The chair of the ACR Lung-RADS Committee dives into the importance of early lung cancer detection through screening.
Alan H. Matsumoto, MD, MA, FACR
From the Chair of the Board of Chancellors
Alan H. Matsumoto, MD, MA, FACR
After presenting one of my first scientific abstracts as a second-year radiology resident at a professional society meeting in the early 1990s, I was approached by a well-established professor of radiology who asked me some questions about it. He then asked what specialty I was going into. When I said chest radiology, he said something along the lines of “What a waste, it’s just a lot of ICU chest X-rays.” So, I retorted, “The leading causes of death in the U.S. are cardiovascular disease, cancer, and respiratory disease, all of which can be found in the chest where I can make an impact.” I’m not sure who was more startled, him or me! I also didn’t realize it at the time, but this was something that would follow me through my career as a cardiothoracic radiologist.
Fast forward. Lung cancer is the leading cause of cancer death in the U.S. in both men and women. It causes more cancer deaths than the second through fourth leading causes of cancer death combined. You’d probably be surprised to learn that lung cancer deaths in individuals who never smoked is the fifth leading cause of cancer death, chest CT scans are the most effective way to reduce cancer deaths in the U.S. by the combination of lung cancer screening and early lung cancer detection through incidental pulmonary nodule detection and management.
I’ve been fortunate to be part of the science that brought this to fruition as the site principal investigator at the University of Michigan for the National Lung Screening Trial. Those results were published in the New England Journal of Medicine in August 2011, demonstrating a 20% mortality reduction. The ACR was central to that work through the ACR Imaging Network (ACRIN). It was immediately evident that proving the value of screening scientifically didn’t mean it would be out into practice right away without a U.S. Preventative Services Task Force (USPSTF) recommendation — and coverage and payment policy… and that meant advocacy, something I hadn’t been involved in before. That also meant quickly harnessing the power of the ACR’s knowledge and resources to develop a clinical practice guideline and quality structure for lung cancer screening. By 2014, we had developed Lung-RADS® for radiologists to use as a structured reporting and management tool for reading lung cancer screening CTs. This addressed concerns from the CMS Medicare Evidence Development & Coverage Advisory Committee about over testing and complications from inappropriate follow-up testing and procedures. The ACR Lung Cancer Screening Registry was born out of the CMS coverage decision that required participating in a registry to evaluate the quality of lung cancer screening in its formative years. We tied it to Lung-RADS, launched it within a few months of the CMS decision and made it the de facto interpretation tool used across the U.S. Soon after, the Lung Cancer Designation as part of the CT Accreditation program was developed, the ACR-Society of Thoracic Radiology Practice Parameter for the Performance and Reporting of Lung Cancer Screening Thoracic CT followed and an ACR free, online education tool for radiologists was released. Wow! But that was the easy part. Advocacy for a USPSTF recommendation meant building critically important partnerships — with organizations including the GO2 for Lung Cancer, the Society of Thoracic Surgeons, the American Cancer Society, the American Thoracic Society and the American College of Chest Physicians — so that we could speak as one voice and be successful together and harness the power of the ACR’s government relations and economics teams. At the end of December 2013, the USPSTF recommended screening and the CMS coverage decision came out in early 2014.
The ACR Lung Cancer Screening Registry was born out of the CMS coverage decision that required participating in a registry to evaluate the quality of lung cancer screening in its formative years.
The most recent 2021 USPSTF recommends lung cancer screening for individuals aged 50–80 years who have a 20 or greater pack-year history of cigarette smoking and either currently smoke or quit within the last 15 years. This was an expansion of their first 2013 recommendation that started at 55 years of age and 30 or more pack years. In its update, they acknowledged that Black Americans, women and other subpopulations were at a high risk of lung cancer with a different pack year history and at a lower age, with these changes designed to address health equity. More recent analysis of the impact has shown that it did expand lung cancer screening to these populations, but it also increased the number of White individuals being screened. With the recently updated American Cancer Society lung cancer screening guideline that dropped the years since quitting criterion, approximately 19.2 million people are now eligible for lung cancer screening. Evidence shows that people’s lung cancer risk continues to increase as they get older, yet they are being dropped from screening eligibility the longer they are out of smoking. So, we are back at it again with advocacy efforts to the USPSTF to drop the years since quitting criterion among other things, and we are already engaging the CMS coverage group which can consider action once a USPSTF change occurs.
But that is not all chest CTs can do to impact mortality. Other findings on chest CTs performed every day and described as “incidental” to the reason the exams were performed, impact both morbidity and mortality. These can be visually detected and reported by radiologists and enabled by AI detection tools. First and foremost are incidentally detected pulmonary nodules or “IPNs,” which are an equally key component of early lung cancer detection. Uncovered every day on routine chest CTs — and to a lesser extent other imaging exams that include portions of the lungs — guideline-based nodule follow-up is critical to early cancer detection, with delays or failure to manage these IPNs resulting in later stage cancer detection and patient harm. There is no better evidence than the side-by-side prospective clinical study of lung cancer screening and IPN programs run across Baptist Memorial Health Care facilities known as the DELUGE study. Over six years, 5,659 patients were enrolled in the screening program, which found 150 lung cancers, of which 61% were early stage. During the same time period, 15,461 patients were in the IPN program, and 698 patients were found to have lung cancers, of which 60% were in the early stage.
Coronary artery calcification (CAC) is an important common “incidental” finding on chest CT exams that all radiologists should report by providing a visual score of none, moderate or severe in their reports. This CAC visual score correlates with the atherosclerotic cardiovascular disease risk calcium scoring categories and is an opportunity to identify patients who may benefit from aggressive cardiovascular risk factor modification, such as the initiation of statin medication.
More recently, AI-enabled quantitative scoring is now possible on all chest CTs, akin to the traditional CAC score. In the lungs, findings of both obstructive and interstitial lung disease lead to early diagnosis and disease management that also impacts mortality. Lastly, bone mineral density can be measured by placing a region of interest on the L1 vertebral body to detect early osteoporosis and osteopenia, providing a chance to initiate medical treatment at an earlier stage for bone fragility and reduce the incidence of spine and hip fractures and their attendant morbidity and mortality.
Growing up in metropolitan Detroit, the automobile capital of the U.S., this phrase seems appropriate: Today’s chest CT is not your father’s Oldsmobile… it’s so much more!
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