Global burden of gastric cancer attributable to Helicobacter pylori

We previously estimated that 660,000 cases of cancer in the year 2008 were attributable to the bacterium Helicobacter pylori (H. pylori), corresponding to 5.2% of the 12.7 million total cancer cases that occurred worldwide. In recent years, evidence has accumulated that immunoblot (western blot) is more sensitive for detection of anti-H. pylori antibodies than ELISA, the detection method used in our previous analysis. The purpose of this short report is to update the attributable fraction (AF) estimate for H. pylori after briefly reviewing new evidence, and to reassess the global burden of cancer attributable to H. pylori. We therefore reviewed the literature for studies comparing the risk of developing non-cardia gastric cancer (NCGC) in cases and controls, using both ELISA and multiple antigen immunoblot for detection of H. pylori. The results from prospective studies were combined, and the new pooled estimates were applied to the calculation of the AF for H. pylori in NCGC, then to the burden of infection-related cancers worldwide. Using the immunoblot-based data, the worldwide AF for H. pylori in NCGC increased from 74.7% to 89.0%. This implies approximately 120,000 additional cases of NCGC attributable to H. pylori infection for a total of around 780,000 cases (6.2% instead of 5.2% of all cancers). These updated estimates reinforce the role of H. pylori as a major cause of cancer. What's new? Some 5.2 percent of the estimated 12.7 million new cancer cases in 2008, including 75% of non-cardia gastric cancer cases (NCGC), were attributed to the bacterium Helicobacter pylori. However, those percentages may be an underestimate, given the low sensitivity of detection of anti-H. pylori antibodies. Here, using improved estimates from prospective studies based on immunoblot, the fraction of all cancers and NCGC attributable to H. pylori was found to be 6.2 and 89% percent, respectively. Our findings reinforce the significance of the bacterium as a major cause of cancer.