Death Rates for Smokers Are Not Improved Despite Early Diagnosis
Tampa, FL – The first report of an international study looking at computed tomography (CT) to screen current or former smokers for lung cancer found that screening did not reduce deaths from lung cancer. Although CT screening found nearly three times as many lung cancers as predicted, the researchers found that early detection and treatment did not lead to a corresponding decrease in advanced lung cancers or a reduction in deaths from lung cancer. H. Lee Moffitt Cancer Center & Research Institute’s Dr. Melvyn Tockman co-authored the study led by researchers at Memorial Sloan-Kettering Cancer Center. The study found no advantage to using CT screening on current or former smokers -- thepopulation at highest risk for developing lung cancer. The findings appear in the March 7 issue of the Journal of the American Medical Association.
“Our data have not yet shown that helical CT screening for lung cancer is beneficial to patients,” said Tockman, a member of Moffitt’s thoracic oncology program. “Until there is beneficial evidence of lung cancer mortality reduction that outweighs the potential harm from additional surgery and radiation, helical CT screening should continue to be considered a research procedure.”
Beginning in 1998, 3246 asymptomatic men and women with a median age of 60 who had smoked or still smoked for an average of 39 years were screened for lung cancer with state-of-the-art multi-detector CT at Moffitt, the Mayo Clinic in Minnesota, or the Instituto Tumori in Italy. Each study provided an initial CT scan and then at least three subsequent annual exams. The researchers followed the volunteers to see how many had cancers detected by screening and how many had surgery to remove them. They then used government death records to follow the study participants for five years to see if they died of lung cancer. The researchers compared what they saw to what statistical models predicted would happen without screening.
Over the course of the studies, screening found more than three times as many lung cancers as the number that would have been diagnosed without screening, and there were ten times as many surgeries performed for lung cancer compared to what was expected. This meant that as a direct result of the test, an additional 99 people were diagnosed with lung cancer and an additional 98 had lung surgery. However, the early detection and treatment did not change the death rate. There were 38 deaths due to lung cancer, and 39 would have occurred without screening.
CT screening is not without risk. The radiation can become significant when the scans are repeated every year. Because the test is not very specific, it is known to have false positive results, which can lead to additional CT scans at full radiation doses and invasive procedures like lung biopsies. This study also suggests CT screening can lead to additional major surgeries to remove very small growths that look like lung cancer but do not pose a meaningful threat to the patient’s health.
The study was led by Dr. Peter B. Bach and co-authored by Dr. James R. Jett from Memorial Sloan-Kettering, Dr. Steven J. Swensen of the Mayo Clinic and Dr. Ugo Pastorino of the Instituto Tumori. It was supported by grants from the European Institute of Health, the Italian Ministry of Health, the National Cancer Institute, the Department of Defense, and funds from the four involved institutions.
About H. Lee Moffitt Cancer Center & Research Institute
Located in Tampa, Florida on the University of South Florida campus, H. Lee Moffitt Cancer Center & Research Institute (www.moffitt.org) is the only Florida-based cancer center with the NCI designation as a Comprehensive Cancer Center for its excellence in research and contributions to clinical trials, prevention and cancer control. Moffitt currently has 15 affiliates in Florida, one in Georgia and two in Puerto Rico. Additionally, Moffitt is a member of the National Comprehensive Cancer Network, a prestigious alliance of the country’s leading cancer centers, and is listed in U.S. News & World Report as one of America’s Best Hospitals for cancer. Moffitt’s sole mission is to contribute to the prevention and cure of cancer.