If you’ve ever been a smoker, new research confirms that you can significantly reduce your risk of dying from lung cancer by getting an annual screening test called an “LDCT” scan. The scans catch cancer in people who may not have other symptoms.
An LDCT (“low-dose helical computed tomography”) scan is kind of like an x-ray (to get one, you lie on your back for about 30 seconds beneath a donut-shaped scanner).
Read MoreThe findings come from an extended, 11-year follow-up study of the large-scale National Lung Screening Trial. This is the study that originally found that, when it comes to lowering your risk of dying from lung cancer, these low-dose CT scans are more effective than straight forward chest x-rays.
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The National Lung Screening Trial was conducted by the American College of Radiology Imaging Network in combination with the National Cancer Institute (NCI)'s Lung Screening Study group. It first launched in 2002, at which point it enrolled 53,454 participants between the ages of 55 to 74 who were either current or former heavy smokers.
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At the time, these participants (who were screened at 33 different medical institutions all over the country) had no signs, symptoms, or histories of lung cancer. When they enrolled in the trial, they were randomly assigned to one of two groups: a chest x-ray group or a LDCT group.
Each group received its form of screening three times each year during the study.
When the primary results were published in the New England Journal of Medicine in 2011, they made a big splash.
The data showed that the people who received the LDCT screenings had a 15-to-20 percent lower risk of dying from lung cancer than the participants who received the x-rays did.
And in the wake of the study, the U.S. Preventative Serviced Task Force recommended annual LDCT screenings for heavy smokers (current or past) between the ages of 55 to 80.
But the study didn't end there. Though the assigned annual screenings were over, the researchers kept tabs on the outcomes of their participants, ultimately culminating in the long-term follow-up results, which were published last week in the Journal of Thoracic Oncology, the International Association for the Study of Lung Cancer (IASLC)'s official journal.
New Findings from the Follow-Up Study
For the most part, the extended follow-up for the National Lung Screening Trial reinforced the 2011 findings. But it also took them a step further.
Dr. Brendon Stiles, a thoracic surgeon at the Weill Cornell Medical Center, explained to SurvivorNet that because the follow-up tracked these participants for a longer period of time, the results suggest that screening with LDCT didn’t just delay lung cancer deaths, but actually prevented them (or at least delayed for more than a decade).
"[The screenings] continued to show a benefit for preventing lung cancer deaths," Dr. Stiles said. "This is remarkable given that the screening was only performed in the first three years and was not done continuously during the follow-up."
Dr. Stiles also pointed out that the primary results in 2011 had originally estimated based on their data that it would take screening 320 patients to prevent one death from lung cancer. But the follow-up research found that this number was actually closer to 303.
Dr. Paul Pinsky, chief of the early detection research branch at the NCI, said in a press release about the follow-up study, "Lung cancer is the leading cause of cancer death worldwide, and early detection and treatment through screening with [LDCT] has been investigated as a potential means of reducing lung cancer deaths for more than two decades. This study adds further weight to the notion that CT screening is effective."
Gender Differences In Lung Cancer Risk Reduction After CT Screening
Interestingly, Dr. Stiles also pointed out the screenings lowered the risk of dying from lung cancer slightly more for women than it did for men, which bolsters the results from another recent large-scale trial, called the NELSON Trial, which found that CT screenings over 10 years lowered women's risk of dying from lung cancer by 39 percent and lowered men's risk of dying from lung cancer by 26 percent.
Dispelling "Overdiagnosis" Myths: "A Very Important Detail."
In the wake of the primary lung screening trial’s results, some people zeroed in on the fact that more lung cancers were found generally with LDCT screening than with chest x-rays and used this to claim that LDCT screening was leading to "overdiagnosis"that is, labeling essentially harmless findings as cancer.
But Dr. Stiles pointed out that in the follow-up study, "the overall incidence of lung cancer in both arms was essentially identical after 11 years," and this data, published in the follow-up study, counter this claim.
"This concept that [LDCT] screening will find cancers that are indolent, or not clinically important, is frequently used to scare off people from [LDCT] screening and to suggest that it will lead to unnecessary health care spending," Dr. Stiles said. "But in fact, cancers in the [chest x-ray] arm caught up [in the follow-up study], suggesting that the excess cancers found in the CT arm eventually become clinically important. This is a very important detail."
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