Lung Cancer Screening with CT Lung Scan

Spiral CT scanning (more accurately called Helical CT) of the chest is a method of scanning patients for lung cancer that can detect lung cancers at an early stage.

Lung cancer is the number one cause of cancer death in American men and women, killing approximately 160,000 each year.  If the diagnosis is made early (stage I disease), the percentage of those alive five years after diagnosis 60-80%.  Unfortunately, lung cancers are often not detected until after symptoms appear, when the lung cancer is already at later stages and the cure rates are significantly lower.  The percentage alive in five years after a diagnosis of advanced disease is only 1-13%.  Without lung cancer screening, the percentage of lung cancers diagnosed with stage I disease is only 15%.  In a population of people screened yearly for lung cancer with CT, the percentage of cancers diagnosed with stage I disease rises to 75%.

Five-year survival rates are clearly different for diagnoses made at different stages.  However, there is some ongoing debate in the medical community and ongoing research as to whether screening for lung cancer is cost effective and whether detecting lung cancer at an earlier stage really makes a difference in overall survival.  It is possible that people diagnosed with lung cancer at an early stage using CT screening will still die at the same time they otherwise would have, except with a longer lead time between when they know of their disease and when they die.  Some argue that survival rate at five years after diagnosis is higher because of "lead time bias."  This argument is that the numbers only seem better because we start counting the five years at an earlier time, and not because earlier diagnosis lead to more effective intervention.  The fact that the number of lung cancers diagnosed each year is almost identical to the number of deaths from lung cancer each year (within 10%), suggests that almost everyone who gets lung cancer, even those diagnosed with early stage disease, dies of it.

While it seems intuitively obvious that earlier diagnosis should allow higher cure rates, the debate will continue for some time, until more definite long-term followup research data is available.

CT Lung Cancer Screening is performed at SDI Diagnostic Imaging in Oldsmar and SDI Diagnostic Imaging in South Tampa.