A recent study published in The Lancet Oncology reveals that approximately 1 in 8 cancer cases worldwide can be attributed to infections that are either treatable or preventable. The research, conducted by the International Agency for Research on Cancer, analyzed data from the Global Cancer Observatory's Cancer Today database to estimate the incidence of cancer globally in 2024. The study found that 2.3 million new cancer cases, equivalent to 12% of all cancer diagnoses, were attributable to infections.
The study identified two infections as major contributors to cancer cases: Helicobacter pylori (H. pylori) and human papillomavirus (HPV). H. pylori was primarily associated with gastric cancers, while HPV was predominantly linked to cervical cancer. Together, these two infections accounted for over 1.5 million cancer cases in 2024. Other infections, such as Hepatitis B, Epstein-Barr virus, and Hepatitis C, also contributed substantially to cancer cases.
According to Gary Clifford, senior author of the study and epidemiologist at the International Agency for Research on Cancer, prevention efforts can make a significant difference in reducing cancer risk. Clifford emphasized that many of these infections can be prevented through vaccines, screening, or relatively straightforward treatments. He stressed the importance of awareness and implementation of prevention programs.
The study also highlighted the uneven distribution of infection-related cancer burden worldwide. Low-income and middle-income countries accounted for 77% of all infection-attributable cancer cases, reflecting differences in the prevalence of cancer-causing infections and access to vaccines, screening, and treatment. Veronika Fedirko, professor of epidemiology at The University of Texas MD Anderson Cancer Center, noted that even within the United States, there are disparities in cancer incidence related to infections.
Harriet Rumgay, epidemiologist at the International Agency for Research on Cancer, noted that highly effective prevention measures already exist for four of the five leading infectious causes of cancer, as well as for HIV. These measures include vaccines for HPV and hepatitis B, as well as testing and treatments for H. pylori and hepatitis C. Rumgay emphasized that prevention works, but it requires awareness, politics, finances, and public buy-in.
The study built on earlier research published in 2018, incorporating 16 additional infection-cancer pairs, including some cancers paired with the Epstein-Barr virus (EBV). Clifford explained that EBV was one of the first cancer-causing agents of infection to be discovered, and since then, it has been identified in other cancers, particularly nasopharyngeal carcinomas.
Experts agree that having a cancer-causing infection does not mean that a person will develop cancer. These infections increase the risk of certain cancers, but most people who are infected will never develop cancer. Prevention efforts, including vaccination, testing, and treatment, can significantly reduce the risk of cancer. Clifford emphasized that getting tested and following up with a doctor can almost eliminate cancer risk.
Key points
- 2.3 million new cancer cases globally in 2024 were attributable to infections.
- Low-income and middle-income countries accounted for 77% of all infection-attributable cancer cases.
- Highly effective prevention measures exist for four of the five leading infectious causes of cancer.
