Evidence of Benefit
Prevention of gastric cancer via eradication of H. pylori infection is being actively considered in several countries.[9,10,11,12,13] Many questions remain unanswered concerning the natural history of H. pylori infection; the mechanism of transmission and the rates of reinfection or recrudescence for different populations are unknown.[14,15] Since about half of the world population is infected, antibacterial treatment seems impractical. Vaccination against H. pylori is very effective in experimental animals, but thus far, such efficacy has not been studied in humans. Prevention randomized trials are also under way and might soon indicate whether curing H. pylori infection reduces cancer rates or stops the progression of precancerous lesions.
A meta-analysis of seven studies mostly done in Asia suggests that treatment of H. pylori may reduce gastric cancer risk (from 1.7% to 1.1%), decreasing RR to 0.65 (95% CI, 0.43-0.98). Only two studies assessed gastric cancer incidence, and only two were double-blinded studies. It is unclear how generalizable the results may be to the North American population. It would be useful to know which subgroups of persons with H. pylori are particularly likely to develop cancer, to decide which subgroups might be appropriate to consider for targeted screening and eradication.
A systematic review and meta-analysis showed a 60% increase in gastric cancer in male smokers and a 20% increase in gastric cancer in female smokers compared to nonsmokers. A systematic review of studies addressing the relationship between cigarette smoking and gastric cancer to estimate the magnitude of the association for different levels of exposure to cancer and provides solid evidence to classify smoking as the most important behavioral risk factor for gastric cancer.[17,18,19]
- Stomach. In: World Cancer Research Fund., American Institute for Cancer Research.: Food, Nutrition and the Prevention of Cancer: A Global Perspective. Washington, DC: The Institute, 1997, pp 148-175.
- Buiatti E, Palli D, Decarli A, et al.: A case-control study of gastric cancer and diet in Italy: II. Association with nutrients. Int J Cancer 45 (5): 896-901, 1990.
- Blot WJ, Li JY, Taylor PR, et al.: Nutrition intervention trials in Linxian, China: supplementation with specific vitamin/mineral combinations, cancer incidence, and disease-specific mortality in the general population. J Natl Cancer Inst 85 (18): 1483-92, 1993.
- Plummer M, Vivas J, Lopez G, et al.: Chemoprevention of precancerous gastric lesions with antioxidant vitamin supplementation: a randomized trial in a high-risk population. J Natl Cancer Inst 99 (2): 137-46, 2007.
- Taylor PR: Prevention of gastric cancer: a miss. J Natl Cancer Inst 99 (2): 101-3, 2007.
- Malila N, Taylor PR, Virtanen MJ, et al.: Effects of alpha-tocopherol and beta-carotene supplementation on gastric cancer incidence in male smokers (ATBC Study, Finland). Cancer Causes Control 13 (7): 617-23, 2002.
- Correa P, Fontham ET, Bravo JC, et al.: Chemoprevention of gastric dysplasia: randomized trial of antioxidant supplements and anti-helicobacter pylori therapy. J Natl Cancer Inst 92 (23): 1881-8, 2000.
- Wong BC, Lam SK, Wong WM, et al.: Helicobacter pylori eradication to prevent gastric cancer in a high-risk region of China: a randomized controlled trial. JAMA 291 (2): 187-94, 2004.
- Nomura A, Stemmermann GN, Chyou PH, et al.: Helicobacter pylori infection and gastric carcinoma among Japanese Americans in Hawaii. N Engl J Med 325 (16): 1132-6, 1991.
- Parsonnet J, Friedman GD, Vandersteen DP, et al.: Helicobacter pylori infection and the risk of gastric carcinoma. N Engl J Med 325 (16): 1127-31, 1991.
- Forman D, Newell DG, Fullerton F, et al.: Association between infection with Helicobacter pylori and risk of gastric cancer: evidence from a prospective investigation. BMJ 302 (6788): 1302-5, 1991.
- Parsonnet J, Harris RA, Hack HM, et al.: Modelling cost-effectiveness of Helicobacter pylori screening to prevent gastric cancer: a mandate for clinical trials. Lancet 348 (9021): 150-4, 1996.
- Miehlke S, Kirsch C, Dragosics B, et al.: Helicobacter pylori and gastric cancer:current status of the Austrain Czech German gastric cancer prevention trial (PRISMA Study). World J Gastroenterol 7 (2): 243-7, 2001.
- Cheung TK, Xia HH, Wong BC: Helicobacter pylori eradication for gastric cancer prevention. J Gastroenterol 42 (Suppl 17): 10-5, 2007.
- de Vries AC, Haringsma J, Kuipers EJ: The detection, surveillance and treatment of premalignant gastric lesions related to Helicobacter pylori infection. Helicobacter 12 (1): 1-15, 2007.
- Fuccio L, Zagari RM, Eusebi LH, et al.: Meta-analysis: can Helicobacter pylori eradication treatment reduce the risk for gastric cancer? Ann Intern Med 151 (2): 121-8, 2009.
- Ladeiras-Lopes R, Pereira AK, Nogueira A, et al.: Smoking and gastric cancer: systematic review and meta-analysis of cohort studies. Cancer Causes Control 19 (7): 689-701, 2008.
- González CA, Pera G, Agudo A, et al.: Smoking and the risk of gastric cancer in the European Prospective Investigation Into Cancer and Nutrition (EPIC). Int J Cancer 107 (4): 629-34, 2003.
- La Torre G, Chiaradia G, Gianfagna F, et al.: Smoking status and gastric cancer risk: an updated meta-analysis of case-control studies published in the past ten years. Tumori 95 (1): 13-22, 2009 Jan-Feb.