Assessment of Lung Cancer Risk Among Smokers for Whom Annual Screening Is Not Recommended

Abstract

ImportanceThe US Preventive Services Task Force does not recommend annual lung cancer screening with low-dose computed tomography (LDCT) for adults aged 50 to 80 years who are former smokers with 20 or more pack-years of smoking who quit 15 or more years ago or current smokers with less than 20 pack-years of smoking.ObjectiveTo determine the risk of lung cancer in older smokers for whom LDCT screening is not recommended.Design, Settings, and ParticipantsThis cohort study used the Cardiovascular Health Study (CHS) data sets obtained from the National Heart, Lung and Blood Institute, which also sponsored the study. The CHS enrolled 5888 community-dwelling individuals aged 65 years and older in the US from June 1989 to June 1993 and collected extensive baseline data on smoking history. The current analysis was restricted to 4279 individuals free of cancer who had baseline data on pack-year smoking history and duration of smoking cessation. The current analysis was conducted from January 7, 2022, to May 25, 2022.ExposuresCurrent and prior tobacco use.Main Outcomes and MeasuresIncident lung cancer during a median (IQR) of 13.3 (7.9-18.8) years of follow-up (range, 0 to 22.6) through December 31, 2011. A Fine-Gray subdistribution hazard model was used to estimate incidence of lung cancer in the presence of competing risk of death. Cox cause-specific hazard regression models were used to estimate hazard ratios (HRs) and 95% CIs for incident lung cancer.ResultsThere were 4279 CHS participants (mean [SD] age, 72.8 [5.6] years; 2450 [57.3%] women; 663 [15.5%] African American, 3585 [83.8%] White, and 31 [0.7%] of other race or ethnicity) included in the current analysis. Among the 861 nonheavy smokers (<20 pack-years), the median (IQR) pack-year smoking history was 7.6 (3.3-13.5) pack-years for the 615 former smokers with 15 or more years of smoking cessation, 10.0 (5.3-14.9) pack-years for the 146 former smokers with less than 15 years of smoking cessation, and 11.4 (7.3-14.4) pack-years for the 100 current smokers. Among the 1445 heavy smokers (20 or more pack-years), the median (IQR) pack-year smoking history was 34.8 (26.3-48.0) pack-years for the 516 former smokers with 15 or more years of smoking cessation, 48.0 (35.0-70.0) pack-years for the 497 former smokers with less than 15 years of smoking cessation, and 48.8 (31.6-57.0) pack-years for the 432 current smokers. Incident lung cancer occurred in 10 of 1973 never smokers (0.5%), 5 of 100 current smokers with less than 20 pack-years of smoking (5.0%), and 26 of 516 former smokers with 20 or more pack-years of smoking with 15 or more years of smoking cessation (5.0%). Compared with never smokers, cause-specific HRs for incident lung cancer in the 2 groups for whom LDCT is not recommended were 10.54 (95% CI, 3.60-30.83) for the current nonheavy smokers and 11.19 (95% CI, 5.40-23.21) for the former smokers with 15 or more years of smoking cessation; age, sex, and race–adjusted HRs were 10.06 (95% CI, 3.41-29.70) for the current nonheavy smokers and 10.22 (4.86-21.50) for the former smokers with 15 or more years of smoking cessation compared with never smokers.Conclusions and RelevanceThe findings of this cohort study suggest that there is a high risk of lung cancer among smokers for whom LDCT screening is not recommended, suggesting that prediction models are needed to identify high-risk subsets of these smokers for screening.

Lung cancer diagnosis and mortality beyond 15 years since quit in individuals with a 20+ pack‐year history: A systematic review

“…Six fair‐quality studies provide moderate‐certainty evidence that the relative risk (RR) or odds of lung cancer remains elevated beyond 15 YSQ (see Tables 3 and ) 13,14,19,20,33,34 . Three prospective cohort studies (i.e., the CPS‐II nutrition cohort, n = 184,194 33 ; the Cardiovascular Health Study, n = 4279 19 ; and the Framingham Heart Study, n = 8907), 13,19,33 one case–control study (BLCS, n = 5503), 34 and one cross‐sectional analysis (PLCO, n = 108,526), 14 were conducted in the United States. The remaining study was the Singapore Chinese Health Study ( n = 48,251), 20 which examined a cohort of Chinese residents living in Singapore 20 .…”

“…Three fair-quality studies contribute to low-certainty evidence that lung cancer incidence remains elevated beyond 15 YSQ (see Tables 3 and S4). 14,19,20 A prospective cohort study (the Cardiovascular Health Study, n = 4279) reported cumulative incidences of 5.0% and 10.1% versus 0.5% when comparing those who had ≥15 YSQ versus <15 YSQ, respectively, with individuals who never smoked (Tables 2 and 4). 19 Two articles reported lung cancer incidence rates beyond 15 YSQ.…”

“…14,19,20 A prospective cohort study (the Cardiovascular Health Study, n = 4279) reported cumulative incidences of 5.0% and 10.1% versus 0.5% when comparing those who had ≥15 YSQ versus <15 YSQ, respectively, with individuals who never smoked (Tables 2 and 4). 19 Two articles reported lung cancer incidence rates beyond 15 YSQ. One study was a cross-sectional analysis of the National Cancer Institute's Prostate Lung Colorectal Ovarian (PLCO) Cancer Screening Trial data (n = 108,526), 14 and the other was a prospective cohort study of Chinese residents in Singapore (the Singapore Chinese Health Study, n = 48,251).…”

Effectiveness of a single low‐dose computed tomography screening for lung cancer: A population‐based perspective cohort study in China

“…The US Preventive Services Task Force(USPSTF) recommends annual lung cancer screening with LDCT for adults aged 50 to 80 years with a history of ≥20 pack‐years of smoking and currently smoke or had quit within the past 15 years 28 . In a recent study, compared with non‐smokers, though the lung cancer incidence of heavy smokers (≥20 pack‐year smoking history and ≥15 years since quitting) increased significantly, the incidence in non‐heavy smokers (<20 pack‐year smoking history among former smokers and ≥15 years since quitting or <15 years since quitting and current smoker) also significantly increased from 3.09 to 9.35 29 . Although studies in Henan, China showed that smokers with a smoking history of ≥30 pack‐years was a risk factor for lung cancer, 30 the above study indicated that smokers not recommended to undergo LDCT screening need to be identified as high‐risk subsets for screening as well.…”

Machine Learning and Real-World Data to Predict Lung Cancer Risk in Routine Care

“…Further, the majority of lung cancers are diagnosed in individuals that do not meet screening eligibility criteria ( 4 ). Despite the expanded screening eligibility with the revised United States Preventive Services Task Force (USPSTF) guidelines ( 5 ), individuals that do not meet screening criteria have a high risk of lung cancer ( 6 ), supporting the need for prediction tools that can facilitate the identification of high-risk individuals and the adoption of screening in clinical practice.…”