Dr. Nathan Pennell and Dr. Cheryl Czerlanis discuss challenges in lung cancer screening and potential solutions to increase screening rates, including the use of AI to enhance risk prediction and screening processes.
Transcript
Dr. Nate Pennell: Hello, and welcome to By the Book, a monthly podcast series for ASCO Education that features engaging discussions between editors and authors from the ASCO Educational Book. I'm Dr. Nate Pennell, the co-director of the Cleveland Clinic Lung Cancer Program and vice chair of clinical research for the Taussig Cancer Center. I'm also the editor-in-chief for the ASCO Educational Book.
Lung cancer is one of the leading causes of cancer-related mortality worldwide, and most cases are diagnosed at advanced stages where curative treatment options are limited. On the opposite end, early-stage lung cancers are very curable. If only we could find more patients at that early stage, an approach that has revolutionized survival for other cancer types such as colorectal and breast cancer.
On today's episode, I'm delighted to be joined by Dr. Cheryl Czerlanis, a professor of medicine and thoracic medical oncologist at the University of Wisconsin Carbone Cancer Center, to discuss her article titled, "Broadening the Net: Overcoming Challenges and Embracing Novel Technologies in Lung Cancer Screening." The article was recently published in the ASCO Educational Book and featured in an Education Session at the 2025 ASCO Annual Meeting. Our full disclosures are available in the transcript of this episode.
Cheryl, it's great to have you on the podcast today. Thanks for being here.
Dr. Cheryl Czerlanis: Thanks, Nate. It’s great to be here with you.
Dr. Nate Pennell: So, I'd like to just start by asking you a little bit about the importance of lung cancer screening and what evidence is there that lung cancer screening is beneficial.
Dr. Cheryl Czerlanis: Thank you. Lung cancer screening is extremely important because we know that lung cancer survival is closely tied to stage at diagnosis. We have made significant progress in the treatment of lung cancer, especially over the past decade, with the introduction of immunotherapies and targeted therapies based on personalized evaluation of genomic alterations. But the reality is that outside of a lung screening program, most patients with lung cancer present with symptoms related to advanced cancer, where our ability to cure the disease is more limited.
While lung cancer screening has been studied for years, the National Lung Screening Trial, or the NLST, first reported in 2011 a significant reduction in lung cancer deaths through screening. Annual low-dose CT scans were performed in a high-risk population for lung cancer in comparison to chest X-ray. The study population was comprised of asymptomatic persons aged 55 to 74 with a 30-pack-year history of smoking who were either active smokers or had quit within 15 years. The low-dose CT screening was associated with a 20% relative risk reduction in lung cancer-related mortality. A similar magnitude of benefit was also reported in the NELSON trial, which was a large European randomized trial comparing low-dose CT with a control group receiving no screening.
Dr. Nate Pennell: So, this led, of course, to approval from CMS (Centers for Medicare and Medicaid Services) for lung cancer screening in the Medicare population, probably about 10 years ago now, I think. And there are now two major trials showing an unequivocal reduction in lung cancer-related mortality and even evidence that it reduces overall mortality with lung cancer screening. But despite this, lung cancer screening rates are very low in the United States. So, first of all, what's going on? Why are we not seeing the kinds of screening rates that we see with mammography and colonoscopy? And what are the barriers to that here?
Dr. Cheryl Czerlanis: That's a great question. Thank you, Nate. In the United States, recruitment for lung cancer screening programs has faced numerous challenges, including those related to socioeconomic, cultural, logistical, and even racial disparities. Our current lung cancer screening guidelines are somewhat imprecise and often fail to address differences that we know exist in sex, smoking history, socioeconomic status, and ethnicity. We also see underrepresentation in certain groups, including African Americans and other minorities, and special populations, including individuals with HIV. And even where lung cancer screening is readily available and we have evidence of its efficacy, uptake can be low due to both provider and patient factors. On the provider side, barriers include having insufficient time in a clinic visit for shared decision-making, fear of missed test results, lack of awareness about current guidelines, concerns about cost, potential harms, and evaluating both true and false-positive test results.
