Prognostic performance in lung cancer according to tumor size: Comparison of axial, multiplanar, and 3-dimensional CT measurement to pathological size

Abstract

Purpose: This study aimed to compare the prognostic performance of clinical T staging based on axial, multiplanar, and 3-dimensional measurement on CT with that of pathological T staging in patients with non-small cell lung cancer.

Method: Patients with surgically resected lung cancer without pathological node metastasis between June 2010 and December 2017 were retrospectively included. Clinical T stages were determined based on the maximal tumor size on axial, multiplanar (axial, coronal, and sagittal) images and 3-dimensional tumor mask. The prognostic performances of clinical and pathological T staging for disease-free survival (DFS) were compared using the concordance indices (C-indices).

Results: A total of 544 patients (64.7 +/- 9.7 years, 352 men) were included; 160 patients (29.4%) experienced events including 29 (5.3%) who expired. The median DFS was 44.1 months. The mean tumor size on axial, multiplanar images, 3-dimensional tumor mask, and pathology was 30.8 +/- 17.3, 33.9 +/- 19.4, 39.2 +/- 21.4, and 33.4 +/- 18.0 mm, respectively. Clinical staging based on multiplanar measurement showed a higher agreement (67.5% [367/544]) with pathological staging than axial (60.5% [329/544]) and 3-dimensional measurement (50.9% [277/544]) based staging did (p = .0005 and <.0001, respectively). The adjusted C-indices of axial, multiplanar, 3-dimensional, and pathological tumor stages were 0.66 (95% confidence interval [CI]: 0.66-0.67), 0.66 (95% CI: 0.66-0.66), 0.67 (95% CI: 0.67-0.67), and 0.67 (95% CI: 0.66-0.67), respectively (p > .05).

Conclusions: The prognostic performances of tumor staging according to size measurement methods were not significantly different. Multiplanar measurement may be preferable for clinical staging considering its highest agreement with pathological staging.