Medical and engineering researchers at McGill University and Polytechnique Montréal developed a technique using a handheld probe that enables surgeons to find elusive cancer cells in the brain. The team led by McGill’s Kevin Petrecca and Polytechnique Montréal’s Frederic Leblond reported their findings yesterday in the journal Science Translational Medicine (paid subscription required).
The McGill-Polytechnique team in Montreal, Canada aimed to provide cancer surgeons with a more robust tool for revealing brain cancer tissue in patients with glioma, a type of cancer affecting glial cells that surround and support the brain’s nerve cells. Cancers of this type can be aggressive and highly malignant, and account for about one-third of all brain cancers, including the kind contracted by the late Ted Kennedy, U.S. senator from Massachusetts.
A particular difficulty faced by brain cancer surgeons is detecting residual cancer cells in the brain that are largely indistinguishable from healthy tissue, which often lead to the cancer returning or spreading following surgery. Currently there are no technologies available to physicians that detect residual cancer cells in the brain.
To address this problem, Petrecca, Leblond, and colleagues harnessed Raman spectroscopy, an analytical imaging technology that measures molecular vibrations by the amount of light scattered from a laser directed to a specimen or sample. Raman spectroscopy can also be used with little or no sample preparation, thus making it feasible for real-time surgical applications.
The researchers adapted a Raman spectroscopy probe made by EmVision LLC, a Florida company developing these devices for research and diagnostics. Their technique holds the probe in contact with the brain, which illuminates a small spot about one millimeter into the tissue. That illumination returns Raman light scattering measures in real time, indicating the absence or presence of cancerous tissue.
The team tested the technique with 17 brain cancer patients at Montreal Neurological Institute and Hospital with moderate to high-grade gliomas. The tests showed the probe was able to distinguish between normal and cancerous brain tissue with a sensitivity and specificity of 91 percent or better. In addition, the device revealed previously undetectable brain cancer cells scattered among healthy brain cells.
Petrecca, Leblond, and colleagues now plan a clinical trial to test the device on larger samples of patients. The following video features the senior researchers telling more about the probe.