And then on the patient side, barriers include concerns about cost, fear of getting a cancer diagnosis, stigma associated with tobacco smoking, and misconceptions about the treatability of lung cancer.
Dr. Nate Pennell: I think those last two are really what make lung cancer unique compared to, say, for example, breast cancer, where there really is a public acceptance of the value of mammography and that breast cancer is no one's fault and that it really is embraced as an active way you can take care of yourself by getting your breast cancer screening. Whereas in lung cancer, between the stigma of smoking and the concern that, you know, it's a death sentence, I think we really have some work to be made up, which we'll talk about in a minute about what we can do to help improve this.
Now, that's in the U.S. I think things are probably, I would imagine, even worse when we leave the U.S. and look outside, especially at low- and middle-income countries.
Dr. Cheryl Czerlanis: Yes, globally, this issue is even more complex than it is in the United States. Widespread implementation of low-dose CT imaging for lung cancer screening is limited by manpower, infrastructure, and economic constraints. Many low- and middle-income countries even lack sufficient CT machines, trained personnel, and specialized facilities for accurate and timely screenings. Even in urban centers with advanced diagnostic facilities, the high screening and follow-up care costs can limit access. Rural populations face additional barriers, such as geographic inaccessibility of urban centers, transportation costs, language barriers, and mistrust of healthcare systems. In addition, healthcare systems in these regions often prioritize infectious diseases and maternal health, leaving limited room for investments in noncommunicable disease prevention like lung cancer screening. Policymakers often struggle to justify allocating resources to lung cancer screening when immediate healthcare needs remain unmet. Urban-rural disparities exacerbate these challenges, with rural regions frequently lacking the infrastructure and resources to sustain screening programs.
Dr. Nate Pennell: Well, it's certainly an intimidating problem to try to reduce these disparities, especially between the U.S. and low- and middle-income countries. So, what are some of the potential solutions, both here in the U.S. and internationally, that we can do to try to increase the rates of lung cancer screening?
Dr. Cheryl Czerlanis: The good news is that we can take steps to address these challenges, but a multifaceted approach is needed. Public awareness campaigns focused on the benefits of early detection and dispelling myths about lung cancer screening are essential to improving participation rates. Using risk-prediction models to identify high-risk individuals can increase the efficiency of lung cancer screening programs. Automated follow-up reminders and screening navigators can also ensure timely referrals and reduce delays in diagnosis and treatment. Reducing or subsidizing the cost of low-dose CT scans, especially in low- or middle-income countries, can improve accessibility. Deploying mobile CT scanners can expand access to rural and underserved areas.
On a global scale, integrating lung cancer screening with existing healthcare programs, such as TB or noncommunicable disease initiatives, can enhance resource utilization and program scalability. Implementing lung cancer screening in resource-limited settings requires strategic investment, capacity building, and policy interventions that prioritize equity. Addressing financial constraints, infrastructure gaps, and sociocultural barriers can help overcome existing challenges. By focusing on cost-effective strategies, public awareness, and risk-based eligibility criteria, global efforts can promote equitable access to lung cancer screening and improve outcomes.
Lastly, as part of the medical community, we play an important role in a patient's decision to pursue lung cancer screening. Being up to date with current lung cancer screening recommendations, identifying eligible patients, and encouraging a patient to undergo screening often is the difference-maker. Electronic medical record (EMR) systems and reminders are helpful in this regard, but relationship building and a recommendation from a trusted provider are really essential here.
Dr. Nate Pennell: I think that makes a lot of sense. I mean, there are technology improvements. For example, our lung cancer screening program at The Cleveland Clinic, a few years back, we finally started an automated best practice alert in our EMR for patients who met the age and smoking requirements, and it led to a six-fold increase in people referred for screening. But at the same time, there's a difference between just getting this alert and putting in an order for lung cancer screening and actually getting those patients to go and actually do the screening and then follow up on it. And that, of course, requires having that relationship and discussion with the patient so that they trust that you have their best interests.
Dr. Cheryl Czerlanis: Exactly. I think that's important. You know, certainly, while technology can aid in bringing patients in, there really is no substitute for trust-building and a personal relationship with a provider.
