Scientists double brain cancer survival time

Capsules of drugs may be implanted into the brain

Scientists have used tiny biodegradable capsules containing cancer drugs to fight a hard-to-treat brain tumour which normally kills within a year.

Between 13 and 22% of all patients diagnosed with brain cancers have malignant growths called glioblastomas, which, although it can be cut out by surgeons, usually quickly regrows in the same place despite radiotherapy given after the operation.

In a small study, French researchers implanted dissolving capsules called "microspheres" around the tumour site following surgery.

They contain a standard chemotherapy drug routinely given to cancer patients.

However, survival time was doubled, and the scientists say the capsules could offer a new, effective way of treating brain tumours.

Dr Philippe Menei of the Centre Hospitalo-Universitaire d'Angers said: "We believe that the biodegradeable microsphere implants may provide a more exact way to direct time-released doses of chemotherapy drugs to the area of the brain that is most vulnerable to further tumour growth."

Surgery is the most common treatment of brain tumours

Usually, patients with malignant glioblastomas treated with surgery and radiation treatment live on average just under a year.

But the four patients given the capsules in addition lived on average 98 weeks, and two are still cancer-free three years after surgery.

Dr Menei said: "Due to their size, the microspheres used in this study can be implanted easily in discreet, precise and functional areas of the brain without damaging the surrounding tissue."

Blood-brain barrier

The main problem facing cancer specialists trying to deliver chemotherapy to brain tumours is the "blood-brain barrier", a natural defence system of the body designed to protect the sensitive brain from damage caused by any chemical in the bloodstream.

In many cases, it prevents powerful treatments reaching the brain tumour in sufficient concentrations to kill all the cells involved.

The high doses which would have to be given to patients to do this often rule out chemotherapy as an option.

The number of brain tumours diagnosed in the UK is increasing, although no-one knows why. About four in ten of these turn out to be benign, although even these can still pose a danger to health.

Following surgery, most patients need extensive rehabilitation to recover.