Expanded lung cancer screening guidelines designed to catch more cases early

Lung cancer screening
Expanded lung cancer screening guidelines may double the number of smokers at risk who can get screened for the disease.

The statistics on lung cancer may seem dire, but cancer experts have recently taken steps to turn that serious concern about a late diagnosis into an opportunity to help more patients. That’s why the U.S. Preventive Services Task Force (USPSTF) has developed expanded screening guidelines for lung cancer, hoping to double the number of smokers at risk who can get screened. The ultimate goal is to detect more lung cancers in earlier stages when treatment options have a better chance to produce positive outcomes.

The move marks an important change in approach to what the American Lung Association estimates is the most common cancer in the world. It’s also among the deadliest in the United States, for both men and women, largely because lung cancer is often diagnosed in advanced stages, making it more difficult to treat.  

“There has been a long history of a nihilistic attitude that nothing could be done for smoking-related lung cancer patients, but times have changed,” says Dan Miller, MD, Chief, General Thoracic Surgery at Cancer Treatment Centers of America® (CTCA), Atlanta. “There are so many new chemotherapy and immunotherapy drugs for individualized treatment options that can produce positive outcomes for more patients.”

In 2013, the USPSTF—an independent panel of experts that makes recommendations for clinical preventive services based on medical evidence—began recommending a low-dose CT (LDCT) scan every year for those deemed to be at highest risk for the disease, including:

  • Current Smokers between the ages of 55 and 79 with a 30 pack-year smoking history
  • Former smokers between the ages of 55 and 79 with a 30 pack-year smoking history who had quit within 15 years

The 2013 recommendations came after the task force examined the results of the eight-year National Lung Cancer Screening Trial of more than 50,000 participants. In that study, people received either three chest X-rays or three LDCT scans annually, to detect early stage lung cancers. Researchers concluded that those who got low-dose CT screenings were 20 percent less likely to die from lung cancer than those who got annual screenings with chest X-rays. Now, the USPSTF recommends:

  • The age to begin screening high-risk individuals with a low-dose CT scan be lowered from 55 to 50
  • The criteria for smoking history be reduced from a 30 pack-year habit to 20 pack-years

A pack-year measures how long and how much a person has smoked over a period of time. It’s calculated by multiplying the number of packs of cigarettes smoked per day by the number of years smoked. A pack-year calculator can be found here.

“Using the original National Lung Screening Trial guidelines would only detect between 8 percent to 12 percent of lung cancers in the US; by expanding the age criteria and decreasing the amount of smoking history, the percentage of lung cancer discovered should double or even triple,” Dr. Miller says, noting that at the time of diagnosis, 75 percent of lung cancer patients already have advanced disease, largely because patients usually only seek medical care when symptoms develop.

“The lungs have limited sensory nerves, so when a patient presents with symptoms such as weight loss, chest pain or coughing up blood, they’ve already developed advanced disease from a tumor within the lung,” he says. “With increased screening, you’re going to pick up patients at an earlier stage. Physcians involved with screening want to achieve a stage shift for lung cancer, thus diagnosing 75 percent of patients with early-stage disease and 25 percent with advanced stage. When the stage shift is successful, most of those patients can be treated with surgery, usually minimally invasive, and additional treatment with chemotherapy or radiation is not needed. This results in both a cost savings and a decrease in mortality.”

Dr. Miller says it’s important to educate each patient about the potential risks of low-dose radiation exposure and benefits of annual LDCT scans. For example, a single dose of a non-contrast CT scan has a low amount of radiation—less than 10 millisieverts (mSv), according to the U.S. Food and Drug Administration, or about three times the amount of natural radiation we’re exposed to in a year, but still less than 10 percent of the dose needed to significantly increase a person’s cancer risk.

However, in some cases, scans may produce a false positive. For instance, the scans could find benign lung nodules, which are common, especially in the South and Midwest. The concern is that false positives may subject patients to unnecessary and invasive procedures, such as biopsies. To reduce that likelihood, medical providers since 2015 have been using a ranking system known as the Lung Imaging Reporting and Data System (Lung-RADS®), developed by the American College of Radiology to establish standards for determining which lung nodules should be biopsied based on their size, characteristics and growth with subsequent scans.

The Lung-RADS system has helped reduce the number of unnecessary biopsies significantly since its introduction.

Dr. Miller says the expanded screening guidelines already are having an impact on those who have been diagnosed with lung cancer.

“The overall five-year lung cancer survival rates have improved, from less than 15 percent to greater than 20 percent, as we continue to screen more patients and find more earlier stage disease,” Dr. Miller adds. “Survival will continue to increase as the number of people who smoke decreases, which translates into fewer people with cancer, so it’s a win-win for everyone.”

Learn more about the expanded screening guidelines for cervical  cancer.