Dr. Nate Pennell: I know that there are probably multiple examples within the U.S. where health systems or programs have put together, I would say, quality improvement projects to try to increase lung cancer screening and working with their community. There's one in particular that you discuss in your paper called the "End Lung Cancer Now" initiative. I wonder if you could take us through that.
Dr. Cheryl Czerlanis: Absolutely. "End Lung Cancer Now" is an initiative at the Indiana University Simon Comprehensive Cancer Center that has the vision to end suffering and death from lung cancer in Indiana through education and community empowerment. We discuss this as a paradigm for how community engagement is important in building and scaling a lung cancer screening program.
In 2023, the "End Lung Cancer Now" team decided to focus its efforts on scaling and transforming lung cancer screening rates in Indiana. They developed a task force with 26 experts in various fields, including radiology, pulmonary medicine, thoracic surgery, public health, and advocacy groups. The result of this work is an 85-page blueprint with key recommendations that any system and community can use to scale lung cancer screening efforts. After building strong infrastructure for lung cancer screening at Indiana University, they sought to understand what the priorities, resources, and challenges in their communities were. To do this, they forged strong partnerships with both local and national organizations, including the American Lung Association, American Cancer Society, and others. In the first year, they actually tripled the number of screening low-dose CTs performed in their academic center and saw a 40% increase system-wide. One thing that I think is the most striking is that through their community outreach, they learned that most people prefer to get medical care close to home within their own communities. Establishing a way to support the local infrastructure to provide care became far more important than recruiting patients to their larger system.
In exciting news, "End Lung Cancer Now" has partnered with the IU Simon Comprehensive Cancer Center and IU Health to launch Indiana's first and only mobile lung screening program in March of 2025. This mobile program travels around the state to counties where the highest incidence of lung cancer exists and there is limited access to screening. The mobile unit parks at trusted sites within communities and works in partnership, not competition, with local health clinics and facilities to screen high-risk populations.
Dr. Nate Pennell: I think that sounds like a great idea. Screening is such an important thing that it doesn't necessarily have to be owned by any one particular health system for their patients. I think. And I love the idea of bringing the screening to patients where they are. I can speak to working in a regional healthcare system with a main campus in the downtown that patients absolutely hate having to come here from even 30 or 40 minutes away, and they'd much rather get their care locally. So that makes perfect sense.
So, under the current guidelines, there are certainly things that we can do to try to improve capturing the people that meet those. But are those guidelines actually capturing enough patients with lung cancer to make a difference? There certainly are proposals within patient advocacy communities and even other countries where there's a large percentage of non-smokers who perhaps get lung cancer. Can we expand beyond just older, current and heavy smokers to identify at-risk populations who could benefit from screening?
Dr. Cheryl Czerlanis: Yes, I think we can, and it's certainly an active area of research interest. We know that tobacco is the leading cause of lung cancer worldwide. However, other risk factors include secondhand smoke, family history, exposure to environmental carcinogens, and pulmonary diseases like COPD and interstitial lung disease. Despite these known associations, the benefit of lung cancer screening is less well elucidated in never-smokers and those at risk of developing lung cancer because of family history or other risk factors. We know that the eligibility criteria associated with our current screening guidelines focus on age and smoking history and may miss more than 50% of lung cancers. Globally, 10% to 25% of lung cancer cases occur in never-smokers. And in certain parts of the world, like you mentioned, Nate, such as East Asia, many lung cancers are diagnosed in never-smokers, especially in women. Risk-prediction models use specific risk factors for lung cancer to enhance individual selection for screening, although they have historically focused on current or former smokers.
