There are a large number of former smokers who may be diagnosed with lung cancer only in the late stages of the disease since they do not qualify for early detection lung cancer screening, according to research conducted at the Mayo Clinic. The scientists behind the study “Trends in the Proportion of Patients With Lung Cancer Meeting Screening Criteria” criticize the screening criteria and call attention to policymakers in an article published in the journal of the American Medical Association, JAMA.
The Mayo Clinic study highlights the fact that older patients who smoke while younger are still at risk of developing the disease, but do not meet the CT scan screening criteria established by the U.S. Preventive Services Task Force. Currently the criteria, used by physicians and insurance companies, only recommends the examination for asymptomatic adults between 55 and 80 years old that smoked at least a pack of cigarettes per day over 30 years, and are either still smoking or have quit during the last 15 years.
“As smokers quit earlier and stay off cigarettes longer, fewer are eligible for CT screening, which has been proven effective in saving lives,” said an epidemiologist at the Mayo Clinic Cancer Center, Ping Yang, MD, PhD. “Patients who do eventually develop lung cancer are diagnosed at a later stage when treatment can no longer result in a cure.The existing screening program will become less effective at reducing lung cancer mortality in the general population, if they continue to use the same criteria.”
The researchers conducted a retrospective analysis of data regarding 140,000 smokers in Olmsted County, Minnesota who were 20 years or older between 1984 and 2011. They also studied the proportion of lung cancer patients that could have met CT scan screening criteria and demonstrated that 1,351 of the participants developed primary lung cancer, with the incidence of the disease dropping by a third among men, and rising by 8% among women during the study period. The proportion of women that could have met the criteria fell from 52 to 37%, and from 60 to 50% among men. In addition, the research concluded that between 1984 and 1990, the proportion of patients eligible for screening dropped 57%, and between 2005 and 2011 it decreased 43%.
Yang believes that the findings of the study demonstrate the importance of CT screening regarding the proportion of lung cancer patients who smoked before or after the criteria set by the Task Force. “While more people have quit for a longer periods of time, they are still getting lung cancer, and they make up a larger proportion of newly diagnosed lung cancer patients,” added the epidemiologist.