GERD-related cancer risk is higher with smoking, lower with NSAIDs

NEW YORK (Reuters Health) - Non-steroidal anti-inflammatory drug (NSAID) use and smoking each modify the effects of acid reflux, but in different ways, new research shows.

In a study of patients with gastroesophageal reflux disease (GERD), the risk of esophageal or gastroesophageal junction malignancy was higher in smokers but lower in regular users of NSAIDs.

This is not the first time that senior investigator Dr. David Whiteman of the Queensland Institute of Medical Research in Brisbane, Australia, and his colleagues have analyzed the effect of lifestyle factors on GERD-related cancer risks. Previously they reported that obesity and gastroesophageal reflux had synergistic effects on the risk of esophageal adenocarcinoma.

In a paper in the January issue of Gut, they describe a study in which they collected health and demographic data from 365 patients with esophageal adenocarcinoma, 426 with gastroesophageal junction adenocarcinoma, 303 with esophageal squamous cell carcinoma, and 1,580 controls.

Not surprisingly, subjects who had GERD symptoms at least weekly had higher cancer risks than controls, with odds ratios of 6.4 for esophageal adenocarcinoma, 4.6 for gastroesophageal junction adenocarcinoma, and 2.2 for esophageal squamous cell carcinoma. (An association of reflux symptoms with esophageal squamous cell carcinoma has not been shown before, the researchers point out.)

When risk estimates were adjusted for combined exposure to acid reflux and smoking, however, heavy smokers (30 or more pack-years) with weekly GERD symptoms had odds ratios of 12.3 for esophageal adenocarcinoma, 13.5 for gastroesophageal junction adenocarcinoma, and 9.2 for esophageal squamous cell carcinoma, compared to controls. For never-smokers, the corresponding odds ratios were 6.8, 4.3, and 1.8, respectively.

However, when patients with at least weekly reflux symptoms took NSAIDs at least once a week, they had odds ratios of 4.8 for esophageal adenocarcinoma, 3.1 for gastroesophageal junction adenocarcinoma, and 1.0 for esophageal squamous cell carcinoma, compared to controls. In contrast, patients with frequent reflux who did not use NSAIDs had odds ratios of 13.9 for esophageal adenocarcinoma, 8.5 for gastroesophageal junction adenocarcinoma, and 2.8 for esophageal squamous cell carcinoma.

Of note, in patients with frequent GERD, the use of acid suppressants had no effect on cancer risks.

Smoking may increase esophageal cancer risk by promoting inflammation and lowering the tone of the esophageal sphincter, the researchers note.

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