• International Agency for Research on Cancer, Lyon, France. Electronic address: RobbinsH@iarc.fr.
• Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland.
• University of Nottingham, Nottingham, United Kingdom.

OBJECTIVE: We propose a risk-tailored approach for management of lung cancer screening results. This approach incorporates individual risk factors and LDCT image features into calculations of immediate and next-screen (1-year) risks of lung cancer detection, which in turn can recommend short-interval imaging or 1-year or 2-year screening intervals.

METHODS: We first extended the "LCRAT+CT" individualized risk calculator to predict lung cancer risk after either a negative or abnormal LDCT screen. To develop the abnormal screens portion, we analyzed 18,129 abnormal LDCTs in the National Lung Screening Trial (NLST), including lung cancers detected immediately (n=649) or at the next screen (n=235). We estimated the potential impact of this approach among NLST participants with any screen result (negative or abnormal).

RESULTS: Applying the draft National Health Service (NHS) England protocol for lung screening to NLST participants referred 76% of participants to a 2-year interval, but delayed diagnosis for 40% of detectable cancers. The LCRAT+CT risk model, with a threshold of <0.95% cumulative lung-cancer risk, would also refer 76% of participants to a 2-year interval, but would delay diagnosis for only 30% of cancers, a 25% reduction versus the NHS protocol. Alternatively, LCRAT+CT, with a threshold of <1.7% cumulative lung-cancer risk, would also delay diagnosis for 40% of cancers, but would refer 85% of participants for a 2-year interval, a 38% further reduction in the number of required 1-year screens beyond the NHS protocol.

CONCLUSIONS: Using individualized risk models to determine management in lung cancer screening could substantially reduce the number of screens or increase early detection.