Strategies 5-12: Screening, Vaccines, and Specific Exposures
Strategy 5 — Limit alcohol: alcohol is a Group 1 carcinogen (definitive cause of human cancer) for cancers of the mouth, pharynx, larynx, esophagus, liver, colorectum, and breast. There is no evidence of a safe threshold for cancer risk — even moderate drinking (1 drink/day) elevates breast cancer risk by approximately 7-10%. The mechanism involves acetaldehyde (a DNA-reactive carcinogen produced by alcohol metabolism), oxidative stress, estrogen elevation, folate depletion, and enhanced carcinogen absorption through alcohol-damaged gut mucosa. The World Cancer Research Fund’s recommendation is simply “to not drink alcohol” for cancer prevention — though acknowledging that light drinking is a personal choice with relatively modest absolute risk at low doses.
Strategy 6 — Protect against sun exposure: UV radiation causes >90% of melanomas and the vast majority of basal cell and squamous cell carcinomas — the most common cancers in fair-skinned populations. Broad-spectrum SPF 30+ sunscreen applied generously and regularly reduces squamous cell carcinoma risk by 40% and melanoma risk by approximately 50% in randomized trials. Additional measures: avoid tanning beds (UV-A exposure significantly exceeds natural sunlight; tanning bed use before age 35 increases melanoma risk by 59%), wear sun-protective clothing for extended outdoor exposure, and check skin for suspicious lesions annually (the ABCDE rule: Asymmetry, Border irregularity, Color variation, Diameter >6mm, Evolution/changing).
Strategy 7 — Get vaccinated (HPV and HBV): human papillomavirus (HPV) causes virtually all cervical cancers, 90% of anal cancers, 60-70% of oropharyngeal cancers, and significant proportions of vaginal, vulvar, and penile cancers. The HPV vaccine (Gardasil 9) prevents infection with the 9 most carcinogenic HPV strains and is recommended for all people through age 26 (and available through age 45). Girls vaccinated before HPV exposure have virtually eliminated their risk of HPV-associated cervical cancer in population-level data from the UK, Australia, and Scandinavia. Hepatitis B vaccination prevents HBV infection, which causes approximately 50% of hepatocellular carcinoma (liver cancer) cases globally.
Strategy 8 — Cancer screening: colorectal cancer is one of the most preventable cancers because it develops slowly through identifiable precancerous polyps, providing a multi-year window for intervention. Colonoscopy can both detect and remove polyps, preventing their malignant transformation. Annual fecal immunochemical testing (FIT) or Cologuard DNA stool testing, or colonoscopy every 10 years, starting at age 45 (earlier for high-risk individuals), reduces colorectal cancer mortality by 30-40%. Annual low-dose CT scanning for current or former heavy smokers (55-80 years, 30+ pack-year history) reduces lung cancer mortality by 20-24% in the National Lung Screening Trial.
Strategies 9-12: (9) Limit red and processed meat — processed meat (bacon, sausage, hot dogs, deli meat) is a Group 1 carcinogen for colorectal cancer; limit to <2 servings weekly. Red meat is Group 2A (probable carcinogen); limit to <500g cooked weekly. (10) Reduce radon exposure — radon gas (from uranium decay in soil, entering through building foundations) is the second leading cause of lung cancer after smoking; test home radon levels and remediate if above 4 pCi/L. (11) Avoid occupational carcinogen exposure — asbestos, benzene, formaldehyde, vinyl chloride, and chromium exposure are regulated occupational carcinogens; ensure appropriate protective equipment and ventilation in exposed occupations. (12) Regular low-dose aspirin — meta-analyses show 30-40% reduction in colorectal cancer risk and possible reductions in several other cancers with low-dose (81-100mg) aspirin in people over 50; discuss benefit-risk balance with physician given bleeding risks.