Things you should know about lung cancer screening

What are the benefits of screening?

For people who are eligible for screening and decide to get screened, the chances of finding cancer early is higher. Finding cancer early generally means that there are more treatment options available. A recent study showed that after 6.5 years, among those who were eligible for screening, those who were screened with CT were 20% less likely to die from lung cancer compared to those who were not screened with CT.

What are the harms of screening?

Lung cancer CT screening only helps to find cancer if it is already there. It cannot prevent cancer. The only way to prevent cancer is to stop smoking if you have not already done so. Screening uses a CT scan which uses a lower dose of X-Ray radiation than a conventional CT scan. The additional risk of developing fatal lung cancer from one adult exam is low enough that it is difficult to measure, with the estimated chances being between 1 in 100,000 to 1 in 10,000. For those of you interested in the total dose of radiation, you can visit this site. Other potential harms from screening include: false alarms, overtreatment, more testing, and invasive procedures.

False alarms

Screening works by finding lung nodules, some of which are cancer, but the vast majority (over 96%) of nodules detected on screening are not cancer. These false positive findings outnumber cancers 25 to 1. False positive findings have the potential to cause anxiety. However, understanding that the vast majority of lung nodules found on CT screening do not represent cancer helps most patients avoid significant anxiety while they wait for follow-up testing.

Overtreatment (or Overdiagnosis)

There are times when screening will find a nodule that looks like cancer but was never going to cause problems. This can lead to treatments such as surgery, chemotherapy, and radiation which are unnecessary and considered overtreatment. Overtreatment can cause side effects that make you feel sick.

More testing

In order to prove a nodule is not cancer, the proper recommendation is generally to take additional follow up scans to monitor for changes. Your doctor will make recommendations for the proper follow up interval to monitor any lung nodules detected. Most often, this is at 6-month to 12-month intervals.

Invasive procedures

Sometimes further testing for a finding on lung cancer screening leads to the need for additional testing that can include invasive procedures (biopsies or surgery). These tests are risky and can cause harm in people that end up not having had cancer. Invasive procedures can result in minor complications such as bleeding and infections. They can also result in more major complications such as a collapsed lung and even death.

For more details, you can visit the Q & A compiled by the National Cancer Institute that explains the findings from the national lung Screening trial.