Dr. Ella Kazerooni knows a thing or two about looking for lung cancer. As the chair of the American College of Radiology’s committee on lung cancer screening, she has been at the forefront of giving doctors the tools they need to diagnose high-risk patients early.
One of those tools for which she has long been fighting to use is low-dose computed tomography (CT), which images the body in virtual slices using x-rays. She was convinced of their benefit by a massive study called the National Lung Screening Trial that compared two different types of screening. It involved 53,000 heavy smokers aged 55 to 74 years who ran a high lung cancer risk. The study found that people who underwent an annual low-dose CT scan were 20 percent less likely to die from lung cancer than those screened with a standard chest x-ray.
“Bringing low dose CT screening to patients at a high risk for lung cancer will reduce death from the most deadly cancer worldwide,” she said. Indeed, decreasing mortality by the percentage seen in the lung screening trial could keep as many as 32,000 people alive of the more than 158,000 expected by the American Cancer Society to die of lung cancer this year in the U.S. alone.
Top, above and below: : Illustrative CT lung images showing lung nodules (upper right lung corner in top image). These images were not acquired as part of low dose CT lung cancer screening and are not representative of typical screening images. They have been post-processed using software applications that are not necessary for lung cancer screening. Image credit: GE Healthcare
This significant improvement in lung cancer patient outcomes arises from the ability of doctors to use CT to detect small lung nodules that they can’t see on standard x-rays.
Recognizing these abnormalities while they are still small allows doctors to detect lung cancer in its earliest stages when it can be more effectively treated and cured. CT can also be used to more accurately measure a nodule’s change in size over time—a key diagnostic parameter since malignant nodules grow faster than benign ones. Catching the disease early is often the difference between life and death for sufferers. The overall five-year lung cancer survival rate is just 17 percent, among the most deadly of all cancers. But chances improve greatly when it is found at an early stage, with the five-year survival rate at 54 percent. i, ii
Unfortunately, up until recently, doctors who wanted to use CT scanners to look for the early signs of lung cancer had to go it alone—since the machines weren’t sanctioned to be used for that purpose by the U.S. Food and Drug Administration (FDA). As a result, doctors couldn’t ask scanner manufacturers how best to use the equipment for lung screening.
“Performing low dose CT with attention to high image quality at the lowest radiation exposure to detect early cancer is at the core of a successful screening program, and requires collaboration with the entire imaging community to bring technology to bear for this purpose,” said Kazerooni.
GE Healthcare knew that collaborating with customers on low dose CT lung cancer screening was critical to customers’ success in setting up effective screening programs. A cross-functional team spent countless hours gathering data to submit to the FDA and just recently announced that GE Healthcare was the first company to receive FDA clearance for low dose CT lung cancer screening. It’s also the first time in history that any CT device has received FDA clearance for any screening indication.
“The National Lung Screening Trial really gave doctors and healthcare organizations the clinical evidence they needed to urge the FDA to clear CT scanners for lung cancer screening,” says Ken Denison, the molecular imaging and CT dose leader at GE Healthcare, one of the major manufacturers of CT machines. “Lung cancer kills more people annually than the next three deadliest cancers combined. So reducing the mortality rate by 20 percent is definitely one of the most important direct health impacts CT screening can have.”
Using low dose CT for screening was initiated when the U.S. Preventative Services Task Force and the Centers for Medicare and Medicaid Services recommended the use of low dose CT lung cancer screening for high-risk individuals. Medicare will now reimburse eligible beneficiaries who undergo the test.iii
Denison says there is still a while to go before the switch from old-fashioned x-rays to CT scans is complete. “If history is any guide, this could take five to 10 years before diagnosticians generally use CT for lung cancer screening instead of chest x-rays in the U.S.,” he says. “To get to the point of saturation, that tends to be how slowly adoption moves. The important thing is that doctors can now begin to take advantage of this great technology.”
i American Cancer Society. Cancer Facts and Figures 2015.
ii National Cancer Institute. Surveillance, Epidemiology, and End Results Program (SEER). SEER Stat Fact Sheets: Lung and Bronchus Cancer. http://seer.cancer.gov/statfacts/html/lungb.html
iii CMS has determined that those beneficiaries who are 55-77, asymptomatic, have a tobacco smoking history of at least 30 pack-years, are a current smoker or one who has quit smoking within the last 15 years; and receives a written order for LDCT lung cancer screening may receive an annual screening for lung cancer with low dose computed tomography (LDCT), as an additional preventive service benefit under the Medicare program. – CMS: Decision Memo for Screening for Lung Cancer with low dose Computed Tomography (LDCT) (CAG-00439N)