Oral bisphosphonates, including Fosamax, may increase risks for esophageal cancer if they are used for longer than 5 years. In September 2010, a study published in the British Medical Journal found that people who had taken the oral bisphosphonates over five years had twice the risk of developing esophageal cancer.
Fosamax and similar drugs are approved to treat bone disorders, including osteoporosis in post-menopausal women, and Paget’s disease. Other oral bisphosphonates of this type include the drugs Actonel, Boniva, Didronel and Skelid.
According to the 2010 study, case reports have suggested an association between use of oral bisphosphonates for osteoporosis and increased risk of esophageal cancer. But the evidence is limited, and no adequately large study on the issue had been published. The British Medical Journal study analyzed data from the UK General Practice Research Database, which has anonymised patient records for around six million people. The researchers focused on men and women 40 years old, 2,954 of whom had esophageal cancer. Another 2,018 had stomach cancer, while 10,641 had colorectal (bowel) cancer. All of the subjects were diagnosed between 1995 and 2005. Each case was compared with five controls matched for age, sex, general practice and observation period.
The study found that people with 10 or more prescriptions for oral bisphosphonates, or with prescriptions over about five years, had nearly double the risk of esophageal cancer compared with people with no bisphosphonate prescriptions. No increased risk was seen with colorectal or stomach cancer.
Based on their findings, the authors estimated that with five years’ use of oral bisphosphonates this would increase to two cases of esophageal cancer per 1000 people taking bisphosphonates over five years. Typically, esophageal cancer develops in one per 1000 people at age 60-79 over five years.
A year after the British Medical Journal study was published, the U.S. Food drug Administration (FDA) issued a Drug Safety Communication to update the public on its ongoing review of the possible association between oral bisphosphonate drugs and an increased risk of cancer of the esophagus (esophageal cancer). The agency noted that studies on the issue have been conflicting, and it was unable to reach a conclusion. While the FDA said it believed the benefits of bisphosphonates continued to outweigh their risks, it acknowledged that further study of the issue was needed. Its safety review is ongoing.