Cannabis Destroys Tumours In Brain, Claim Scientists

By David Derbyshire Daily Telegraph - March 8, 2000 - CHEMICALS found in cannabis can destroy life-threatening brain tumours, a new study says this week. Scientists have found that the main active ingredient in marijuana halts the growth of malignant gliomas - deadly cancerous growths in the brain. The discovery will add to the growing calls from patients and doctors to legalise cannabis for medical use. In the past few years, scientists have rediscovered the medicinal properties of cannabis. Studies have shown that substances in the plant can ease the symptoms of multiple sclerosis, prevent nausea and offset side-effects of cancer chemotherapy. Now cannabis could also be used as an anti-cancer drug, says a team from Complutense University in Madrid, reporting in the journal Nature Medicine. Researchers induced tumours in the brains of 45 rats. A third were given THC, the main active chemical in cannabis, a third were given a synthetic cannabinoid, while the rest were used as controls. Within 18 days the untreated rats died but, when THC and the man-made cannabinoid were injected directly in the tumours over seven days, they had a dramatic effect. The chemicals destroyed the tumours in a third of the mice and prolonged the life of another third by up to six weeks. "These results may provide the basis for a new therapeutic approach for the treatment of malignant gliomas," the team, led by Dr Manuel Guzman, report. Dr Daniele Piomelli, pharmacologist at the University of California in Irvine, said the discovery could have important implications for tumour treatment. He said: "Although incomplete, these findings must be seriously considered as glial tumours are peculiarly resistant to traditional therapy." Spanish researchers believe that cannabinoids trigger the build-up of a chemical messenger, ceramide, which in turn leads to programmed cell death in the tumour. The chemicals were selective, only triggering cell death in cancerous brain cells. Future studies will try to find out why the cannabinoids appear to have no effect on healthy brains and whether they can be used on people. Gliomas are extremely difficult to treat. Even after a course of surgery, radiation and chemotherapy, the median survival rate is less than a year. In Britain, there are 1,800 new cases a year. In some American states, doctors can encourage the use of cannabis legally to relieve nausea in cancer treatments, prevent weight loss in Aids patients, ease spinal injury pain and slow the advance of the eye disease glaucoma. Last year, American researchers showed that another chemical in cannabis called anandamide could be used to treat Parkinson's disease and schizophrenia. The British Medical Association supports the use of cannabinoids in drugs research but is against the legalisation of cannabis for medicine. Cannabis plants contain more than 400 active ingredients, many of which have unpredictable side-effects.