Overview

Spiral CT scanning of the chest is an emerging method of scanning patients for lung cancer that has shown potential in detecting early stage lung cancers in high-risk patients.

Lung cancer is diagnosed in 178,000 Americans every year, and kills approximately 160,000. The percentage of those alive five years after diagnosis with stage I disease is 60-80%. Lung cancers are usually detected after symptoms appear which may be in later stages of cancer when cure rates are the lowest. The percentage alive in five years after a diagnosis of advanced disease is only 1-13%. However, the percentage of patients diagnosed with stage I disease is only 15%. In a population of people screened yearly for lung cancer with CT, the percentage diagnosed with stage I disease is 75%.

Research on the medical effectiveness and economic cost effectiveness of CT Lung Cancer Screening continues. The simplistic math is very impressive. CT screening studies could increase the percentage of people diagnosed with stage I disease from 15% to 75% of total diagnoses. 65% down staging multiplied by a 50% decrease in mortality multiplied by 178,000 cases a year could mean a savings of at least 55,000 lives a year - a huge benefit compared to screening for any other cancer. The best-case scenario translates to a cost per life-year saved of as low as $2,000, compared to $30,000 (using optimistic assumptions) for mammography.

Unfortunately, these assumptions have not been clinically proven. It is possible that people diagnosed with lung cancer using CT screening studies will die at exactly the same time they otherwise would have, except with a longer lead time between when they know of their disease and when they die. The fact that the incidence of lung cancer is almost identical to the mortality rate from lung cancer (within 10%), suggests that almost everyone who gets lung cancer, even those diagnosed with early stage disease, dies of it.

Prospective randomized trials of actual survival are currently underway, but they won’t achieve preliminary results for five years, with final results at least ten years away. Clearly the controversy will be with us for a long time.