We know that individuals with family members affected by lung cancer have an increased risk of developing the disease. To this end, several large-scale, single-arm prospective studies in Asia have evaluated broadening screening criteria to never-smokers, with or without additional risk factors. One such study, the Taiwan Lung Cancer Screening in Never-Smoker Trial, was a multicenter prospective cohort study at 17 medical centers in Taiwan. The primary outcome of the TALENT trial was lung cancer detection rate. Eligible patients aged 55 to 75 had either never smoked or had a light and remote smoking history. In addition, inclusion required one or more of the following risk factors: family history of lung cancer, passive smoke exposure, history of TB or COPD, a high cooking index, which is a metric that quantifies exposure to cooking fumes, or a history of cooking without ventilation. Participants underwent low-dose CT screening at baseline, then annually for 2 years, and then every 2 years for up to 6 years. The lung cancer detection rate was 2.6%, which was higher than that reported in the NLST and NELSON trials, and most were stage 0 or I cancers. Subsequently, this led to the Taiwan Early Detection Program for Lung Cancer, a national screening program that was launched in 2022, targeting 2 screening populations: individuals with a heavy history of smoking and individuals with a family history of lung cancer.
We really need randomized controlled trials to determine the true rates of overdiagnosis or finding cancers that would not lead to morbidity or mortality in persons who are diagnosed, and to establish whether the high lung detection rates are associated with a decrease in lung cancer-related mortality in these populations. However, the implementation of randomized controlled low-dose CT screening trials in never-smokers has been limited by the need for large sample sizes, lengthy follow-up, and cost.
In another group potentially at higher risk for developing lung cancer, the role of lung cancer screening in individuals who harbor germline pathogenic variants associated with lung cancer also needs to be explored further.
Dr. Nate Pennell: We had this discussion when the first criteria came out because there have always been risk-based calculators for lung cancer that certainly incorporate smoking but other factors as well and have discussion about whether we should be screening people based on their risk and not just based on discrete criteria such as smoking. But of course, the insurance coverage for screening, you have to fit the actual criteria, which is very constrained by age and smoking history. Do you think in the U.S. there's hope for broadening our screening beyond NLST and NELSON criteria?
Dr. Cheryl Czerlanis: I do think at some point there is hope for broadening the criteria beyond smoking history and age, beyond the criteria that we have typically used and that is covered by insurance. I do think it will take some work to perhaps make the prediction models more precise or to really understand who can benefit. We certainly know that there are many patients who develop lung cancer without a history of smoking or without family history, and it would be great if we could diagnose more patients with lung cancer at an earlier stage. I think this will really count on there being some work towards trying to figure out what would be the best population for screening, what risk factors to look for, perhaps using some new technologies that may help us to predict who is at risk for developing lung cancer, and trying to increase the group that we study to try and find these early-stage lung cancers that can be cured.
Dr. Nate Pennell: Part of the reason we, of course, try to enrich our population is screening works better when you have a higher pretest probability of actually having cancer. And part of that also is that our technology is not that great. You know, even in high-risk patients who have CT scans that are positive for a screen, we know that the vast majority of those patients with lung nodules actually don't have lung cancer. And so you have to follow them, you have to use various models to see, you know, what the risk, even in the setting of a positive screen, is of having lung cancer.
So, why don't we talk about some newer tools that we might use to help improve lung cancer screening? And one of the things that everyone is super excited about, of course, is artificial intelligence. Are there AI technologies that are helping out in early detection in lung cancer screening?
Dr. Cheryl Czerlanis: Yes, that's a great question. We know that predicting who's at risk for lung cancer is challenging for the reasons that we talked about, knowing that there are many risk factors beyond smoking and age that are hard to quantify. Artificial intelligence is a tool that can help refine screening criteria and really expand screening access. Machine learning is a form of AI technology that is adept at recognizing patterns in large datasets and then applying the learning to new datasets. Several machine learning models have been developed for risk stratification and early detection of lung cancer on imaging, both with and without blood-based biomarkers. This type of technology is very promising and can serve as a tool that helps to select individuals for screening by predicting who is likely to develop lung cancer in the future.
