-linked cancers could be higher. He pointed to geographic variations, noting that cutbacks in HIV treatment funding in sub-Saharan Africa could lead to increased infectious cancers, while expanded neonatal hepatitis B vaccination in Asia may reduce liver cancer rates.
Karl Munger, a professor at Tufts University, argued that the IARC’s estimate was lower than expected, citing prior analyses suggesting infection-associated cancers account for 15–20% of global cases. He emphasized that infections are an underappreciated cause of cancer, particularly in regions with limited healthcare infrastructure.
Long-Term Implications and Policy Gaps
The study underscores the global inequities in cancer prevention, with 77% of infection-related cases occurring in low- and middle-income countries. Researchers warned that without targeted interventions, these disparities will persist, exacerbating the cancer burden in vulnerable populations.
The findings also raise questions about vaccine access and public health infrastructure. While vaccines for HPV and hepatitis B exist, uptake remains uneven, with Western Europe and high-income countries showing higher vaccination rates compared to regions where infections are most prevalent.
The IARC’s report serves as a call to action for policymakers, urging sustained investment in vaccination programs, sanitation improvements, and early cancer detection to curb the spread of infection-related malignancies.