Lung Cancer Screening Guideline: Frequently Asked QuestionsJan 11, 2013
Didn’t the ACS already release guidance about lung cancer screening using CT scans?
After the release of the National Lung Screening Trial (NLST) results in late 2010, the American Cancer Society issued interim guidance for clinicians and adults at risk for lung cancer while a full guideline was being developed. The interim guidance was designed to give clinicians and the public guidance quickly, since lung screening was being promoted based on results of the NLST. The full guideline process required time to review the evidence related to the target population, the screening protocol, and the benefits, limitations, and harms associated with testing.
What do the recommendations say?
The guidelines recommend that:
- Clinicians who have access to high-volume, high-quality lung cancer screening and treatment centers should talk about screening to their healthy patients aged 55 years to 74 years who have at least a 30–pack-year smoking history and who currently smoke or have quit within the past 15 years.
- Clinicians should discuss with their patients the potential benefits, limitations, and harms associated with screening for lung cancer with low-dose computed tomography (LDCT) and together the clinician and patient should decide what is best for the patient. Clinicians should not discuss lung cancer screening with low dose CT with patients who do not meet the above criteria.
- Adults who choose to be screened should receive yearly LDCT screening until they reach age 74 years.
- A chest X-ray should not be used for cancer screening.
- Wherever possible, adults who choose to undergo lung screening should enter an organized screening program at an institution with expertise in LDCT screening, with access to a multidisciplinary team skilled in the evaluation, diagnosis, and treatment of abnormal lung lesions. If such a program is not accessible, but the patient strongly wishes to be screened, they should be referred to a center that performs a reasonably high volume of lung CT scans, diagnostic tests, and lung cancer surgeries.
- Current smokers should be informed of their continuing risk of lung cancer, and referred to smoking cessation programs. Screening should not be viewed as an alternative to smoking cessation.
Why do these guidelines recommend a discussion about screening, and not simply that people get tested?
The guidelines are consistent with a broad move towards shared decision-making in screening, which is designed to insure that patients are fully informed about the benefits, limitations, and the potential adverse events of screening. Risks include false positive findings, which may involve follow-up testing that could be invasive, and some anxiety. At this time, lung cancer screening with low dose CT is fairly new compared with screening tests for other cancers that are in common use. Cost may also be an issue. For these reasons, it is important that adults eligible for screening have this discussion about what to expect from testing.
So someone who elects not to be screened would still be following your guidelines?
Yes. Some people may be willing to accept the risks and costs associated with having a low dose CT screening every year for its potential benefit of reducing their risk of dying from lung cancer. Some individuals may be willing to have further tests, even tests that have a rare but real risk of complications and death. Other people may place greater value on avoiding testing that carries a high risk of false-positive results and a small risk of complications. Of course, an individual who meets the criteria and chooses not to undergo screening may revisit the option for testing in the future.
Do other groups have lung cancer screening recommendations?
Other organizations have issued lung cancer screening guidelines, and they are very similar to those from the American Cancer Society. They include the American College of Chest Physicians, the American Society of Clinical Oncology, the American Lung Association, the National Comprehensive Cancer Network, and the American Association for Thoracic Surgery.
Why doesn’t the American Cancer Society recommend screening for non-smokers?
We simply do not have the evidence yet to show that CT scans will be beneficial in healthy adults who never smoked, or current or former smokers with fewer pack-years of smoking. The current evidence was based on studies involving smokers with specific smoking histories.
The evidence review found eight randomized clinical trials looking at low dose CT screening, all of which studied populations who smoked, who are known to be at significantly higher risk of lung cancer. The lowest minimum exposure in these trials was 15 pack-years, but more commonly was 20+ or 30+ pack-years. In five of those studies, the maximum allowable years since smoking cessation was 10 years, and in two studies it was 15 years. In developing this guideline, particular weight was given to the NLST results based on its larger study size. It studied men and women aged 55 years to 74 years in reasonably good health with 30 or more pack-years of smoking who were either current smokers or who quit within the past 15 years.
Why not screen younger smokers using CT?
At this time, researchers are focused on determining if screening should be offered to younger smokers with greater lifetime exposure to cigarette smoke. For screening to be effective, the screened population should be at or above a certain level of risk. While younger, current smokers are at risk for developing lung cancer in the future, the incidence of lung cancer is low in this age group. Screening in this group would likely pose more harm and less benefit than it would in the older population in which screening has been shown to be effective. Of greatest importance is that these adults stop smoking, which would reduce their risk of developing lung cancer in the future.
What are the downsides of screening?
While the direct harms of screening, most notably radiation exposure, are small, there are other harms associated with low dose CT screening. They include issues like anxiety associated with abnormal testing results, additional imaging tests and biopsy procedures associated with false-positive results, and the need to investigate incidental findings on LDCT outside of the lung field. There can also be serious harms. In rare instances, diagnostic evaluations (such as lung biopsy) in patients with and without lung cancer can lead to hospitalizations and death.
Can we know for sure how many lives screening will save?
No. Even though there is strong evidence supporting the value of screening for lung cancer with low dose CT in this high risk population, we don’t yet know how effective community based screening for lung cancer with low dose CT will be. We don’t yet know if it will exceed or fail to achieve the benefit that has been observed in the controlled clinical studies that have been done.
Will insurance pay for my scan?
We are not able to answer this question. At this time some insurance carriers are covering lung cancer screening, while others have not yet made this decision. The American Cancer Society has encouraged health plans to cover lung cancer screening in those who meet the criteria outlined in this recommendation. In general, if there is good supporting evidence for screening, and in this case there is, and if you and your doctor determine that you meet the eligibility criteria and reach an informed decision to undergo screening, then it is likely that some coverage will be available. However, it is best to check with your insurance carrier in advance.
Is this the final word on screening?
No. Additional scientific reports from the NLST, the European clinical trials, and evidence from observational studies will contribute to and fill in the existing knowledge gaps. As with other guidelines for cancer screening, we can expect that this initial guideline will be revised as new data become available.
What concerns are there about how we proceed with screening among the millions of Americans who are eligible?
It is important that the implementation of lung cancer screening occurs in a manner that is focused on maximizing benefits and minimizing harms. At this time, there is sufficient evidence to support screening in the high risk populations outlined in this guideline, provided that the patient has undergone a thorough discussion of the benefits, limitations, and risks, and can be screened in a setting with experience in lung cancer screening. Many questions remain to be answered, and an experience base and infrastructure to support population-based lung cancer screening is not yet in place and needs to be built.