Low-dose CT scanning detects cancers long before symptoms ever appear

Early screening for lung cancer using non-invasive, low-dose CT scanning detects early stage cancers long before symptoms ever appear, according to results of a clinical study with 1,000 high-risk Canadian smokers.

The findings of the study led by radiologist Heidi Roberts at Princess Margaret Hospital (PMH), University Health Network are published in the October issue of the Canadian Association of Radiologists Journal.

“It is often too late to save lives when people become aware of symptoms. This is why early detection is so important,” says Dr. Roberts. “The sooner lung cancer is detected, the easier it is to treat, often less invasively, and certainly more cost- effectively.”

Beginning in 2003, the study enrolled 1,000 Canadian smokers aged 55 and older, who had smoked at least a pack a day for 10 years. The study found that 26% of participants needed further testing, and 2.2% had cancer, which was treated in the meantime. A total of 3,600 Canadians have now been screened at PMH, the only Canadian site involved in the International Early Lung Cancer Action Program. The study oversees more than 35,000 participants worldwide.

Low-dose CT scanning takes 30 seconds, and shows several hundred, 1-mm thin cross-sectional images of the lungs from top to bottom, whereas a conventional X-ray only shows two views of the chest.

Lung cancer is the most common cause of cancer death among Canadians. However, when caught early, it can be cured.

The PMH screening program was made possible by a donation from the friends and family of Lusi Wong, dedicated to the early diagnosis of lung cancer.