The virus that causes colds and stomach upsets can be injected into the bloodstream to shrink tumours, scientists in the UK have discovered.
Researchers from the University of Leeds and the UK Institute of Cancer Research say the so-called "reovirus" works by killing the cancer cells while simultaneously developing an anti-cancer immune response.
When it is injected into the bloodstream, it "piggybacks" on red blood cells to reach tumours and avoids detection by the body's immune system.
Past research found the virus could be injected into tumours, which is a more difficult process that requires technical expertise from medical practitioners. By being injected straight into the bloodstream like chemotherapy, the researchers hope it will work with many forms of cancer.
Ten patients with advanced bowel cancer took part in the trial. They were all due to have surgery on tumours that had spread to the liver. In the weeks leading up to surgery, they were given five doses of the viral therapy.
Four weeks after the surgery, tests showed the virus was active in the tumour but not in the healthy sections of the liver, which suggests it is able to specifically target the cancer after being injected into the bloodstream.
''Viral treatments like reovirus are showing real promise in patient trials," said Dr Kevin Harrington, from the Institute of Cancer Research in London who led the study.
''This study gives us the very good news that it should be possible to deliver these treatments with a simple injection into the bloodstream.
"It would have been a significant barrier to their widespread use if they could only have been injected into the tumour, but the finding that they can hitch a ride on blood cells will potentially make them relevant to a broad range of cancers."
The treatment appears to have fewer side effects than chemotherapy.
''We also confirmed that reovirus was specifically targeting cancer cells and leaving normal cells alone, which we hope should mean fewer side effects for patients,'' Dr Harrington said.
The study was published in the journal Science Translational Medicine.