Oral ingestion of bisphosphonates may double the patient’s risk of developing cancer of the esophagus, a UK report released Friday said of the popular osteoporosis drug.

Bisphosphonates are a type of medication often prescribed by doctors for patients at risk of osteoporosis.

An analysis of medical records, which was undertaken by the Medicines and Healthcare products Regulatory Agency and academics at Oxford University’s Cancer Epidemiology Unit found that taking the drug orally for more than five years doubled the risk of developing cancer of the esophagus.

Despite the findings, the Medicines and Healthcare products Regulatory Agency, which regulates medicine in the UK, has said that patients on the drug should not be unduly concerned.

In the UK, around 8000 people are diagnosed with cancer of the gullet each year and only 500 survive, while one million people in the UK are on bisphosphonates to treat osteoporosis, which effects around 3 million people in the country.

The study, which was published in the renowned British Medical Journal (BMJ) will likely prompt a thorough review of how the medicine is prescribed and in what quantities.