People who soothe their sour stomachs by swallowing over-the-counter antacids regularly for years appear to be at greater risk for a type of esophageal cancer, according to researchers at City of Hope and the Keck School of Medicine of the University of Southern California.
The research team found that risk of esophageal adenocarcinoma was elevated among long-term users of nonprescription acid-reducing drugs who were not under a doctor’s care for an upper-gastrointestinal disorder. The scientists published their findings in the February issue of Cancer Epidemiology, Biomarkers & Prevention.
 Leslie Bernstein (Photo by Walter Urie) |
“These over-the-counter medications suppress symptoms, but do not influence the underlying disease process. It may be that people are using these medications to mask symptoms of precancerous conditions, without going to see a physician, permitting cancer to develop,” said Leslie Bernstein, Ph.D., chief of the Division of Cancer Etiology in the Department of Population Sciences and senior author on the study.
Although esophageal adenocarcinoma is relatively rare, the cancer’s incidence has jumped sixfold in the United States in the last three decades. Scientists suspect gastroesophageal reflux disease, or GERD, brought on by obesity may be to blame.
Some experts have expressed concern that suppressing production of stomach acid through medication may increase risk, too. Many of these medications made the jump from physicians’ prescription pads to readily accessible drugstore aisles in recent years. This study, however, was conducted before certain prescription medications like cimetidine and omeprozole became available over the counter.
To learn more, the research team interviewed more than 900 men and women in Los Angeles County who had been diagnosed with adenocarcinoma in either the esophagus or upper or lower regions of the stomach. They compared them to nearly 1,400 people without esophageal or stomach cancer.
The researchers asked about patients’ lifestyles and habits, including their use of over-the-counter and prescription antacids, as well as whether they had been diagnosed with disorders ranging from ulcers to GERD.
They found that people who took nonprescription acid-neutralizing drugs regularly for more than three years were more than six times as likely to have esophageal adenocarcinoma than were those who never took the drugs. And within this group, those who had no history of physician-diagnosed, upper-gastrointestinal disorders were nearly 11 times as likely as non-drug-users to develop esophageal cancer.
Prescription acid-reducers were not associated with increased risk of esophageal cancer; and antacid use also appeared unrelated to risk of adenocarcinoma of the stomach.
Some have suggested that regular, prolonged use of antacids without any limits on the amounts used may allow alkaline bile to evade neutralization by stomach acid and rise up to the esophagus, chronically damaging tissue and raising cancer risk, Bernstein noted.
However, “people also may simply be self-medicating with antacids to reduce symptoms of undiagnosed disease,” she added. “Antacid use itself might not actually increase risk.”
Further study is needed to better understand how various acid-reducing medications influence risk.
The paper’s lead author was Lei Duan, Ph.D., of City of Hope, and co-authors included Anna H. Wu, Ph.D., of the Keck School, and Jane Sullivan-Halley of City of Hope. Bernstein is a professor emeritus at the Keck School.
The research was supported through grants from the California Tobacco Related Research Program, the National Cancer Institute and the National Institute of Environmental Health Sciences.
