From the transcript of a video by Dr. Mark G. Kris, MD, Chief, Thoracic Oncology, Memorial Sloan-Kettering Cancer Center, published in MedscapeRadiology [Registration required. Free] speaking on the recent announcement by the National Cancer Institute about the release of data from the National Lung Screening Trial [Abstract & link below].
…we have never had a screening test for lung cancer that met the gold standard for a successful screening test (ie, a test that is able to prove that the deaths due to lung cancer in a population of patients were decreased by screening). The data released … in the National Lung Screening Trial, which included over 53,000 patients randomized to receive 3 yearly chest x-rays or 3 yearly low-dose CT scans, there was a 20% decrease in mortality from lung cancer. It’s simply an amazing result with an immediate impact on this disease. One thing we have been fighting to do, as control of other cancers has improved, is to improve the control of lung cancer and cut down the death rate like the death rate has been cut down in prostate, breast, and colorectal cancer.
Finally we have a screening test that meets that gold standard and has a substantial opportunity to decrease the death rate for lung cancer. In the group that was screened, all patients had smoked 30 pack years, which is the equivalent of 1 pack per day for 30 years, 2 packs per day for 15 years, and so on. The technique used was a standard helical CT using a low-dose radiation technique. This type of scan is available anywhere.
Based on these data, it makes sense to recommend screening with a low-dose helical CT for any person who has smoked 30 pack years. This is a very substantial change; again, we’ve had no recommended screening for lung cancer. Another interesting piece of data is that all-cause mortality for the screened group was actually 7% less in the group that had the CT compared with those that had a chest x-ray. I think people are concerned that the x-rays themselves could lead to some sort of cancer risk, but that clearly was not borne out of this trial.
I think you’re going to see a lot of discussion about this trial. It’s appearing on the front page of at least my hometown newspaper. I urge you to read the information carefully, look at the specifics of the trial as they come out in the next few weeks, and also think about which patients in your practice and which patients who you see would meet these screening criteria. It’s going to change how we do business and it’s going to put a tremendous burden on our systems, but I think it is worth assuming as it means fewer deaths from lung cancer — something we have only hoped to achieve.
Many people have been supporting this. Many people, myself included, have been waiting for this result. Now that it’s out, there is, in my estimation, no reason to wait another day to begin screening.
The National Lung Screening Trial: Overview and Study Design, published online in Radiology before print.
The National Lung Screening Trial (NLST) is a randomized multicenter study comparing low-dose helical computed tomography (CT) with chest radiography in the screening of older current and former heavy smokers for early detection of lung cancer, which is the leading cause of cancer-related death in the United States. Five-year survival rates approach 70% with surgical resection of stage IA disease; however, more than 75% of individuals have incurable locally advanced or metastatic disease, the latter having a 5-year survival of less than 5%. It is plausible that treatment should be more effective and the likelihood of death decreased if asymptomatic lung cancer is detected through screening early enough in its preclinical phase. For these reasons, there is intense interest and intuitive appeal in lung cancer screening with low-dose CT. The use of survival as the determinant of screening effectiveness is, however, confounded by the well-described biases of lead time, length, and overdiagnosis. Despite previous attempts, no test has been shown to reduce lung cancer mortality, an endpoint that circumvents screening biases and provides a definitive measure of benefit when assessed in a randomized controlled trial that enables comparison of mortality rates between screened individuals and a control group that does not undergo the screening intervention of interest. The NLST is such a trial. The rationale for and design of the NLST are presented.
Full text available here [Free]