The UK charity, Medical Detection Dogs, is to start the world’s first breast cancer detection trial using the olfactory powers of dogs.
The charity, set up in 2007, has established a worldwide reputation for training dogs to detect prostate, renal and bladder cancer using urine samples, and advises other smaller clinics in Europe, Australia and the US.
Although it has not been determined what the dogs detect, it is thought volatile substances emitted by cancerous cells are present in the urine of cancer patients and give off an odour perceptible to dogs.
The charity’s founder, Claire Guest, who will be principal investigator of the trial, hopes to find volatiles present in breath samples collected from breast cancer patients.
Dr Guest said: “It doesn’t seem necessarily logical that breast cancer should lead to volatile substances being present in breath samples, but we have seen sufficient anecdotal and minor trial evidence to feel confident this is an avenue well worth pursuing. If it works, it will revolutionise the way we think about breast cancer.
“In the long term, we hope to assist scientists to develop e-noses – electronic systems that are able to detect the odour of cancer through cheap, quick, non-invasive tests. If we can prove the principle that breast cancer is detectable on a person’s breath, machines could eventually detect that odour.”
Latest figures from Cancer Research UK show more than 50,000 people are diagnosed with breast cancer each year in the UK and just under 12,000 die.
Dr Guest, who was alerted to her own breast cancer by her dog, added: “Under current procedures for detecting breast cancer, many women have to wait until they are 50 before they are invited in for their first mammogram.
“As someone who has had breast cancer significantly younger than 50, I am painfully aware that would have been too long for me to wait before being scanned for cancer for the first time.
“After 50, women are invited to have another mammogram every three years. This means a woman could have breast cancer for two years without finding out, by which point the tumour could be well established. The problem is, it is not good for women to be scanned more regularly than that because of the exposure to radiation.
“So, if we succeed in proving dogs can detect breast cancer on breath samples, younger women and women such as myself, who have had breast cancer and need regular checks to ensure the tumour has not returned, could simply breathe into a tube and find out safely and quickly their state of health.”
Previous trials carried out by Medical Detection Dogs include a 2004 investigation into the detection of bladder cancer using urine samples, published in the British Medical Journal and a 2011 study into the same type of cancer but with a larger sample size, published in the Journal Cancer Biomarkers.
The charity has also been working with renal and prostate samples. With prostate cancer it has achieved 93% reliability, compared to the 75% false positive rate of the traditional PSA tests.