Cannabis extracts can help slow the growth of cancerous tumours when used alongside radiotherapy treatments, new research has suggested.

Two active chemical components found in cannabis plants, tetrahydrocannabinol (THC) and cannabidiol (CBD) were tested as part of research into the treatment of brain cancer tumours.

This type of cancer is notoriously difficult to treat and has a particularly poor prognosis. The rate of survival for patients five years after diagnosis is just 10 per cent.

A team at St George's, the University of London, treated brain tumours in mice in a variety of ways, either without any treatment, the cannabinoids alone, irradiation alone or with the cannabinoids and irradiation at the same time.

They found tumours growing in the brains of mice were drastically slowed down when the THC and CBD cannabinoids were combined with irradiation.

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The team are now discussing testing the treatment in human clinical trials.

Dr Wai Liu, Senior Research Fellow and lead researcher on the project, described the results as “extremely exciting”.

"Those treated with both irradiation and the cannabinoids saw the most beneficial results and a drastic reduction in size," he said.

“In some cases, the tumours effectively disappeared in the animals. This augurs well for further research in humans in the future. - this is a mostly fatal disease at the moment.

"The benefits of the cannabis plant elements were known before but the drastic reduction of brain cancers if used with irradiation is something new and may well prove promising for patients who are in gravely serious situations with such cancers in the future."