Lung Cancer Screening Saves Lives
November is Lung Cancer Awareness month, and one of the most important messages we can share is the potential for lung cancer screening to save lives. Over 160,000 people die each year from lung cancer - a number that could be greatly decreased by the widespread adoption of low dose helical CT scans for early detection.
Last year, one of the most pivotal studies in lung cancer research, the National Lung Screening Trial, demonstrated that low-dose helical CT scans can lower mortality from lung cancer by at least 20%. Since then, the National Comprehensive Cancer Network has recommended that individuals at high risk for lung cancer be screened regularly.
UALC spoke with UALC medical committee member Dr. Steven Dubinett of the University of California, Los Angeles, about the results of the trial last year, and the information is just as vital and timely as ever. Read a recap of our discussion here:
UALC: Can you give us an overview of the study and what was found?
Dr. Dubinett: The purpose of the study was to determine if screening with CT scans could benefit overall mortality for lung cancer, meaning reducing the number of deaths due to lung cancer. The National Cancer Institute and the American College of Radiology Imaging Network enrolled more than 53,000 men and women at more that 30 different trial sites during a 20-month period with follow-up. The trial participants were at high risk for lung cancer, meaning they were either current or former heavy smokers between the ages of 55-74.
The results showed a 20% reduction in mortality, meaning 20% fewer deaths from lung cancer in the study group that had annual CT screening compared to the group given annual chest X-rays.
This is a very important study, the first study in lung cancer to have this dramatic impact on mortality from the disease. This result is likely to be the finding of the decade in terms of its importance to people at risk for lung cancer. I think we should take it very seriously, but we need to be careful about how we translate these findings to people who fall outside the study group in terms of age or smoking history.
UALC: What about younger patients, or patients who are never-smokers?
Dr. Dubinett: It’s difficult to translate these results to patients with a different background. This was directed at a specific group of individuals, ages 55-74 with a smoking history of at least 30 pack years (meaning one pack a day for 30 years, or two packs a day for 15 years). There are risks and benefits to every test that’s performed, and you want to make sure that the test will be a good screening tool according to each patient. In this case, we know CT scans are useful for this particular group of people at risk. Outside of that specific smoking history and age group, it’s not yet clear what the impact will be.
UALC: Participants received annual CT scans or chest X-rays. Does this study answer the question about whether chest X-rays are useful screening tools?
Dr. Dubinett: Before we can answer any questions about whether chest x-rays are useful, we have to wait for the full study results to be published in 2011. The fact that the NCI made this public before the full study results are released meant that they felt confident that the primary endpoint (the number of deaths in the participants who had CT scans) was very significant and a major finding relevant to public health. They took the unusual step of releasing the information early so individuals could discuss with their doctors whether CT scanning might be the correct choice for their treatment.
UALC: There have been a number of concerns about CT scans as diagnostic tools for lung cancer – what about false positives?
Dr. Dubinett: As many as 25% of people who received CT screening had abnormalities detected on the CT scans that did not appear to be lung cancer. We’ll need to wait and see what’s in the final report to know the full implications. It does raise the concern that there will be a large number of people who will need additional tests, and some of those additional tests could be invasive procedures such as biopsies. Additional research into developing non-invasive tests, such as blood tests, is needed to help physicians and patients make decisions about what should be done about those indeterminate scans. There is an important gap to be filled with new research: to help develop new non-invasive tests that will make imaging even more useful.
UALC: What about radiation exposure?
Dr. Dubinett: This study really wasn’t designed to address the effects of radiation exposure. That takes many more patients, and many more years of follow-up. It is important to note that the screening CT dose is not as high as the diagnostic CT dose. Screening CT scans are low dose and fall into a different category. People may be confused about this, and it’s important to know that the information that’s been out in the newspapers recently about radiation overdoses due to diagnostic CT scans is really a different topic.
UALC: Should patients be requesting CT scans as part of their regular care?
Dr. Dubinett: I think at this point each individual needs to discuss this with their personal physician. Following the publication of the study next year, guideline recommendations will be made by professional groups to physicians, insurance companies, and the government. I think it’s highly likely that there will screening recommendations for this particular group of high-risk individuals.
UALC: It all comes down to identifying risk factors – in this case age and a history of heavy smoking.
Dr. Dubinett: Right, there is ongoing research now into other risk factors and biomarkers for lung cancer. For example, what are the genetic risks we need to look out for, what elements of family history are applicable, and what other kinds of exposures may either increase risk from smoking or lead to lung cancer in non-smokers?
The primary finding of this study is an extremely optimistic one. We had not previously known that we could help people with lung cancer through early detection. This gives great momentum for not only this kind of imaging test, but also for further research into tests that could come before a CT scan. We would like to determine risk for lung cancer through a blood test or by taking a brushing from someone’s mouth to determine whether someone should have a CT scan or be observed more closely. This opens up the field to be even more sophisticated and have a greater impact for individuals at risk, both smokers and non-smokers.
Read more about the National Lung Screening Trial from the National Cancer Institute, and download Uniting Against Lung Cancer's Fact Sheets on Lung Cancer Screening here.