Saliva tests may provide a new way of diagnosing mouth cancers, new research has shown.

Scientists found that it was possible to measure DNA shed by head and neck tumours in both saliva and blood.

Lead researcher Nishant Agrawal, from Johns Hopkins University School of Medicine in the US, said: “In our study, testing saliva seemed to be the best way to detect cancers in the oral cavity, and blood tests appeared to find more cancers in the larynx, hypopharynx and oropharynx. However, combining blood and saliva tests may offer the best chance of finding cancer in any of those regions.”

For the study 93 patients with newly-diagnosed and recurrent head and neck cancers were asked to provide saliva samples and 47 also gave blood samples.

Tumour DNA was detected in the saliva of 76 per cent of patients and in the blood of 87 per cent.

All 46 types of oral cavity, or mouth and tongue, cancers were correctly identified through the saliva tests.

Blood tests identified tumour DNA in 91 per cent of oropharynx cancers, 86 per cent of larynx cancers and all three hypopharynx cancers.

The oropharynx and hypopharynx are located at the back of the throat. The larynx is another name for the voice box.

Co-author Bert Vogelstein, from the Johns Hopkins Kimmel Cancer Center, said: “Our ultimate goal is to develop better screening tests to find head and neck cancers among the general population and improve how we monitor patients with cancer for recurrence of their disease.”

The research is reported in the journal Science Translational Medicine.