The study, published on February 22 in the journal Cancer, shows that as much as 17% of two types of cancer of the esophagus and larynx are associated with gastroesophageal reflux disease (GERD). While GERD is already a known risk factor for esophageal adenocarcinoma, one of the cancers examined in the study, researchers sought to corroborate this finding and learn more about why.
“We found that GERD was associated with an increased risk of esophageal and laryngeal squamous cell carcinomas,” Christian C. Abnet, PhD, MPH, tells Verywell by email. Abnet is the lead investigator in the study and a senior investigator and branch chief of the Metabolic Epidemiology Branch in the Division of Cancer Epidemiology and Genetics at the National Cancer Institute (NCI), part of the National Institutes of Health. “These findings contribute to developing a complete picture of what may contribute to the development of cancer in these organs,” he says.
Why Is GERD Linked to Cancer?
GERD is believed to increase the risk of cancer of the esophagus because the acid that is regurgitated up from the stomach irritates and damages the esophageal lining. This acid can also reach the larynx, where the vocal cords are located, and can cause irritation and hoarseness.
GERD May Double the Risk of Certain Throat Cancers
To investigate the link between GERD and cancers of the esophagus and larynx, Abnet and his colleagues examined a huge amount of information from 490,605 adults who took part in the NIH-AARP Diet and Health Study. This is a large prospective study that mailed questionnaires in 1995 and 1996 to 3.5 million members of AARP, formerly known as the American Association of Retired Persons, who were between the ages of 50 and 71. The study participants were living in California, Florida, Louisiana, New Jersey, North Carolina, or Pennsylvania, or in the metropolitan areas of Atlanta and Detroit. The questionnaires asked them about their health, diet, and lifestyles.
In this study, the factor being investigated is GERD. By looking at diagnosis data from Medicare claims, Abnet and his colleagues estimated that nearly 24% of the people who filled out the questionnaires had a history of GERD, compared to their estimate that about 22% of the general population the same age has the condition.
They then examined the data for incidence of three kinds of cancer of the esophagus or throat: esophageal adenocarcinoma, laryngeal squamous cell carcinoma, and esophageal squamous cell carcinoma. While esophageal adenocarcinoma is the most common type of esophageal cancer in the United states, squamous cancers of the esophagus and larynx are rare, Abnet says. However, globally, esophageal squamous cell carcinoma is much more common than adenocarcinoma, he adds.
The study found that 2,108 participants developed esophageal or laryngeal cancer from 1995 to 2011. Of these, 931 people developed esophageal adenocarcinoma, 876 developed laryngeal squamous cell carcinoma, and 301 developed esophageal squamous cell carcinoma.
The elevated risk was about the same even when other risk factors for these types of cancer, such as sex, smoking status, obesity, and alcohol consumption, were considered.
Abnet and his colleagues concluded that 16.92% of laryngeal squamous cell carcinoma cases and 17.32% of esophageal squamous cell carcinoma cases in the United States may be associated with GERD.
What to Make of the Findings
If these findings are confirmed by further studies of GERD and esophageal and laryngeal cancer, it may guide clinical surveillance of GERD patients in the future, Abnet says.
“All observational studies have limitations and our study alone does not confirm that GERD raises the risk for all these cancers," he says. “We expect that our publication may lead other researchers to test this hypothesis in future studies.”
GERD is one risk factor for esophageal and laryngeal cancer, but not the most serious one. “In the United States, tobacco and heavy alcoholic beverage intake are the primary causes of esophageal and laryngeal squamous cancers, so avoiding those exposures is the most important preventive measure,” Abnet says.
“Our findings should not alarm people diagnosed with GERD,” he adds. “The best course of action for those with GERD symptoms is to speak to their physician about lifestyle modifications or medical interventions that could alleviate their GERD symptoms and improve their quality of life.”
In some cases, physicians may recommend additional specific tests and treatments for GERD, but whether these treatments could also reduce the risk of esophageal and laryngeal cancer remains to be determined, he adds.
