Osteoporosis drugs may heighten esophageal cancer risk

Findings of a new study have established a link between consumption of bisphosphonates, a commonly used class of osteoporosis drugs, 

and development of esophagus, the cancer [abnormal cells that divide without control, which can invade nearby tissues or spread through the bloodstream and lymphatic system to other parts of the body. ]  of the gullet.

The study researchers aver that the findings are worrisome since this class of osteoporosis drugs are routinely prescribed to old people for strengthening feeble bones.

Merck & Co's Fosamax, Roche's Boniva, and Novartis's Reclast are all bisphosphonates prescribed to prevent bone fractures and make up for bone weakness linked with menopause and osteoporosis. 

Need to evaluate risks and benefits

However, the results should not prompt doctors or patients to instantaneously stop prescribing or taking bisphosphonates, claim the scientists.

"We have to be concerned, but this is the first large study with long-term follow up that has found this effect, and it is just one observational study," lead author of the study, Jane Green of Oxford University's Cancer Epidemiology Unit, said.

"Also, because esophageal cancer [abnormal cells that divide without control, which can invade nearby tissues or spread through the bloodstream and lymphatic system to other parts of the body. ] is uncommon, even a doubled risk is still a low risk," noted Green.

"It's important to see our findings as part of a wider picture. These are very commonly prescribed drugs and we don't have enough information about the long-term risks and benefits," Green added.

The study

For the purpose of the study, Green and her colleagues examined 3000 cases taken from the UK General Practice Research database on men and women aged over 40.

The participants in the study had one of the following cancers diagnosed between 1995 and 2005: esophageal, stomach, or colorectal.

The study established that people with 10 or more prescriptions
for bisphosphonates, or with prescriptions over about five years, were twice more susceptible to contracting esophageal cancer vis-à-vis their counterparts who had no bisphosphonate prescriptions.

"In Europe and North America, the incidence of esophageal cancer at age 60-79 is typically 1 per 1,000 population over five years, and this is estimated to increase to about 2 per 1,000 with five years' use of oral bisphosphonates," declared the study authors.

The study found no relation between bisphosphonate prescriptions and stomach or bowel cancer.

The National Osteoporosis Society said of the findings, "It is a case of balancing the reduced risk of fractures against the side effects of treatment.”

"When you consider the fact that there are 230,000 osteoporotic fractures every year in the UK and 1,150 hip-fracture-related deaths every month, the case for treatment is strong," stated the society.

The findings of the study have been published in the British Medical Journal.

Via : themedguru.com

Osteoporosis drug 'doubles cancer risk'

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 chance of developing oesophageal cancer is about one in 1,000 over five years.

But researchers found that among those who had taken oral bisphosphonates for five years or more the rate doubled to two in 1,000 over the same period.

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) online.

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.

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 Spence described the study as "very telling".

While he said oral bisphosphonates were commonly used to prevent fractures in people who might be at risk of osteoporosis, he thought that approach "isn't supported by the evidence".

He was unconvinced the benefits outweighed the risks, he added.

If the cancer link proved correct, he said "this would be an opportunity to reflect and think about the use of this medication, particularly in people who havenot had a history of fracture."

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".

She said: "what is lacking is reliable information on the benefits and risks of their use in the long-term."

But she added: "Oesophageal cancer is uncommon. The increased risks we found were in people who used oral bisphosphonates for about five years, and even if our results are confirmed, few people taking bisphosphonates are likely to develop oesophageal cancer as a result of taking these drugs."

Their study contradicts one published only a few weeks ago, using the same dataset, that showed no link between the drugs and the disease.

However, the latest research followed patients for almost twice as long and had greater statistical power.

A spokesman for the MHRA said: "On the basis of the findings of this study there is no need for patients to stop taking their bisphosphonate medicine.

"However, in order to reduce the risk of oesophageal irritation, which is a recognised risk associated with bisphosphonate use it is important to carefully follow the instructions in the Patient Information Leaflet.

"Patients should also report any signs of oesophageal irritation such as difficulties or pain on swallowing, chest pain, or heartburn to their doctor."

He added: "The safety of all bisphosphonates will continue to be closely monitored."

Dr Laura Bell, science information officer at Cancer Research UK, said: "This is an important study that will help doctors understand more about the risks and benefits of oral bisphosphonates but it's important to stress that even if people take oral bisphosphonates for a long time the risk of developing oesophageal cancer is still small.

"Anyone who is taking these drugs and is worried about their risk of cancer should talk to their doctor."

A spokesman for the National Osteoporosis Society said: "When you consider the fact that there are 230,000 osteoporotic fractures every year in the UK and 1,150 hip-fracture-related deaths every month, the case for treatment is strong.

"In addition, the researchers point out that the risk is small and that few people taking bisphosphonates are likely to develop oesophageal cancer."

Via : telegraph.co.uk