Results of the Pan-Canadian Early Detection of Lung Cancer (PanCan) study, reported in The Lancet Oncology by Tammemagi et al, indicate that the PanCan risk model is effective in identifying persons found to have early-stage lung cancer on low-dose computed tomography (CT) screening.
In the study, individuals aged 50 to 75 years who were ever-smokers and had no self-reported history of lung cancer were recruited at 8 centers across Canada. Eligible participants had to have a ≥ 2% 6-year risk of lung cancer, as estimated by the PanCan model; the risk variables in the model are age, smoking duration, pack-years, family history of lung cancer, education level, body mass index, chest x-ray in the past 3 years, and history of chronic obstructive pulmonary disease. Eligible individuals were screened with low-dose CT at baseline (T0) and at 1 (T1) and 4 (T4) years. The primary outcome of the study was the incidence of lung cancer.
A total of 7,044 individuals were considered for enrollment, with 2,537 eligible participants enrolled between September 2008 and December 2010. After a median follow-up of 5.5 years, 172 lung cancers were diagnosed in 164 individuals, yielding a cumulative incidence of 0.065 and an incidence rate of 138.1 per 10,000 person-years. A total of 10 interval lung cancers (6% of detected cancers) were found, including 1 between T0 and T1 and 9 between T1 and T4. Of the 172 cancers detected by low-dose CT, 137 (80%) were identified at T0; 8 (5%), at T1; 8 (5%), at T2; and 17 (10%), at T4.
The cumulative incidence of lung cancer was higher than that observed in theNational Lung Screening Trial(NLST; 6.5% vs 4.0%, P < .0001). Overall, 133 (77%) of lung cancers detected were stage I or II, compared with 593 of 1,040 (57%) identified in NLST (P < .0001).
The investigators concluded: “The PanCan model was effective in identifying individuals who were subsequently diagnosed with early, potentially curable, lung cancer. The incidence of cancers detected and the proportion of early stage cancers in the screened population was higher than observed in previous studies. This approach should be considered for adoption in lung cancer screening programmes.”
The study was funded by the Terry Fox Research Institute and Canadian Partnership Against Cancer.
Stephen Lam, MD, of the British Columbia Cancer Agency, is the corresponding author of The Lancet Oncology article.
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