The new technique enables scientists to spot changes in the nucleus of cells in the earliest stages of cancer.

More than 85% of all cancers originate in the epithelium that lines the internal surfaces of organs throughout the body.

At this stage the cancer is relatively easy to treat - but almost impossible to detect using current methods.

A team from the Massachusetts Institute of Technology has overcome this problem by developing an optical probe which uses a technique known as light-scattering spectroscopy to detect pre-cancerous and early cancerous changes in the epithelia cells.

The new technique relies on the fact that cell nuclei change in the early stages of cancer and the differences scatter light in a characteristic way.

Until now the changes were only detectable after a biopsy - a tissue sample - was taken.

The researchers tested their new technique in four different organs during routine endoscopic cancer screening.

The tip of the optical probe was brought into contact with the tissue to be tested using an endoscope.

The scattering of light was recorded without the need for any tissue to be removed.

Writing in the journal Nature, they say: "Our results show that light-scattering spectroscopy has the potential to detect pre-cancerous lesions and pre-invasive cancers throughout the body.

"This technique should significantly improve the efficiency of cancer screening and surveillance."

The research is published in the journal Nature.