Breath of hope for early detection
Each year about 1600 Kiwis die from lung cancer, making it the leading cause of cancer-related death in New Zealand.
By comparison, about 600 people die from breast cancer each year and 300 from melanoma.
Waikato Hospital respiratory physician Cat Chang says there is a great need to develop an affordable and non-intrusive method of screening for lung cancer.
Many people in the early stages of lung cancer don’t exhibit any symptoms.
Common symptoms of lung cancer include a cough (often with blood), weight loss, wheezing and chest pain.
‘‘Lung cancer is our biggest cancer killer for the reason that most people present late, when the disease is advanced, and we can’t do as much to treat these people,’’ Chang says.
‘‘To improve treatment for people with lung cancer what we need is early detection.
‘‘With cervical cancer, women can have a smear test, and with breast cancer we have mammograms. But with lung cancer, we don’t have a good screening tool.’’
Ideally, such a tool would be non-invasive, accurate and cheap to perform.
That’s where Tim Edwards and his dogs come in.
Chang says that, throughout the history of medicine, doctors have used breath to help diagnose medical conditions.
‘‘What we hope is these dogs can detect tiny amounts of chemicals in people’s breath that might be associated with lung cancer, and hopefully be able to do this when the cancer is at an early stage.
‘‘And of course, breath is easy to get and it’s non-invasive.’’
To date, about 200 patients attending Waikato Hospital’s respiratory clinic have given breath and saliva samples for Edwards’ research project.
Despite smoking rates in New Zealand declining in recent decades, Chang says this has yet to translate into a drop in lung cancer rates.
At present 16 per cent of
‘‘We don’t have long-term data, but the very short-term data we have on vaping is that it’s not benign.’’
adult New Zealanders smoke. And although smoking is a leading cause of lung cancer, the disease also affects nonsmokers.
The growing popularity of electronic cigarettes also has some health professionals concerned.
‘‘We don’t know the longterm effects of vaping,’’ Chang says. ‘‘The short-term effect from animal studies and biopsies from healthy volunteers that have vaped shows definite cell damage in the lungs, similar to what you get if you were smoking a cigarette.
‘‘We don’t have long-term data, but the very short-term data we have on vaping is that it’s not benign.’’
If Edwards’ study shows dogs can reliably sniff out lung cancer, Chang says there’s no reason the screening tool can’t be applied to other cancers, such as of the prostate.