The United States Food and Drug Administration wants research carried out on the osteoporosis drug Fosamax and other similar drugs to check potential links to oesophageal cancer.
Diane Wysowski of the administration's division of drug risk assessment said researchers should check into potential links between so-called bisphosphonate drugs and cancer.
She said in a letter in Thursday's New England Journal of Medicine that since the initial marketing of Fosamax in 1995, the FDA has received 23 reports in which patients developed oesophageal tumours.
Typically, two years lapsed between the start of the drug and the development of oesophageal cancer. Eight patients died, she reported. The drug is known generically as alendronate.
In Europe and Japan, 21 cases involving Fosamax, manufactured by Merck, have been logged, as well as six instances where Procter & Gamble's Actonel or risedronate and Didronel or etidronate, and Roche's Boniva or ibandronate may have been involved. Six of those people died.
Oesophagitis, which is an inflammation of the lining of the tube carrying food to the stomach, is already known to be a side effect of the drugs, which is why patients are instructed to remain upright for at least a half hour after taking them.
In addition, Ms Wysowski said, doctors should avoid prescribing the drugs to people with Barrett's oesophagus, which is a change in the lining that leads to the stomach.
It is often found in people with acid reflux disease and itself increases the risk of cancer.
The drugs aim to treat bone-weakening osteoporosis by increasing bone mass.
