CT scans can identify suspect lumps in the lungs, but they can’t determine which of these lumps are likely to be cancerous, and those that are non-cancerous which should just be monitored.
Researchers at Boston University School of Medicine (BUSM) in the US have now discovered that looking at certain genes within nose cells could help make a decision on which lumps to investigate further.
In the US long-term smokers, who are at high-risk of lung cancer, are offered CT scans to screen for the disease. But at the moment a biopsy is needed to differentiate between non-cancerous nodules and lung cancers, so scientists are looking to develop non-invasive ways to aid diagnosis. If confirmed in larger studies the findings of the latest study could spare some US patients who have been given a CT scan from a costly and potentially risky surgical biopsy.
Lung cancer screening is not available in the UK. A large European trial, the NELSON trial, may help clarify the benefits and harms of lung screening when its findings are published, and the UK National Screening Committee has said that it will review its policy based on these results.
Dr Avrum Spira, lead researcher on the US study from BUSM, said there is a “clear and growing need” to develop diagnostic tests that can help distinguish those who need invasive tests and those who should be monitored instead.
The research, which is published in the Journal of the National Cancer Institute, is based on previous work by Spira’s team which found that a genetic ‘signature’ in lung cells, caused by long-term tobacco smoking, could potentially tell apart patients with lung cancer and those with a benign nodule in their lungs.
As long-term tobacco smoking similarly alters genes in the nose, the team looked if sampling cells from this area could offer the same information without the need for invasive lung sampling.
The team looked at more than 550 nasal samples from current or former long-term tobacco smokers with suspected lung cancer, identified by CT scans that showed suspicious nodules. The researchers found that they could detect lung cancer-associated genetic changes in both nose and lung cell samples, and that these could help predict the risk that the patient had lung cancer.
The team concluded that sampling nose cells could be a non-invasive way to aid the detection of lung cancer in high-risk patients.
Professor Samuel Janes, a Cancer Research UK expert on lung cancer, said: “This interesting study is based on the idea that cigarette smoke damages the whole airway, including the mouth and nose. It looked at whether cells in the nose could help determine lung cancer risk in patients who have been given a CT scan. Around one in five lung CT scans find a nodule that could be cancer, but only around one in 25 of these nodules turn out to be a cancer. The researchers hope their approach could play a part in finding those cancerous nodules. We need new ways to understand which of the nodules are cancer, and reduce the number of potentially harmful tests such as biopsies or further imaging, which includes giving radiation.”