Dr Annette McWilliams
Annette McWilliams is hoping her Canadian Cancer Society grant will help prove that an electronic nose can sniff out lung cancer in its early stages.
As a respirologist, Dr McWilliams sees far too many patients with advanced lung cancer. “Lung cancer kills more people than any other cancer. And the reason is that 80% of cases are diagnosed at an advanced stage. It’s not very often that you can offer curative treatment to your patients. I find that disheartening.”
The complexity of the lungs makes early detection difficult. A small tumour can easily hide in the intricate web of bronchial tubes and alveoli. But perhaps cancer cells can be detected in another way: through our breath.
That’s where the electronic nose comes in. This small hand-held device – “it looks like the old cell phones we used back in the early 90s” – collects breath samples and looks for compounds called volatile organic compounds. These are emitted by cancer cells and the surrounding tissues and then released through the breath. “We don’t know the exact pathways,” says Dr McWilliams. “It’s a novel approach, and there’s a lot of interest in it worldwide.”
With colleagues at the BC Cancer Agency in Vancouver, Dr McWilliams has already studied more sophisticated technologies – including autofluorescence bronchoscopy and chest CT scans – as potential early detection tools for lung cancer. “By combining the two techniques, we can find lung cancers at a very small size. In high-risk people 80% of the cancers we diagnose are early-stage and potentially curable.”
But the high-tech tools are expensive and time-consuming. A bronchoscopy requires sedation while a CT scan involves a dose of radiation. It simply isn’t feasible or affordable to screen all smokers and former smokers using these techniques.
We need to develop less invasive and cheaper tests to help us target those people truly at risk. Then we could use our more expensive, invasive investigations on that group.
In her new study, Dr McWilliams will ask 800 smokers and former smokers to breathe into the electronic nose. “It’s very easy and non-invasive – it takes 5 minutes”. Half the group will have an early lung cancer and half will not, based on screening using autofluorescence bronchoscopy and CT scans.
The question is: can the nose detect a difference in the 2 groups? If so, it could become part of a battery of tests routinely given to people at risk for lung cancer.
“Our ultimate goal is to develop a cost-effective screening program that will change this disease in the world. Because if lung cancer can be detected early, it can be cured.”
Great progress has been made
Some cancers, such as thyroid and testicular, have survival rates of over 90%. Other cancers, such as pancreatic, brain and esophageal, continue to have very low survival rates.