PPI’s and Risk of Stomach Cancer

Australian statistics reveal the risk to age 75y of being diagnosed with stomach cancer is 1 in 172 or 0.6% which is 6 cases in 1000 people, with a risk to age 75y of dying from stomach cancer 1 in 397 or 0.25%

In Australia, over 47,700 people die annually from cancer however stomach cancer remains an uncommon, accounting for 1078 deaths/year.

Out of 123,000 new cases of cancer are diagnosed annually in Australia, only 1.8% or 2294 are due to stomach cancer.

This is approximately 7.3 new cases of stomach cancer per 100,000 people per year, causing 3.2 deaths per 100,000 people per year.

Although this recent study revealed a 2 times (possibly up to 4 times) increased risk of stomach cancer with long-term use, this only applied to Hong Kong patients who had undergone Helicobacter antibiotic eradication therapy. Of course, as significant as the increased risk is, we should also bear in mind that the overall risk factor is still low. This equates to about 4 additional cases of stomach cancer per 10,000 people per year, which is worth keeping in perspective. 

The recent Hong Kong data conflicts with several previous studies indicate no increased risk of stomach or other GI cancers with long term PPI use.

A 2016 study for USA showed 61 684 persons were followed up for a total of 547 020 person-years found no evidence that PPIs conferred an excess risk of gastric cancer, other gastrointestinal cancers.

The Hong Kong study has a “geographic bias” and partly focused on H pylori infection and its relationship with gastric cancer.

In terms of study weaknesses, the researchers  lacked information on some risk factors, such as diet, family history, and socioeconomic status.  And despite the large sample of more than 63,000 H pylori–infected patients, the small number of gastric cancer cases did not allow for any “meaningful evaluation of the dosage effect and role of different PPIs,” the researchers say. The team also notes that PPIs users may have a higher chance of undergoing endoscopy than non-PPI users, leading to discovery of more gastric cancers due to surveillance bias.

However, where possible, unnecessary long-term PPI use should be avoided.

Keep in mind, the major risk factors for stomach cancer are: