To screen, or not to screen?

The debate over lung cancer screening

Lung cancer is the leading cause of cancer related death among both men and women. By the time most patients are diagnosed with lung cancer, it is usually rather advanced and becomes difficult to treat. Detecting lung cancer at earlier stages has the potential to make a significant impact on death rates from the disease.

For years there was hope that chest x-rays would be an effective screening tool, but several studies found it to be ineffective. As imagining technology evolved, low-dose CT scans (LDCT) quickly becomes the most promising tool to screen for lung cancer. Several studies have been conducted to determine if using LDCT to screen for lung cancer would save lives. Results from the National Lung Cancer Screening Trial (NLST) found that among smokers and former smokers who are age 55 to 74, have smoked for 30 pack years or more (pack years are calculated by multiplying the number of packs a person smokes or has smoker per day by the number of years they’ve been smoking, so thirty pack years would be equal to a person who smoked a pack a day for thirty years, or 2 packs a day for 15 years) and either still smoke or have quit smoking within the past 15 years, yearly screening with LDCT can reduce their risk of lung cancer related death¹.

While these results are promising, there were also several drawbacks and complications associated with LDCT that are equally important to take into consideration. The images produced by LDCT will not only make tumors visible, but also other benign, or non-threatening lesions, or spots.  It’s been estimated that of those screened with LDCT, 20% will screen positive and need some sort of follow-up². The required follow-up will consist of additional tests and surgical procedures. These tests and surgical procedures all have their risks and could result in potentially serious complications. Only 1% will actually have lung cancer.  The burden placed on those who required follow-up, but turned out not to have lung cancer, is not trivial. Dr. Herald Varmus, Director of the National Cancer Institute, was quoted as saying, “There are economic, medical, and psychological consequences of finding these abnormalities” to the New York Times in an interview shortly after the results of the NLST were released.

Estimates from a national survey indicate that approximately 8.7 million Americans would be eligible for lung cancer screening with LDCT based on the results of the NLST³. At a cost of about $300 to $500 dollars per LDCT², there is some concern that screening this many people could overwhelm the healthcare system.  Without an official guideline, it’s unclear if insurance will cover the screening test. Also, the eligibility criteria for screening are rather complicated and may not be well implemented, likely resulting in unnecessary screening. There is also concern that the availability of a screening test for lung cancer will give smokers a reason not to quit.

Additional analyses and studies will need to be conducted in order to determine if lung cancer screening with LDCT is viable and safe. In the mean time, avoiding smoking or quitting altogether remains the most effective way to prevent lung cancer and not have to worry about lung cancer screening.

Juan Rodriguez is a doctoral student in Behavioral Science and Health Education at Emory University. He is an avid watcher of the reality TV show Hoarders because he lives in fear that his wife will one day become a hoarder. 

Sources

1 – National Lung Screening Trial Research Team. (2011) Reduced Lung-Cancer Mortality with Low-Dose Computer Tomographic Screening. New England Journal of Medicine. 365(5):395-409.

2 – Bach PB, Mirkin JN, Oliver TK, Azzoli TK, Berry DA, Brawley OW, Byers T, Colditz GA, Gould GA, Jett JR, Sabichi AL, Smith-Bindman R, Wood DE, Qaseem A, Detterbeck FC. (2012) Benefits and harms of CT Screening for Lung Cancer: A Systematic Review. JAMA. 307(22):E1-E12.

3 – Doria-Rose VP, White MC, Klabunde CN, Nadel MN, Richards TB, McNeel TS, Rodriguez JL, Marcus PM. (2012) Use of Lung Cancer screening tests in the United States: Results from the 2010 National Health Interview Survey. Cancer Epidemiology, Biomarkers and Prevention. 21(7):1049-1059.