Tumor Volume Is a Better Prognostic Factor than Greatest Tumor Diameter in Operated Stage I-III Non-Small-Cell Lung Cancer

Abstract

Introduction: The aim of this study was to investigate the prognostic impact of tumor volume (TV, recorded from surgical specimens) on patients with stage I-III non-small-cell lung cancer (NSCLC) after complete resection.

Materials and methods: A total of 129 patients with stage I-III NSCLC diagnosed and underwent curative resection from 2007 to 2014 in our center were included in the study. Their clinico-pathological factors were retrospectively reviewed. Overall survival (OS) and disease-free survival (DFS) analyses were performed with the Kaplan-Meier method and Cox's hazard model. According to the ROC analysis, patients were divided into 2 groups (Group 1: 58 patients <30.3 cm³ and Group 2: 71 patients ≥30.3 cm³) and the OS and DFS values were compared.

Results: Median TVs and greatest tumor diameter were 12 cm³ (0.1-30) / 3 cm (0.4-6.5) in Group 1 and 98 cm³ (30.6-1521) / 6 cm (3.5-21) in Group 2. Median OS was 53 (5-177) months in Group 1 and 38 (2-200) months in Group 2 (P < .001). DFS was similar in both group (28 [1-140] vs. 24 [1-155] months, Introduction P = .489). Kaplan-Meier curves showed significantly higher OS rates in Group 1 than Group 2 (P = .04). In multivariable analysis (TV, tumor T stage, tumor N stage, receiving adjuvant radiotherapy) showed that TV (HR: 0.293, 95% CI: 0.121-0.707, P = .006) and tumor N stage (HR: 0.013, 95% CI: 0.001-0.191, P = .02) were independent factors associated with OS.

Conclusion: Tumor volume, not considered in the routine TNM classification, may improve prediction accuracy of overall OS in operated Stage I-III NSCLC.

Keywords: Disease-free survival; Nonsmall-cell lung cancer; Overall survival; Tumor size; Tumor volume.