Nanda Horeweg MD, Abstract Co-Author: Nothing to Disclose

Joost Van Rosmalen PhD, Abstract Co-Author: Nothing to Disclose

Marjolein Anne Heuvelmans BSc, Abstract Co-Author: Nothing to Disclose

Carlijn Van Der Aalst PhD, Abstract Co-Author: Nothing to Disclose

Harry De Koning, Abstract Co-Author: Research Grant, F. Hoffman-La Roche Ltd Equipment support, Siemens AG Medical Advisory Board, F. Hoffman-La Roche Ltd

Matthijs Oudkerk MD, PhD, Abstract Co-Author: Nothing to Disclose

Rozemarijn Vliegenthart MD, PhD, Presenter: Nothing to Disclose

Ernst T. Scholten MD, Abstract Co-Author: Nothing to Disclose

Kristiaan Nackaerts MD, PhD, Abstract Co-Author: Speaker, Pfizer Inc Speaker, Novartis AG Advisory Board, Pfizer Inc Travel support, AstraZeneca PLC Travel support, Eli Lilly and Company

Jan-Willem J. Lammers MD, PhD, Abstract Co-Author: Nothing to Disclose

Harry Groen, Abstract Co-Author: Nothing to Disclose

Carla Weenink MD, PhD, Abstract Co-Author: Nothing to Disclose

Erik Thunnissen MD, PhD, Abstract Co-Author: Nothing to Disclose

Peter M.A. Van Ooijen, Abstract Co-Author: Nothing to Disclose

Willem P. Mali MD, PhD, Abstract Co-Author: Nothing to Disclose

The main challenge in computed tomography (CT) screening for lung cancer is the high prevalence of pulmonary nodules and the relatively low incidence of lung cancer. Thresholds for nodule size and growth rate, which determine which nodules require additional diagnostic measures, should be based on the lung cancer probability of the individual.

The diameter, volume and volume-doubling time (VDT) of 9,681 non-calcified nodules detected in 7,135 participants in the Dutch-Belgian lung cancer screening trial were used to quantify their lung cancer probability. Complete coverage on all lung cancer diagnoses was obtained by linkages with the national cancer registry, for a follow-up of eight years. The probabilities were used to propose and evaluate optimized thresholds for CT-detected nodules.

Lung cancer probability was low in subjects with a nodule volume <100mm³ (≤0.7%) or maximum transverse diameter <5mm (≤0.5%). Moreover, probability in these subjects was not significantly different from that in subjects without nodules (0.4%). Lung cancer probability was intermediate for nodule volumes 100-300mm³ (1.5-5.8%) and diameters 5-10mm (0.9-2.9%); the VDT further stratified the probability: 0.0-0.9% for VDTs>600days, 4.0% for VDTs 400-600days and 6.7-25.0% for VDTs<400days. Lung cancer probability was high for participants with nodule volumes ≥300mm³ (8.9-26.1%) or diameters ≥10mm (11.1-26.2%), even with long VDTs.

Subjects with nodules <100mm³ or <5mm have a lung cancer risk that is not significantly different from that in subjects without nodules and do not require additional evaluation. Individuals with nodules 100-300mm³ or 5-10mm represent an indeterminate subgroup for whom the assessment of VDT is appropriate (<400days warrants diagnostic work-up). However, the risk for subjects with nodules ≥300mm³ or ≥10mm demands immediate diagnostic evaluation.

This study provides detailed and reliable data on the lung cancer probability of subjects with CT-detected nodules stratified by nodule diameter, volume and growth rate. This information can be valuab

Horeweg, N, Van Rosmalen, J, Heuvelmans, M, Van Der Aalst, C, De Koning, H, Oudkerk, M, Vliegenthart, R, Scholten, E, Nackaerts, K, Lammers, J, Groen, H, Weenink, C, Thunnissen, E, Van Ooijen, P, Mali, W, Lung Cancer Probability in Subjects with CT-detected Pulmonary Nodules.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13026911.html