Lung Cancer Screening
Lung cancers tend to grow silently, not causing any symptoms while still at an early and more curable stage. A large medical study published in 2011 involving more than 53,000 people deemed to be at higher risk for lung cancer compared yearly CT scans to yearly chest xrays as a screening test designed to find lung cancers at a more curable stage.
The results showed that compared to the group screened with annual chest x-rays, the patients who had yearly CT scans had 20% less deaths due to lung cancer, and 6.7% less deaths of all causes. However, there were many “false positives” in the CT scan group: in 24% of people getting CT scans, there were lung nodules (small spots on the CT scan) that might be cancer. Fortunately only 4% of those lung nodules found turned out to be cancer. Finding any lung nodule on CT scan may not only create anxiety, they may generate more tests, or invasive procedures. Trying to determine whether or not a lung nodule is likely to be cancerous usually requires specialty care by a Pulmonologist. To help with this problem, we formed a Lung Nodule Clinic.
So a yearly CT scan in people at risk for lung cancer can reduce deaths due to lung cancer by 20%. But in about 24% of people getting a CT scan, we will find spots that may cause “false alarm” because we can’t tell initially if they are cancerous or not. Most of the time, they are not cancerous. Currently the U.S. Preventive Services Task Force recommends yearly lung cancer screening with LDCT for people who—
- Have a history of heavy smoking, and
- Smoke now or have quit within the past 15 years, and
- Are between 55 and 80 years old.
Heavy smoking means a smoking history of 30 pack years or more. A pack year is smoking an average of one pack of cigarettes per day for one year. For example, a person could have a 30 pack-year history by smoking one pack a day for 30 years or two packs a day for 15 years.