New research suggests lung cancer in non-smokers appears to be a different disease compared to the lung cancer that affects smokers, raising the possibility the two groups should be treated differently.
Researchers at the BC Cancer Agency Research Centre examined the DNA of lung cancer tumours from 83 patients, 30 of whom never smoked.
When they compared the cancer cells with healthy cells from the same patients, they found differences in how the cancer DNA had been altered, depending on whether the patient smoked.
The researchers found that the tumours in patients who have never smoked had twice as many DNA abnormalities as those in people who were current or former smokers.
It's thought that the carcinogens in tobacco and cigarettes cause DNA mutations that lead to the uncontrolled growth of cancer cells. In non-smokers, the added genetic mutations suggest other mechanisms are driving the tumor growth.
The findings were presented this week at an American Association of Cancer Research conference in Philadelphia.
Researcher Kelsie Thu says although the research is preliminary, the fact that the DNA of cancer cells is different between smokers and non-smokers suggests they could be treated as different diseases.
"A better understanding of the biology underlying lung cancer development will lead to improved detection and therapeutic strategies, and ultimately, will result in improved patient prognosis," she said in a news release.
"Hopefully, our findings will stimulate the research community to further investigate the differences between lung cancer in these two cohorts, which could ultimately lead to the discovery of novel molecular targets for the diagnosis and treatment of lung cancer in never-smokers," Thu said.
About 15 per cent of those diagnosed with lung cancer never smoked. Research has shown that non-smokers with lung cancer are more likely to be female and young, for reasons not yet understood.
Understanding the differences between the cancers is expected to become even more important as smoking rates continue to fall and the proportion of lung cancer patients who have never smoked increases.
With files from the Canadian Press
