“What we’ve now discovered is that lots of diseases and conditions — and cancer included — that they actually have different volatile organic compounds, these smelly compounds, that are associated with them,” Guest tells NPR’s Rachel Martin. “And dogs can smell them.”

The dogs offer an inexpensive, non-invasive method to accompany the existing blood tests for prostate cancer, which detect prostate-specific antigen, or PSA, Guest says.

“It’s a low false-negative but a very high false-positive, meaning that three out of four men that have a raised PSA haven’t got cancer,” she explains. “So the physician has a very difficult decision to make: Which of the four men does he biopsy? What we want to do is provide an additional test — not a test that stands alone but an additional test that runs alongside the current testing, which a physician can use as part of that patient’s picture.”