More Focus on H Pylori and Gastric Cancer Needed

Electron micrograph of H pylori possessing multiple flagella (negative staining); source: Yutaka Tsutsumi, MD, Wikimedia Commons

Though uncertainties remain, gastric cancer and Helicobacter pylori represent an enormous opportunity for prevention. An amazing 770,000 out of 989,000 total gastric cancer cases around the world in 2008 can be attributed to the bacterial infection, suggesting that eradication could yield drastic reductions in incidence.

“Despite its importance, gastric cancer receives little attention from research funding agencies or public health organizations,” wrote authors led by Rolando Herrero, MD, PhD, of the International Agency for Research on Cancer in Lyon, France, and colleagues in JAMA. Estimates suggest 700,000 people will die of gastric cancer this year, making it the third-most common cause of cancer deaths around the world. Herrero and his colleagues note that the National Cancer Institute, for example, spends only 0.2% of its budget (about $12 million) on gastric cancer; the annual cost for treating the disease in the United States is around $2 billion.

The lack of attention is evident from the most basic of observations. A search for gastric cancer studies at ClinicalTrials.gov yields only a quarter of the results for breast cancer, half that of prostate cancer, and about a third that of lung cancer. This is even more remarkable given what has been learned about H pylori and the possibility for gastric cancer prevention; as the JAMA authors point out, only 10% of that $12 million from the NCI goes to prevention research.

Several studies have shown that eradicating the bacteria can reduce gastric cancer risk. In one trial in China, gastric cancer risk dropped from 4.6% to 3% after treatment of H pylori, and another meta-analysis of six randomized trials showed a similar drop from 2.4% to 1.6% with eradication. Still, Herrero and colleagues wrote that even in aggregate these trials don’t give us precise estimations of benefits and harms of intervention, and almost all work has been done in Asian populations making extrapolation difficult. There are also, of course, potential harms to eradication, including a possibly increased risk of esophageal adenocarcinoma.

In spite of the limitations and uncertainties, many think screening and eradication should be implemented widely. A working group from Herrero’s institution published a report on the issue, and suggested that “the large global burden of gastric cancer, and the feasibility of treating its principal cause make this disease a logical target for intervention.”

There are ongoingtrials that may help shed light on the issue in coming years as well, potentially pushing more toward screening and eradication. The JAMA authors suggest, however, that “practical questions about the implementation and outcomes of population-based gastric cancer prevention programs could best be answered by direct observation in the communities where they are applied.” They recommend demonstration programs, and an increased push for research that might identify at-risk sub-populations.

“Ignoring gastric cancer in the hope that it will soon disappear is not a tenable health policy,” they conclude.