Lung Cancer Prevention and Screening

Virginia Moyer, MD, MPH

Today we are discussing lung cancer prevention and screening with Virginia Moyer, MD, MPH. Dr. Moyer is the chair of the US Preventive Services Task Force, which is an independent panel of clinical experts who provide recommendations in prevention and evidence-based medicine. Dr. Moyer’s expertise is in diagnostics, evidence-based medicine, and health service research. The Task Force reviews scientific evidence on screening and prevention and develops evidence-based recommendations for primary care clinicians in the United States.

-Interviewed by Anna Azvolinsky, PhD

Cancer Network: Dr. Moyer, January marks the 50th anniversary of the 1964 Surgeon General’s Report that linked smoking to diseases such as lung cancer and heart disease. What do we know about how smoking cessation is promoted by clinicians, and what can be done to get more patients to quit smoking?

Dr. Moyer: That is a good question. The Task Force recognizes that the best way to prevent diseases such as lung cancer and heart disease, and unfortunately, many other diseases, is to promote smoking cessation, or actually, preventing people from smoking in the first place. People who quit smoking substantially reduce their risk of developing and dying from lung cancer, and their risk continues to go down over time. The Task Force is in the early stages of updating its recommendation on counseling interventions to prevent tobacco use and tobacco-caused diseases in adults and pregnant women. In our 2009 recommendations, we recommended that clinicians ask all adults about tobacco use and provide tobacco cessation interventions for those who do use tobacco products, and also that clinicians ask pregnant women about tobacco use and provide augmented pregnancy-tailored counseling for pregnant women who smoke.

Cancer Network: The Task Force recently updated their lung cancer screening guidelines. Can you give us an update on what is new in these updated recommendations?

Dr. Moyer: If we are unsuccessful in keeping people from smoking, then unfortunately, we are going to have to deal with lung cancer. In 2004 the Task Force determined that there was not enough evidence to recommend for or against screening in adults who had no signs or symptoms of lung cancer. But since that time there have been new studies conducted that have provided evidence on the benefits of screening heavy smokers for lung cancer. That evidence shows that using low-dose CT scans to screen for lung cancer every year in individuals at high risk substantially reduces deaths from lung cancer.

Cancer Network: What do you think is the potential impact of the new recommendations on screening rates in the United States?

Dr. Moyer: The potential impact is that, at this point, it would depend on whether everyone did what the Task Force recommends. So, it is a little bit hard to tell the number of people who would be screened as we have to make a lot of assumptions. But right now we estimate that there are around 10 million people in the United States who are current smokers between the ages of 55 and 80 who have a 30 pack-year or greater history of smoking-a 30 pack-year is one pack per day for 30 years or two packs per day for 15 years. Or there are those who have a 30 pack-year history and have quit for less than 15 years. However, many of the people who would fall into that category may actually not be good candidates for screening because of other health conditions that may keep them from actually being treated. Treatment generally involves surgery, so someone who has major other illness or whose expected lifespan is quite short would actually not benefit from screening because they couldn’t be treated. Right now, about 160,000 people die from lung cancer each year in this country. Our estimate is that if the recommendations were fully implemented, it may save as many as 20,000 lives each year. That is a lot of lives, but unfortunately, it is not even a quarter of those who currently die from lung cancer.

Cancer Network: What do the guidelines say about screening for those who do not have a history of smoking but may have a history of lung cancer in their family?

Dr. Moyer: The guidelines did not address anything except for screening smokers, and we only recommend screening for those with a quite heavy smoking history, but like I said, that is a lot of people.

Cancer Network: What are the major hurdles for lung cancer screening that you see or that the Task Force anticipates in the next few years?

Dr. Moyer: Well, there are a number of those. For one thing, there are certainly going to be many patients who don’t meet the criteria of high risk but are concerned about the possibility of lung cancer. Unfortunately, we don’t have evidence right now on whether expanding low-dose CT scanning to screen lower-risk patients has more benefits than harms. It is really important that clinicians talk to their lower-risk patients about potential harms of screening. In the future we hope that there will be better risk-assessment tools to help us identify individual patient risk and to enable us to tailor a little bit better than just an age range and a smoking history. In the meantime, clinicians should speak with their patients on the importance of quitting smoking because the bottom line is that smoking causes 85% of lung cancers in the United States, and those who quit smoking substantially reduce their risk of developing lung cancer and dying from lung cancer, and their risk goes down over time. Once you have quit for 15 years, you are not even in a high-risk category anymore. Every screening has the potential to be both beneficial and harmful. Screening only works when the benefits outweigh the harms. Lung cancer screening can result in false-positives, which can lead to unnecessary biopsies and surgery; and the radiation you get during low-dose CT scans is also potentially harmful because you actually have significant exposure over time in some who are otherwise healthy. But, for people who are at high risk, the harms are outweighed by the benefits and they should be screened. For people not at high risk, the balance may not be so favorable.

Cancer Network: Are there any new screening techniques besides CT scans that are either in development or are already available?

Dr. Moyer: Available, no. There are certainly many things in development. We used to think we could screen with just chest X-rays and that was proven to be completely unworkable. It just doesn’t give you the information you need. The low-dose CT scanning seems to work better but it is far, far from perfect. There are other things in the works, including some biologic tests and things like that that researchers are looking at, but none of them have been proven to work yet or are ready for prime time. But because of what we have currently, we know we can do something. But I think we can do it better. There is a lot of research going on to see how we can improve this.

Cancer Network: Thank you so much for joining us today, Dr. Moyer.

Dr. Moyer: I’m delighted.