Researchers in Louisiana have linked GERD with the development of upper aerodigestive tract (UADT) cancers in elderly individuals, but causality remains elusive.
GERD — chronic gastroesophageal reflux — affects approximately 20 percent of Americans, according to the National Institute of Diabetes and Digestive and Kidney Diseases. Researchers have long debated a possible link between GERD and UADT malignancies, with much attention focused on the role of GERD-related chronic inflammation as a potential contributor; chronic inflammation increases risk for cancer elsewhere in the body, according to the National Cancer Institute.
In a case-control study in JAMA Otolaryngology–Head & Neck Surgery, researchers from Tulane University School of Medicine, Louisiana State University Health Sciences Center New Orleans and Ochsner Clinic and Health System used the SEER–Medicare database to compare 13,805 patients age 66 and older who had UADT cancer to an equal number of matched patients who did not have cancer. The presence of GERD was linked with greater odds of malignancy for six UADT sites — larynx, hypopharynx, oropharynx, tonsil, nasopharynx and paranasal sinuses — including a more than threefold risk increase for laryngeal cancer, the largest of any cancer type in the study.
“[T]he closer the site was to the presumed exposure of reflux, which we understand is coming from the stomach, ... the higher the odds of developing cancer,” says study author Edward McCoul, MD, MPH, FACS, Director of Rhinology and Sinus Surgery in the Department of Otorhinolaryngology at Ochsner Clinic and Health System. “So that was strongest for the larynx and for the paranasal sinuses.”
The researchers speculate that inflammation from chronic exposure to GERD prompts cellular changes that lead to cancer, but further study is needed to establish causality, according to Dr. McCoul.
Tantalizing but Uncertain
The findings are intriguing, but other factors could account for the association between GERD and UADT cancers, according to American Gastroenterological Association expert Stuart Spechler, MD, AGAF, Chief of the Division of Gastroenterology and Co-director of the Center for Esophageal Disease at Baylor University Medical Center. Those factors include tobacco and alcohol, which researchers note they were unable to take into account because the database does not report them.
“[The] ideal study would be to follow these patients prospectively and see how many develop cancer, but this isn’t a common cancer, so it would require thousands of patients to be followed for many years, and that would be enormously expensive and time-consuming,” says Dr. Spechler, who was not involved in the research. “So we’re going to be left, unfortunately, with the possibility that GERD might be a risk factor for these tumors, but I don’t think we’re going to have proof absolutely one way or the other anytime in the near future.”
In Search of Causality
Finding chemical markers of GERD in tumor samples may be one way to definitively establish GERD as a cause of upper aerodigestive tract cancers, according to Edward McCoul, MD, MPH, FACS, Director of Rhinology and Sinus Surgery in the Department of Otorhinolaryngology at Ochsner Clinic and Health System. He and other researchers are exploring the possibility of analyzing banked tumor tissue for chemicals found in reflux in order to establish whether patients who underwent surgery for laryngeal cancer had a history of reflux.