NEW YORK (Reuters Health) - Taking drugs that block the secretion of gastric acid does not appear to increase the risk of developing colorectal cancer, according to a new report.

The drugs in question are known as proton pump inhibitors (PPIs), often prescribed for people with gastric acid reflux. Prilosec and Nexium are familiar examples. There has been some speculation that reducing stomach acid could allow bacterial overgrowth, leading to toxic bile formation, which might increase the risk of developing colorectal cancer.

"Our study did not show an association between PPI use and colorectal cancer," Dr. Eva M. van Soest from Erasmus University Medical Center, Rotterdam, the Netherlands told Reuters Health. "Careful monitoring seems wise, and studies should be repeated when longer follow-up is available."

In a study conducted between 1996 and 2005, van Soest's team investigated the association between the use of PPIs and the risk of colorectal cancer in 457,024 subjects.

The odds of developing colorectal cancer did not increase among patients who had ever used PPIs compared with those who had not, the researchers report in the American Journal of Gastroenterology. Neither the duration of PPI use nor the dosage had any effect.

"Although every study including ours has some weaknesses," van Soest added, "two other recently published studies did not find an increased risk of colorectal cancer with PPI use either."

Nonetheless, the investigators say, further studies are needed to see if there's any risk with long-term use of proton pump inhibitors.

SOURCE: American Journal of Gastroenterology, April 2008.

• More News on Colorectal Cancer
• More News on GERD

Related MedlinePlus Pages:

• Colorectal Cancer
• GERD