Dogs can smell cancer, now AI is being taught to do it

World Half Full
Mar 8
3 min read

HEALTH

Colleen Ferguson says her two-year-old German shepherd, Inca, saved her life by detecting cancer in its earliest stage. She thought something was wrong when the dog kept obsessively smelling her breath.

For weeks, Inca would sniff at her mouth and frown. Ferguson, 60, got her teeth checked, and doctors did tests related to her gluten intolerance, but all came back negative.

However, Inca wouldn’t stop, so Ferguson booked a full body scan, which revealed a “golfball-sized tumour” in her left lung. It was stage 1 cancer.

“She just had this focused intent on my mouth. She would give me such a look and walk away,” says the former science teacher from Kent in England. “In no way did I expect lung cancer. It was such a shock because I am a non-smoker, and I had absolutely no symptoms at all, apart from being tired.”

After surgery to remove the tumour, Ferguson didn’t require any further treatment or radiation, and she’s now making the most of her retirement years as a creative writer and published author.

“The surgeon told me, ‘we never catch it at stage 1, your dog has saved your life’, she says. “I was just so lucky. To catch it that early was just remarkable. People need to listen to their dogs.”

Researchers in the UK have evidence that proves dogs can, indeed, detect cancer with their superior sense of smell.

The nonprofit Medical Detection Dogs (MDD) began a groundbreaking study in 2024 to teach seven dogs — Labradors, cocker spaniels, and a retriever — how to detect tumours simply by smelling urine in pots.

“Dogs have shown us time and time again that diseases have an odour,” Claire Guest, CEO and Chief Scientific Officer at MDD, told The Times. “We are not sure whether that is the odour of the tumour itself, or the body’s response to the tumour.”

Clinical trials have proven that dogs can reliably detect diseases including prostate cancer, bladder cancer, Covid-19, and even Parkinson’s — and dogs can be trained to do so.

Scientists at Massachusetts Institute of Technology (MIT) are now developing an ‘e-nose’ trained by artificial intelligence to replicate the dogs’ responses to cancer samples. In collaboration with MDD, Dr Andreas Mershin, a quantum physicist at MIT, has created such a machine that uses chemical sensors to make it capable of “smelling” urine samples — and detecting the volatile organic compounds, which are tiny odour molecules in the air.

The e-nose is now being tested on 500 urine samples from patients at the Milton Keynes University Hospital London, including some with prostate cancer to see if it can accurately detect cancer. Working with a chemistry team at the University of Texas at El Paso, Mershin hopes it will be approved as a clinical tool in hospitals within two years.

“This is a major milestone,” says Mershin. “We’ve worked to emulate the dogs’ abilities and train machines in a similar way — rewarding them for correct identifications.”

And such e-nose capabilities could ultimately be added to smartphones. Our devices already have eyes and ears, and now technology with olfactory intelligence is the next frontier — informing a generation of non-invasive diagnostic tools for better health.

“It’s like giving our devices a new sense: a nose. When I trained our first cancer detection dog over 15 years ago, the goal was always to inform scalable technology — not to have a dog in every hospital,” says Guest. “Seeing that vision start to come to life with this e-nose is an incredibly proud moment.”

TOP Colleen and Inca

PHOTO SWNS

BOTTOM The e-nose device in development

PHOTO Medical Detection Dogs