On Cancer: Pulmonary Specialist Peter Bach Discusses New Findings on Benefits of CT Screening for Lung Cancer

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CT Screening of People at Very High Risk for Lung Cancer

Memorial Sloan-Kettering’s Peter Bach, an epidemiologist and a pulmonary and critical care physician, discusses new findings that CT screening of high-risk people may detect lung cancer earlier and improve the effectiveness of treatment.

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For several decades, physicians and researchers have been investigating methods of screening people for lung cancer, the leading cause of cancer deaths. Now, a group of researchers and medical societies led by epidemiologist and pulmonary and critical care physician Peter Bach has found that computed tomography (CT) screening may prevent one in five cancer deaths for people at a very high risk of developing lung cancer.

Dr. Bach, who directs Memorial Sloan-Kettering’s Center for Health Policy and Outcomes, and colleagues reviewed and summarized years of studies on lung cancer CT screening. Their findings, which appeared online on May 20 in The Journal of the American Medical Association, also led to the publication of new screening guidelines by the American College of Chest Physicians and the American Society for Clinical Oncology.

In a recent interview, Dr. Bach discussed the study results and the clinical recommendations.

What do this research and the new guidelines indicate about the benefits of CT screening for lung cancer?

By the time we diagnose most people with lung cancer today, the disease is in advanced stages, cannot be removed through surgery, and is difficult to cure. Because of this, researchers and members of the American Cancer Society, the National Comprehensive Cancer Network, the American College of Chest Physicians, and the American Society for Clinical Oncology came together to evaluate years of data about lung cancer screening.

We now have enough evidence and high-quality research to suggest that there is a small group of people who are at a very high risk for lung cancer who may benefit from annual CT screening for three years in a row. This type of screening can sometimes detect cancers at early stages, when treatment may be more effective.

What types of people might benefit from lung CT screening?

People in a specific group are at a very high risk for lung cancer. They must be 55 to 74 years old. They must have smoked 30 pack years, which is calculated by multiplying the number of years they have smoked by the number of packs per day – which could be a pack per day for 30 years. This group includes current smokers as well as former smokers who have quit within the past 15 years.

We estimate that about eight million Americans may fall into this category. The people who do not fall into this group have a much lower chance of developing lung cancer, so screening might do more harm than good.

What is the take-home message for people who are at a very high risk for lung cancer?

If you do fall into this group, it's worth considering being screened and discussing it with your doctor. However, we must be careful to balance the potential benefits with the risks of radiation exposure or over-treatment that could result from screening. We have to be effective at differentiating risky findings on CT scans from findings that can be safely watched for a period of time, and do not require invasive follow-up procedures.

Are there any other important factors that people should keep in mind when considering lung cancer screening?

The study that showed a benefit for lung cancer CT screening was conducted primarily at large centers that have many physicians who specialize in thoracic or lung diseases. We don’t have any evidence that the CT scanning approach will work in other settings.

There are still questions about how to most effectively accomplish screening while reducing any harms of over-diagnosis or over-treatment, but these are the first results to show that there may be a benefit to screening certain people.