Semiautomatic analysis on computed tomography in locally advanced or metastatic non-small cell lung cancer: Reproducibility and Prognostic Significance of Unidimensional and 3-dimensional Measurements.

Purpose: The aim of the study was to compare both reproducibility and prognostic value of lesion size measurements obtained manually and semiautomatically on computed tomography in advanced non-small cell lung cancer (NSCLC). Materials and Methods: Manual axial longest diameter, semiautomatic axial longest diameter, and volume of NSCLC lesions were independently analyzed by 4 readers at baseline and after at least 1 cycle of platinum-based chemotherapy. The prognostic value of the proportional change in lesion size between baseline and follow-up CT was evaluated using either RECIST or experimental thresholds derived from the quartiles of the changes as assessed manually or semiautomatically. Results: Semiautomatic axial longest diameter (concordance correlation coefficient [CCC]: 0.980 to 0.987; variation coefficient [VC%]: 6% to 7.3%) and volume (CCC: 0.974 to 0.991; VC%: 5.6% to 9.5%) were more reproducible than manual axial longest diameter (CCC: 0.950 to 0.984; VC%: 6.4% to 11.7%). RECIST categories did not stratify patients with different survival durations. For 3/4 readers, a decrease of ≤70% in lesion volume was associated with shorter survival (median survival: 11 mo, P<0.05; hazard ratio: 5 to 22.2, P<0.05). Conclusions: In advanced NSCLC, semiautomatic measures were more reproducible than manual diameter, and volumetric measurement may better predict patient survival.