Diagnosis
Dr. Michael R. Johnston
MD, FRCSC Thoracic Surgeon, Halifax Nova Scotia
Lung Cancer Canada Board of Director
Lung Cancer Early Detection
Having treated many forms of cancer over the past 25 years, I have become aware of a regrettable paradox. Understandably, the earlier a cancer is diagnosed and treated, the better the results. However, early cancers rarely cause symptoms that might lead to a diagnosis. In lung cancer the unfortunate reality is that by the time patients develop symptoms, they often have far advanced disease. If only the tumour had been found before symptoms occurred, the outcome may have been much better.
This is the rationale for cancer early detection studies. It is widely used for cervical cancer (the Pap smear), breast cancer (mammography), colon cancer (occult blood) and prostate cancer (PSA). So now we are trying to do the same in lung cancer. This is not a new idea. It was tried before, and did not work. In the 1980’s a number of studies were done looking at yearly chest x-rays and sputum samples for signs of early lung cancer. Unfortunately, the methods were not very sensitive and therefore did not pick up tumours early enough to make a difference in outcome.
Today, we have better techniques and more sensitive detection methods. The most promising is called low-dose computer tomography (LDCT) and is being studied extensively around the world. It involves a typical CT scan of the chest, but is performed with a lower dose of radiation than the standard scan. The scan is repeated yearly and if a suspicious shadow is found, a biopsy is performed for diagnosis. Results so far show that very small lung cancers can be detected and treated. But there are still many questions to be answered before this can be considered a proven method.
Princess Margaret Hospital in Toronto is the site for one of these lung cancer early detection studies. They are accepting participants who are 55 years of age or older and who have at least a 10 year smoking history. For more information call (416) 946-4501 extension 6318 or email LungScreening@uhn.on.ca.
