Lung cancer is the No. 1 cancer killer in the United States, with 222,520 people expected to die from it this year. In part, this is because there has been no reliable way to detect lung cancer in its earliest, most treatable stage. Now, new research suggests a way to screen people at high risk for lung cancer and reduce the number of deaths from this disease.
The National Lung Screening Trial provides the first evidence that lung screening can reduce cancer deaths. What does this mean for someone concerned about lung cancer? Experts from the University of Michigan Comprehensive Cancer Center explain.What is the National Lung Screening Trial?
The National Lung Screening Trial began in 2002 and enrolled more than 53,000 participants who were current or former heavy smokers, ages 55 to 74. The trial randomly assigned people to receive lung screening either by low-dose helical CT scans or chest X-rays. The trial was sponsored by the National Cancer Institute, and the University of Michigan was one of 33 places across the country to take part. U-M enrolled 850 participants.What were the results of the trial?
The trial found 20% fewer lung cancer deaths among those participants screened with low-dose helical CT compared to those screened with chest X-ray. A secondary finding, which was not the main goal of the trial, showed that deaths from all causes, including lung cancer, were 7% lower in the CT-screened group. The study looked specifically at people at high risk for lung cancer based on smoking history and age. The results should not be generalized to everybody. Initial results of the study were released in November 2010, and the full study was published June 29, 2011 in the New England Journal of Medicine.What is U-M's response to this study?
Lung cancer specialists at U-M are very excited about these findings. We are currently discussing options around a lung screening program for people at high risk for lung cancer. Any program would include smoking cessation, which was also part of the NLST, as quitting smoking is the single best way to reduce lung cancer risk.What is a helical CT scan?
Low-dose helical CT, also called spiral CT, uses X-rays to scan the entire chest in about 5 to 10 seconds during a single breath-hold. The CT scanner looks like a donut, with the person undergoing a CT scan lying still on a table that moves through the opening in the scanner as the CT machinery rotates around the person. A computer creates images from the X-ray information coming from the scanner and then assembles these images into a series of two-dimensional slices of the lung at very small intervals to provide excellent detail and enable the detection of very small lesions, referred to as nodules, that are often smaller than 1 centimeter. Nearly all hospitals and free-standing radiology facilities in the United States have a helical CT machine. These are routinely used after cancer is diagnosed to determine how advanced it is.What are the risks of lung screening?
Risks include:- Too many false-positives:
In other words, something shows up on the test, but turns out not to be cancer. - Physical harm from additional testing or surgery to evaluate the abnormal findings.
For example, lung biopsies can lead to partial collapse of the lung, bleeding, infection, pain and discomfort. - Exposure to radiation:
The helical CT scans used for lung cancer screening use a very small amount of radiation, less than used for most CT scans. The annual exposure from screening adds up over years. The cumulative effect of radiation exposure is not known, but for those at high risk for lung cancer, the risk from the low level of radiation exposure from screening is not felt to be a significant. - Cost-effectiveness:
There must be a direct benefit of saving lives in order to justify the cost of screening. In the case of lung screening, we don't yet know the real cost of saving lives. This data is expected to be reported as the NLST data are further analyzed. It will be important to carry out screening in a way that society can afford.
Who should be screened for lung cancer?
The study looked at former or current smokers ages 55-74 who have smoked the equivalent of 1 pack of cigarettes a day for 30 years or more. This group is considered at high risk for lung cancer. That doesn't mean they are the only people who might develop lung cancer, and it doesn't mean everyone in this group will develop lung cancer. Because this is the group the study focused on, any screening guidelines likely will be limited to this group.Why can't everyone be screened?
There are risks associated with lung screening. Up to half of patients undergoing a screening lung CT scan may have a lung nodule found. When a nodule is found, patients must undergo additional testing to determine if it is cancerous or benign. These additional tests can include more imaging with radiation exposure or even surgery to remove the nodule. The vast majority of nodules that are identified - more than 98% to 99% -- turn out not to be cancer. This means people may needlessly face physical harm or discomfort, worry and expense.Lung screening is expensive. Screening everyone for lung cancer would add a tremendous burden to the health care system, including federal and state governments who fund Medicare and Medicaid programs.
At this time, there is no evidence to support screening people who have not been heavy smokers or those who have been exposed to second-hand smoke. Scientists are trying to find biomarkers or other indicators to help determine who is most at risk of developing lung cancer. In the meantime, the best evidence we have limits possible screening recommendations to older adults who have been heavy smokers.
Can I start getting lung screenings?
Because the NLST data was just released, national agencies that set guidelines and policy still have to meet to determine their recommendations. These recommendations will affect whether Medicare and private insurance companies will cover lung screenings, how often and for whom. Currently, lung cancer CT screening is not covered by insurance.UMHS offers lung cancer screening using low radiation exposure techniques at our state of the art CT facilities in Ann Arbor, Canton and Livonia. All CTs are read by board certified radiologists with special training in radiology of the lungs. Many of these radiologist were readers in the NLST.
At this time, most insurance plans do not cover CT for lung cancer screening. UMHS offers the test for $365.
To obtain a lung cancer screening CT, please contact the Radiology Call Center at 734-936-4500, between 8 a.m. and 5 p.m., Monday through Friday. A physician's order is required. You can download a copy of our radiology requisition form [PDF]. We do not accept direct patient referrals. To understand the risks and benefits of lung cancer screening, we recommend you discuss this with your physician.
