By Stephen Adams
A drug taken by more than a million people with osteoporosis could double their risk of developing cancer of the oesophagus, according to a study published today.
Those who have taken oral bisphosphonates for five years or more are twice as likely to develop the cancer than those who have not, the analysis of medical records found.
Every year almost 8,000 people in Britain are diagnosed with cancer of the oesophagus, or gullet cancer, and about 7,500 people die from it.
Survival rates are low compared to other cancers, with only three in 10 surviving more than a year after diagnosis.
Among the general population of people aged 60 to 79, the incidence of oesophageal cancer is about one in 1,000.
But researchers found that among those who had taken oral bisphosphonates for five years or more the rate doubled to two in 1,000.
Among men it increased from 1.5 to three per 1,000 and among women from 0.5 to to one per 1,000.
Last night the Medicines and Healthcare products Regulatory Agency (MHRA), the Government’s medicine’s regulator, said there was “no need” for patients to stop taking the medication on the basis of the study alone.
The MHRA collaborated with academics at Oxford University’s Cancer Epidemiology Unit to look at data from the UK General Practice Research Database, which has anonymised patient records for around six million people.
Among those aged 40 and over, 2,954 had oesophageal cancer, 2,018 had gastric cancer and 10,641 had bowel cancer, all diagnosed between 1995 and 2005.
The results also showed that the chance of oesophageal cancer was 30 per cent higher in people with one or more previous prescriptions for oral bisphosphonates, compared to people who had never taken the drugs.
The risk was almost double for those who had 10 or more prescriptions compared with those who had had between one and nine, according to the study, published today in the British Medical Journal (BMJ).
There were no links between the drugs and stomach or bowel cancer.
Some three million people suffer from osteoporosis, according to the National Osteoporosis Society. The Duchess of Cornwall, whose mother and grandmother both died of the disease, is president of the charity.
More than a million people were prescribed a bisphosphonate in 2009/10, according to the MHRA, which work by preventing bone loss and rebuilding lost bone. More than 6.5 million prescriptions were issued.
They are a group of drug that include alendronate, etidronate and risedronate, also marketed under the brand names Fosamax, Didronel and Actonel.
Doctors often prescribe them as a preventative measure for those who might be at a higher risk of osteoporosis, such as post-menopausal women.
However, some doctors are becoming concerned that they are being over-prescribed with scant thought of their side effects, which are known to include difficulty swallowing, chest pain and heartburn.
Dr Des Spence, a Glasgow GP who has also written on the subject in the BMJ, said doctors should focus less on the drugs and more on how to avoid falls, as well as on improving diet and increasing targeted exercise.
Dr Jane Green, lead author of the study, said their results were “part of a wider picture” because bisphosphonates were “increasingly prescribed to prevent fractures”.