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pH Probe Enables More Precise Breast Cancer Surgery

Researchers have developed an optical fibre probe that distinguishes the pH in breast cancer tissue from normal tissue – potentially allowing surgeons to be much more precise when removing breast cancer.

Current surgical techniques to remove cancer lack a reliable method to identify the tissue type during surgery, relying on the experience and judgement of the surgeon to decide how much tissue to remove. Because of this, surgeons often remove excessive healthy tissue. Even then, follow-up surgery is required by up to 20% of breast cancer surgery patients when all the cancer is not removed.

The optical fibre probe, described in Cancer Research, uses the principle that cancer tissue has a more acidic environment than normal cells as they produce more lactic acid as a by-product of their aggressive growth.

A pH indicator embedded in the tip of the optical probe emits a different colour of light depending on the acidity. A miniature spectrometer on the other end of the probe analyses the light and therefore the pH.

“How we see it working is the surgeon using the probe to test questionable tissue during surgery,” says project leader Dr Erik Schartner of the ARC Centre of Excellence for Nanoscale BioPhotonics at The University of Adelaide. “If the readout shows the tissues are cancerous, that can immediately be removed. Presently this normally falls to post-operative pathology, which could mean further surgery.”

The researchers currently have a portable demonstration unit and are doing further testing. They hope to progress to clinical studies in the near future.