A group at Massachusetts General Hospital, represented in our group for this paper by my co-authors, Drs. Fintelmann and Chang, developed Sybil, which is an open-access 3D convolutional neural network that predicts an individual's future risk of lung cancer based on the analysis of a single low-dose CT without the need for human annotation or other clinical inputs. Sybil and other machine learning models have tremendous potential for precision lung cancer screening, even, and perhaps especially, in settings where expert image interpretation is unavailable. They could support risk-adapted screening schedules, such as varying the frequency and interval of low-dose CT scans according to individual risk and potentially expand lung cancer screening eligibility beyond age and smoking history. Their group predicts that AI tools like Sybil will play a major role in decoding the complex landscape of lung cancer risk factors, enabling us to extend life-saving lung cancer screening to all who are at risk.
Dr. Nate Pennell: I think that that would certainly be welcome. And as AI is working its way into pretty much every aspect of life, including medical care, I think it's certainly promising that it can improve on our existing technology.
We don't have to spend a lot of time on this because I know it's a little out of scope for what you covered in your paper, but I'm sure our listeners are curious about your thoughts on the use of other types of testing beyond CT screening for detecting lung cancer. I know that there are a number of investigational and even commercially available blood tests, for example, for detection of lung cancer, or even the so-called multi-cancer detection blood tests that are now being offered, although not necessarily being covered by insurance, for multiple types of cancer, but lung cancer being a common cancer is included in that. So, what do you think?
Dr. Cheryl Czerlanis: Yes, like you mentioned, there are novel bioassays such as blood-based biomarker testing that evaluate for DNA, RNA, and circulating tumor cells that are both promising and under active investigation for lung cancer and multi-cancer detection. We know that such biomarker assays may be useful in both identifying lung cancers but also in identifying patients with a high-risk result who should undergo lung cancer screening by conventional methods.
Dr. Nate Pennell: Anything that will improve on our rate of screening, I think, will be welcome. I think probably in the future, it will be some combination of better risk prediction and better interpretation of screening results, whether those be imaging or some combination of imaging and biomarkers, breath-based, blood-based. There's so much going on that it is pretty exciting, but we're still going to have to overcome the stigma and lack of public support for lung cancer screening if we're going to move the needle.
Dr. Cheryl Czerlanis: Yes, I think moving the needle is so important because we know lung cancer is still a very morbid disease, and our ability to cure patients is not where we would like it to be. But I do believe there's hope. There are a lot of motivated individuals and groups who are passionate about lung cancer screening, like myself and my co-authors, and we're just happy to be able to share some ways that we can overcome the challenges and really try and make an impact in the lives of our patients.
Dr. Nate Pennell: Well, thank you, Dr. Czerlanis, for joining me on the By the Book Podcast today and for all of your work to advance care for patients with lung cancer.
Dr. Cheryl Czerlanis: Thank you, Dr. Pennell. It's such a pleasure to be with you today. Thank you.
Dr. Nate Pennell: And thank you to our listeners for joining us today. You'll find a link to Dr. Czerlanis' article in the transcript of this episode.
Please join us again next month for By the Book's next episode and more insightful views on topics you'll be hearing at the education sessions from ASCO meetings throughout the year, and our deep dives on approaches that are shaping modern oncology.
Disclaimer:
The purpose of this podcast is to educate and to inform. This is not a substitute for professional medical care and is not intended for use in the diagnosis or treatment of individual conditions. Guests on this podcast express their own opinions, experience, and conclusions. Guest statements on the podcast do not express the opinions of ASCO. The mention of any product, service, organization, activity, or therapy should not be construed as an ASCO endorsement.
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Disclosures:
Dr. Nate Pennell:
Consulting or Advisory Role: AstraZeneca, Lilly, Cota Healthcare, Merck, Bristol-Myers Squibb, Genentech, Amgen, G1 Therapeutics, Pfizer, Boehringer Ingelheim, Viosera, Xencor, Mirati Therapeutics, Janssen Oncology, Sanofi/Regeneron
Research Funding (Institution): Genentech, AstraZeneca, Merck, Loxo, Altor BioScience, Spectrum Pharmaceuticals, Bristol-Myers Squibb, Jounce Therapeutics, Mirati Therapeutics, Heat Biologics, WindMIL, Sanofi
Dr. Cheryl Czerlanis:
Research Funding (Institution): LungLife AI, AstraZeneca, Summit Therapeutics
