Long-term Proton Pump Inhibitor Use Associated With Stomach Cancer

The prolonged use of proton pump inhibitors following treatment for H. pylori infection of the stomach has been linked to an increased risk of stomach cancer. The study from Hong Kong was published in BMJ Gut. Proton pump inhibitors, which include drugs like omeprazole, lansoprazole and pantoprazole, have been used for several years for the treatment of stomach ulcers. They bring about their effect by blocking a target called the proton pump in the inner lining of the stomach, thereby reducing the acid secretion by the stomach. They are included in the treatment regimen of Helicobacter pylori infection.

Helicobacter pylori or H. pylori is a bacterium that attaches to the inner layer of the stomach. Most patients with H. pylori in their stomachs do not suffer from any symptoms. Some people suffer from gastritis or stomach ulcers and even run a small risk of suffering from stomach cancer. The infection is treated with specific drug regimens that contain a proton pump inhibitor, at least two antibacterials and sometimes an additional drug.

Physicians sometimes advise the long-term use of proton pump inhibitors to reduce gastric acidity after the treatment for H. pylori infection. Scientists gathered data from patients who received treatment for H. pylori infection and were then prescribed either proton pump inhibitors or alternative acid-reducing drugs called H2 blockers over prolonged durations. H2 blockers include drugs like ranitidine, famotidine and nizatidine. The study population included 63,397 adults who were followed up for an average period of 7.5 years. The scientists found that:

Most patients took H2 blockers, while 5% took proton pump inhibitors for an average of around 3 years.

The risk of stomach cancer was more than double in the group taking proton pump inhibitors, while the increased risk was not noted in those taking H2 blockers

The risk increased with:

• A longer duration of use of proton pump inhibitors. The intake of the proton pump inhibitors for more than a year increased the risk 5 times, while an intake for three or more years increased the risk by more than 8 times
• More frequent use of proton pump inhibitors. The risk with the daily use of the proton pump inhibitors was around four times as compared to weekly use.

Since H. pylori was absent in the stomach due to prior treatment, the risk of stomach cancer due to H. pylori was eliminated in the study. The study was, however, not designed to establish whether proton pump inhibitors cause stomach cancer. Further studies designed to specifically answer the question are the need of the hour.

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Reference:

1. Cheung KS, Chan EW, Wong AYS, et al Long-term proton pump inhibitors and risk of gastric cancer development after treatment for Helicobacter pylori: a population-based study Gut. doi: http://dx.doi.org/10.1136/gutjnl-2017-314605

Source-Medindia