Cannabis chemicals tackle tumours

A substance found in marijuana has been found to attack a rare kind of brain tumour, say experts.

In experiments carried out on rats, the treatment eradicated the malignant glioma in one-third of cases, and another third lived longer than expected.

Malignant gliomas, cancers which usually affect the brain stem, are hard to treat.

Gliomas often develop in childhood, and, depending on the size and type of tumour, may prove difficult to remove.

Although some patients are cured, the usual average survival time from diagnosis is only 40 to 50 weeks.

However, researchers at Complutense University in Spain are hopeful that the cannabis extracts could translate into effective treatments.

They injected these cannabinoid chemicals directly into gliomas which had been implanted into the brains of rats.

However, the study only focused on 30 rats, and was described as "incomplete" by commentators.

One of the researchers said he hoped to start trials on human subjects next year.

Dr Manuel Guzman said: "We are quite happy with the findings and we believe we can at least try to see what happens in humans."

The normal treatment for gliomas is surgery, combined with radiotherapy or chemotherapy, but survival rates are poor.

Chemical chain reaction

The researchers believe that the cannabinoids set off a complex chemical chain reaction in the brain which led to the destruction of the cancer cells.

The cannibis extracts led to an increase of a fat called ceramide, which led to protein reactions and eventually the destruction of the tumour.

Testing programmes are currently underway to check how effective cannabis extracts are against various illnesses.

There is strong anecdotal evidence that it can ease the symptoms of multiple sclerosis and inflammatory illness, as well as post-operative pain.

In addition, some patients choose to smoke cannabis to relieve the nausea associated with chemotherapy.

However, studies have shown that smoking cannabis carries health risks in the same way that smoking tobacco does.

The British Medical Association strongly advises people not to smoke or eat cannabis for medicinal reasons.

A spokesman said: "Doctors are awaiting the results of trials currently being carried out to see if extracts of cannabis are safe and effective.

"We would want to see it produced as a prescription only medicine."

Part of the ongoing research is to identify the "active components" among the hundreds of ingredients of cannabis, and produce a pure version.

In that way, patients would be able to enjoy the benefits without getting "high".