The Cancer Research UK funded trial, called FRAGMATIC, is investigating whether a drug called Dalteparin can treat this problem and whether the drug may also improve the survival of lung cancer patients.

Stoke Mandeville Hospital currently has four patients taking part in the trial under the principal investigator, Dr Nick Bates.

The hospital hopes to recruit at least another 12 patients this year.

People with lung cancer are at an increased risk of blood clots in their veins because of chemotherapy, surgery, inactivity or the lung cancer itself.

Clots can be dangerous and even fatal if they dislodge and travel to the lungs. They can also cause pain in the chest and breathlessness.

Dalteparin, also known as Fragmin, may also have an anticancer effect and lead to an improvement in quality of life and survival rates after the lung cancer diagnosis because it is thought that the blood thinning drug may affect how cancer cells spread through the blood stream, but this is not known for sure.

This trial is designed to help answer these questions and to identify any possible side effects of using the drug in this situation.

The trial, which was created by Dr Fergus Macbeth and Dr Simon Noble at Velindre Hospital in Cardiff, is hoping to recruit 2,400 patients and is due to involve between 50 and 100 centres around the UK.

Dr Bates, who is leading the trial at Stoke Mandeville, said: "Blood clots are quite common in people who have lung cancer and may be dangerous.

"With this research, we hope to learn how to reduce the risk of this problem and improve the treatment for patients.

"We are working hard to find better and more effective ways to treat this difficult illness."

Kate Law, Cancer Research UK's clinical trials director, said: "Lung cancer remains the second most common cancer in the UK.

"It is vital we continue to research new treatments and also improve existing treatments for the disease.

"Clinical trials like FRAGMATIC are important in helping to do this and developing better treatments for patients."

For more information on the trial, please visit the www.cancerhelp.org.uk or call Raj Jheeta, Cancer Research Nurse, on 01296 315908.