This year, more than 26 thousand Canadians will be diagnosed with lung cancer and close to 21 thousand will die of it. That's according to the Canadian Cancer Society. A controversial new set of screening guidelines just published in the Canadian Medical Association Journal say doctors should do more to save lives.
The guidelines come from the Canadian Task Force on Preventive Health Care established by the Public Health Agency of Canada to develop guidelines to help prevent serious conditions like cancer and heart disease. The idea behind the guidelines is to detect lung cancers when they're tiny and perhaps more curable.
Some say the new guidelines put Canadians at risk. The National Lung Screening Trial which was cited by the article found that for every 1000 people who get three low dose CT scans in three years,391 will have at least one positive scan. Of those, 40 will have confirmed lung cancer, but 351 will have a false positive result. That means the CT scan finds something that looks like a cancer but further testing shows no cancer. The confirmatory tests are invasive; they include bronchoscopy in which the patient is sedated and a bronchoscope is passed through the mouth and into the bronchial passages as well as biopsies.
In the study I just mentioned, three out of every 1000 people screened for lung cancer with low dose CT scan had a major complication from invasive testing, and one per 1000 died as a result of the invasive test. There's also the risk of radiation exposure from the CT causing a fatal cancer at a rate of about one in 2,000.
These new recommendations are highly significant given society's attitude toward smokers. I'm sure some people would question spending public money to do expensive CT scans to screen for lung cancer given that 85 per cent of the 26,000 lung cancers diagnosed in Canada each year are caused by smoking.
I have two answers to that. First, we spend a lot of public money treating other diseases associated with diet, weight and alcohol consumption. I'm not sure it's fair to single out smoking. Second, a lot of the people who are eligible for screening are ex-smokers who quit in the past fifteen years. For that, I think we owe it to them to look for cancers that are potentially curable. As for current smokers, screening them for lung cancer provides an excellent opportunity encourage them to quit. I'm all for it.