February 25, 2013 | by Hiu Chung So
Lung cancer incidence and deaths have declined in recent years — due to declining tobacco consumption — but lung cancer remains the second most commonly occurring cancer and the leading cause of cancer deaths in the United States. This year, it is expected to kill almost 160,000 Americans.
Tobacco avoidance and smoking cessation are the most effective ways to reduce future lung cancer cases and deaths, but researchers also are assessing whether regular screenings can help by detecting lung cancer at its earliest and most treatable stages.
According to a study published online Feb. 25 in the journal Cancer, the American Cancer Society’s peer-reviewed journal, screening with low-dose computed tomography (CT) could save more than 12,000 lives each year if every screening-eligible American received an annual scan.
To determine this figure, the researchers used 2010 U.S. Census data, results of the National Lung Screening Trial and multiple national health surveys to determine screening eligibility and lung cancer mortality rates among current and former smokers.
“This publication is significant in that it translates the lifesaving benefit of lung cancer screenings into a number of lives saved per year," said Dan J. Raz, M.D., co-director of City of Hope’s Lung Cancer and Thoracic Oncology Program.
But Raz, who was not involved in the study, said the findings may be too conservative.
"In my opinion, this study significantly underestimates the potential lifesaving benefit of lung cancer screening with low-dose CT scanning because it uses the strict criteria established by the National Lung Screening Trial," he said. "In that study, a very limited group of at-risk patients were screened, and they were screened for only three years. Additional research is needed on determining the best criteria to screen patients so that the maximum benefit of lung cancer screening can be derived for people who may be at risk for lung cancer."
Other experts agree that more data is needed too, but for different reasons.
CT scans expose patients to higher levels of radiation compared to standard chest X-rays, and they can produce false positives, leading to unnecessary further tests and procedures. CT scans are pricey, too — approximately $300 to $500 per scan — and aren't covered by most insurance, so clinicians and researchers are still trying to a find a cost-effective way to implement a screening program.
But co-author Ahmedin Jemal, D.V.M., Ph.D., told Everyday Health that the benefits of low-dose CT scans for high-risk populations outweigh the risks. “The patient should know the benefit as well as the harm” before making a decision with his or her doctor, Jemal said.
In the meantime, the American Lung Association recommends that current or former smokers 55 to 74 years old with a history of 30 pack-years (i.e., the equivalent of a pack a day over 30 years) should consider low-dose screening for lung cancer.
It makes those recommendations based on the results of the aforementioned National Lung Screen Trial, which showed that low-dose CT scans can reduce lung cancer deaths by 20 percent compared to normal chest X-rays among heavy smokers.