Lung cancer continues to be the leading cause of cancer deaths in the United States and worldwide. Because cancer treatments are most effective when the cancer is caught early, researchers have developed screening techniques that allow patients to be checked for some types of cancer before they have symptoms.
The technique used for lung cancer screening is called low-dose CT (LDCT). During an LDCT scan, you lie on a table and a machine uses a small amount of radiation to take many images, which it then compiles into a detailed picture of your lungs. The scan only takes a few minutes, and it is not painful or invasive. A radiologist can then read this picture to detect the presence of lung nodules.
LDCT scanning has been proven to be an effective way to screen high-risk individuals for lung cancer so that the cancer can be caught earlier when it is most treatable.
Who Should Be Screened?
The US Preventive Services Task Force recommends annual screening with LDCT for adults who:
- Are aged 55 to 80 years and
- Have a 30 pack-year smoking history* and
- Currently smoke or have quit within the past 15 years
*A pack year is the equivalent of one pack (20 cigarettes) smoked daily for one year. To have a 30-pack-year smoking history, a person could have smoked one pack daily for 30 years, two packs daily for 15 years, or any other combination of daily packs x number of years that totals 30.
Source: Screening & Early Detection
“The possibility of low-dose CT screening for lung cancer has been evaluated for over 3 decades,” says Pierre Massion, MD, professor of Medicine at Vanderbilt-Ingram Cancer Center and member of the LUNGevity Scientific Advisory Board. “In 2011, the results from the large randomized National Lung Screening Trial (NLST) provided strong evidence that LDCT scans can save lives.”
The NLST looked at using a low-dose CT scan (also called low-dose spiral CT or helical CT scan) to screen for lung cancer. Over 53,000 current and former heavy smokers aged 55 to 74 participated at 33 sites across the United States. Subjects were randomly assigned to receive three annual screens with either a low-dose CT scan or a standard chest X-ray. After a median of 6.5 years of follow-up, the results demonstrated that people who were screened with a low-dose CT scan had a 20% lower chance of dying from lung cancer than those who were screened with a chest X-ray.
Other studies have assessed the importance of lung cancer screening too. The NELSON trial, a Dutch–Belgian lung cancer screening trial (Nederlands–Leuvens Longkanker Screenings Onderzoek) studied the impact of LDCT screening on more than 15,000 individuals over 10 years. The findings, published in the New England Journal of Medicine in early 2020, showed that lung cancer-related mortality dropped by 24% in current and former smokers who had repeated lung cancer screenings, compared to those who did not undergo screening.
“LDCT is the standard practice for screening asymptomatic, high-risk individuals,” says Dr. Massion. Based on the data from the NLST, the NELSON trial and other studies, patients and physicians now have guidelines for lung cancer screening to clarify who will benefit most from a screening program.
Despite scientific studies and guidelines, there are many obstacles to getting people screened for lung cancer. One of the challenges in lung cancer screening is the high rate of false positive outcomes in which suspicious lung nodules detected on LDCT scans are studied further and found to be benign.
“Researchers are working to develop techniques to reduce the number of false positive results from LDCT scans,” explains Dr. Massion. Scientists are also trying to create new strategies and technologies to stratify the nodules found during lung cancer screenings into high-risk ”immediate-biopsy-needed” categories and low-risk “let’s-watch-and-wait” categories.
Some additional challenges to lung cancer screenings include coverage by insurance carriers, and patients’ understanding of the importance of repeated lung cancer screenings as part of a surveillance program.
“Nonprofits, such as LUNGevity, play a role in lobbying for policy changes such as improved insurance coverage, reducing insurance co-pays for lung cancer screenings, and combining this service with a smoking cessation program,” notes Dr. Massion. “It is also critical to continue educating individuals about the importance of lung cancer screening because the truth is lung cancer screening, even with all its challenges, saves lives.”
Related Reading:
- Screening & Early Detection
- Digital Technology Helps Improve Lung Cancer Pathology
- The Benefit of Early Detection
Juhi Kunde, MA, is a science writer for LUNGevity.