Decline in Proportion of Lung Cancer Patients Meeting Screening Criteria
In a study reported in a research letter in JAMA, Wang et al found that the proportion of patients with lung cancer who would have met U.S. Preventive Services Task Force (USPSTF) criteria for low-dose computed tomography (CT) lung screening decreased significantly between the periods of 1984 to 1990 and 2005 to 2011. A minority of patients with lung cancer in the latter period satisfied the screening criteria.
Study Details
The study involved a retrospective analysis including all approximately 140,000 Olmsted County, Minnesota, residents aged > 20 years from 1984 through 2011. Overall, 83% of residents were white. All pathologically confirmed incident cases of primary lung cancer were identified using the Rochester Epidemiology Project database, which has maintained a comprehensive medical records linkage system for > 60 years. Cases were grouped into four 7-year intervals. The USPSTF criteria for low-dose CT screening identified individuals aged 55 to 80 years with a 30 pack-year smoking history who were current smokers or had quit within the past 15 years.
Decreased Incidence Rate in Men
Overall, 1,351 patients were diagnosed with primary lung cancer between 1984 and 2011. Patients had a mean age of 68 years and 55% were male. The age- and sex-adjusted incidence rate decreased from 52.3 per 100,000 person-years in 1984 to 1990 to 44.1/100,000 person-years in 2005 to 2011 (P < .001). Over this period, there was a decrease in incidence rate in men (P = .007 for trend) but not in women (P = .14 for trend).
Changes According to Smoking Status and Quit Time
Over the study period, the proportion of patients with lung cancer who were former smokers increased (from 38% to 46%, P = .002 for trend) and the proportion who were current smokers decreased (from 52% to 45%, P = .003 for trend). The proportion of cases who had a history of < 30 pack-years increased (from 13% to 20%, P < .001 for tend) and the proportion with ≥ 30 pack-years declined (from 87% to 81%, P < .001 for trend). Among former smokers, the proportion of cases in those who had quit for < 15 years decreased (from 69% to 62%, P < .001 for trend) and the proportion of those who had quit for ≥ 15 years increased (from 31% to 38%, P < .001 for trend).
Meeting Screening Criteria
The proportion of cases meeting the USPSTF criteria decreased from 56.8% in 1984 to 1990 to 43.3% in 2005 to 2011 (P < .001 for trend). Significant reductions in proportion meeting criteria were observed in both women (from 52.3% to 36.6%, P = .005) and in men (from 60.0% to 49.7%, P = .03).
The investigators concluded: “The proportion of patients with lung cancer in Olmsted County meeting the USPSTF screening criteria decreased significantly between 1984 and 2011….Our findings may reflect a temporal change in smoking patterns in which the proportion of adults with a 30 pack-year smoking history and having quit within 15 years declined. The secular trends in lung cancer incidence rates in Olmsted County are comparable with U.S. Surveillance, Epidemiology and End Results registry data, but may not be generalizable to the entire U.S. population. The decline in the proportion of patients meeting USPSTF high-risk criteria indicates that an increasing number of patients with lung cancer would not have been candidates for screening. More sensitive screening criteria may need to be identified while balancing the potential harm from computed tomography.”
Ping Yang MD, PhD, of Mayo Clinic, Rochester, is the corresponding author for the JAMA research letter.
The study was supported by grants from the National Institutes of Health, the National Institute on Aging, and funding from the Mayo Clinic Foundatin. The study authors reported no potential conflicts of interest.
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