What percentage of cancers are attributable to infections?

Infection-Attributable Cancer Burden

Approximately 12-16% of all cancers globally are attributable to infectious agents, with the most recent high-quality data from 2026 estimating 12% (2.3 million cases annually). 1

Global Burden and Geographic Variation

The proportion of infection-related cancers varies dramatically by region and development status:

• Developed countries: 5-7% of cancers 2, 3
• Developing countries: 23-33% of cancers 2, 3
• Sub-Saharan Africa: Exceeds 25-50% in some countries 1, 2
• Asia: Exceeds 25% in parts of the region 1

This geographic disparity reflects differences in infection prevalence, access to vaccination, screening programs, and treatment infrastructure.

Primary Causative Agents

The five major infectious agents responsible for the vast majority of infection-attributable cancers are:

1. Helicobacter pylori: ~850,000 cases annually (gastric cancer) 1
2. Human papillomavirus (HPV): ~730,000 cases annually (cervical, oropharyngeal, and other anogenital cancers) 1
3. Hepatitis B virus (HBV): ~380,000-420,000 cases annually (hepatocellular carcinoma) 1, 2
4. Epstein-Barr virus (EBV): ~240,000 cases annually (nasopharyngeal carcinoma, lymphomas) 1
5. Hepatitis C virus (HCV): ~160,000-170,000 cases annually (hepatocellular carcinoma) 1, 2

Additional carcinogenic agents include HIV, HTLV-1, KSHV, MCPyV, and parasites like Clonorchis sinensis, Opisthorchis viverrini, and Schistosoma haematobium 4.

Temporal Trends

The burden of infection-attributable cancers is declining over time, particularly in countries with robust public health interventions. For example, in South Korea, the population-attributable fraction decreased from 13.18% (2015) to a projected 8.99% (2030) 5. This decline reflects successful implementation of:

• HBV vaccination programs
• HPV vaccination
• H. pylori eradication treatments
• Improved blood screening practices
• Antiviral therapies for hepatitis C

Age and Sex Distribution

• Age: Approximately 30% of infection-attributable cancers occur in people younger than 50 years 3
• Sex differences:
  • In women, cervical cancer accounts for ~50% of infection-related cancer burden
  • In men, liver and gastric cancers account for >80% of infection-related burden 3
• Males experience higher rates of virus-positive tumors overall 6

Clinical Implications

The substantial proportion of infection-attributable cancers represents a major preventable disease burden. Existing interventions—including prophylactic vaccines (HPV, HBV), screening and treatment programs (HCV, HIV, H. pylori), and detection of precancerous lesions—can significantly reduce cancer incidence when properly implemented 1.

The genomic landscape of virus-positive cancers differs from virus-negative counterparts, with lower somatic mutation burden, distinct mutation signatures, and potentially higher response rates to PD-(L)1 inhibitors 6. This has implications for both prognosis and therapeutic decision-making.