Put Lung Cancer to the Screening Test

Lung cancer screening for people at higher risk may reduce cancer related deaths

/ Author:  / Reviewed by: Joseph V. Madia, MD Chris Galloway, M.D.

(RxWiki News) Early diagnosis of lung cancer is extremely important. If the cancer is diagnosed at an early stage, it can be treated more effectively and patients can enjoy a better quality of life.

However, a majority of patients are diagnosed only after they show symptoms of lung cancer, when the cancer is already way beyond the early stages.

Routinely screening smokers and former smokers who are at high risk of developing lung cancer may reduce the number of lung cancer-related deaths, says a new study.

"Stop smoking today to lower risk of lung cancer."

This study was conducted by Linda L. Humphrey, MD, MPH, from the Department of Veterans Affairs along with colleagues and collaborators from the United States Preventive Services Task Force, and colleagues

The aim of this study was to find out whether screening individuals who were at high risk for lung cancer using low dose CT (computed tomography) scans reduced the number of lung cancer-related deaths and overall deaths.

A CT scan combines multiple x-rays taken from different angles to produce a cross-sectional image of bones and tissues inside the body.

Smoking is the most serious risk factor for lung cancer, as 85 percent of lung cancer cases occur due to smoking. Both current and former smokers have a higher risk of developing lung cancer.

For this study, the researchers looked at 67 previous studies published since 2000 to examine the benefits and ill effects of screening with low dose CT scans in high-risk adults who showed no symptoms.

Usually, tests such as low dose CT scans are used to catch lung cancer early. The biggest benefit to these screening tests is the early diagnosis and treatment of the cancer.

But these imaging techniques are associated with risks such as exposure to radiation, which itself can cause cancer.

Also, in some cases, the screening techniques might overdiagnose cancer or find other conditions that may be fine without any treatment. Such findings may cause a patient to undergo possibly unnecessary tests and treatments.

The researchers in the current study weighed these risks and benefits. Usually, in screening tests that have risks and benefits, researchers look at the number of screening tests used to prevent one death to see if the screening tests should be recommended.

Smokers were considered high risk for developing lung cancer by all the previous studies. Former smokers were considered high risk by the previous studies if they had quit smoking sometime in the past two decades or had smoked an average of one pack of cigarettes per day for more than 20 years. It must be noted that not all former smokers are at increased risk of developing lung cancer.

On review of the data, the researchers found that 320 low dose CT scan screenings were needed to prevent one lung cancer death. Also, 219 screenings were needed to prevent one overall death due to any cause.

According to the researchers, this number was comparable to the number of screening tests needed to prevent one death in breast cancer and colon cancer.

The researchers concluded that screening adults who have no symptoms but are at risk for lung cancer using low dose CT scans may reduce the number of deaths in the population.

The researchers noted that if lung cancer screening becomes routine, more research must be conducted to identify the harmful effects of screening and how to reduce them.

“The US Prevention Services Task Force should be applauded for coming out recommending lung cancer screening for high-risk individuals. The recommendations are in full harmony with previous statements and recommendations from other organizations, among them The International Association for the Study of Lung Cancer,” says Fred R. Hirsch, MD, PhD, Professor of Medicine at the University of Colorado and CEO Elect of IASLC.

“It is important that the candidate individuals discuss the matter with their doctors in order to be fully informed about potential risks and benefits. Still there is a high false positive rate of screened detected nodules and ongoing studies with improved technology and assessments will most likely reduce the false positive rates,” Dr. Hirsch notes.

False positives occur when a person who does not have lung cancer is diagnosed as having lung cancer after examination of the CT scan. Such patients may undergo further tests to confirm the diagnosis or make sure they don’t have lung cancer. 

This study was published July 29 in the Annals of Internal Medicine.

The research was funded by the Agency for Healthcare Research and Quality. The authors disclosed employment and consulting relationships with the Department of Veterans Affairs and other public organizations. However, the Department of Veterans Affairs had no role in conducting this study.

Review Date: 
July 29, 2013
Last Updated:
July 30, 2013