Using an optical fiber probe, researchers have developed a more precise technique to distinguish breast cancer tissue from normal tissue. This novel device will potentially give surgeons the upper hand when removing breast cancer and prevent follow-up surgeries, which are currently needed for 15 to 20 percent of breast cancer surgery patients where all the cancer is not removed. Erik Schartner demonstrates an experimental system of the optical fiber probe. Courtesy of the University of Adelaide. Researchers at the University of Adelaide in the ARC Center of Excellence for Nanoscale BioPhotonics (CNBP), the Institute for Photonics and Advanced Sensing, and the Schools of Physical Sciences and Medicine say the optical probe works by detecting different pH levels in the two types of tissue. Erik Schartner, project leader and postdoctoral researcher at the CNBP said "We have designed and tested a fiber-tip pH probe that has very high sensitivity for differentiating between healthy and cancerous tissue with an extremely simple — so far experimental — setup that is fully portable." Current cancer removal surgeries lack a reliable method of identifying the tissue type during surgery, often relying on the judgement of the surgeon to decide how much tissue to remove. This sometimes leads to removal of excessive healthy tissue or of cancerous tissue being left behind. "This is quite traumatic to the patient, and has been shown to have long-term detrimental effects on the patient's outcome," Schartner said. The optical fiber probe uses the principle that cancer tissue has a more acidic environment than normal cells; they produce more lactic acid as a byproduct of their aggressive growth. The pH indicator embedded in the tip of the optical probe emits a different color of light depending on the acidity. A miniature spectrometer on the other end of the probe analyses the light and the pH. "How we see it working is the surgeon using the probe to test questionable tissue during surgery," said Schartner. If the readout shows the tissues are cancerous, they can immediately be removed. The researchers currently have a portable demonstration unit and are doing further testing. They hope to progress to clinical studies in the near future. The study is published in the journal Cancer Research (DOI: 10.1158/0008-5472.CAN-16-1285).