Infection-Attributable Cancers

Primary Infectious Agents and Associated Cancers

• The American College of Physicians and other medical organizations acknowledge that Helicobacter pylori is the leading infectious cause of cancer worldwide, responsible for approximately 810,000 cases annually, with a mechanism involving progression from chronic active gastritis to invasive gastric carcinoma 1, 2
• The American Gastroenterological Association recommends that all infected individuals with H. pylori develop gastritis and remain at risk for gastric cancer throughout their lifetime, highlighting the importance of early detection and treatment 1
• Organized screening and eradication programs for H. pylori in high-risk populations, such as those implemented in the Matsu Islands, have been shown to reduce gastric cancer incidence by 53% and cancer-related deaths by 25%, according to the American Cancer Society 1, 2
• The Centers for Disease Control and Prevention (CDC) notes that HPV-16 and HPV-18 are detected in 72% of invasive anal cancers and are responsible for 86-97% of all anal cancers, with high-risk populations including men who have sex with men (MSM) with HIV 3
• The National Comprehensive Cancer Network recommends that men who have sex with men (MSM) with HIV have a significantly higher risk of anal cancer, with an incidence rate of 131 per 100,000 person-years, compared to men with HIV (40-60 per 100,000 person-years) and women with HIV (20-30 per 100,000 person-years) 3, 4
• People living with HIV (PLWH) have a 15- to 35-fold increased risk of anal cancer compared to the general population, according to the Journal of the National Comprehensive Cancer Network 3

Clinical Implications for Cancer Prevention

• The American College of Preventive Medicine suggests that widespread application of existing public health interventions, such as vaccination programs (HPV, hepatitis B), safer injection practices, and antimicrobial eradication treatments (H. pylori), could substantially reduce the global cancer burden 1, 2
• Organized screening programs for H. pylori in high-risk populations are cost-effective, particularly when targeting young adults before irreversible molecular damage occurs, as recommended by the American Gastroenterological Association 1, 2

Important Caveats

• The National Comprehensive Cancer Network notes that while infections are important causes of morbidity and mortality in cancer patients, the relationship is bidirectional, with the malignancy itself and cancer treatments predisposing patients to severe or recurrent infections 5, 6