Ratio of maximum standardized uptake value to primary tumor size is a prognostic factor in patients with advanced non-small cell lung cancer

Purpose: Ratio of maximum standardized uptake value to primary tumor size (SUVmax/tumor size) was previously demonstrated to be a more important indicator of prognosis than primary tumor SUVmax alone in surgically resected non-small cell lung cancer (NSCLC). The aim of this study was to investigate whether SUVmax/tumor size was associated with response to first-line therapy and prognosis in patients with advanced NSCLC.

Patients and methods: A retrospective review of patients who had a pretreatment (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) before receiving first-line therapy for advanced (III & IV) NSCLC was performed. Survival curves were stratified by median SUVmax and SUVmax/tumor size by the Kaplan-Meier method and statistical differences were assessed using the log-rank test. Multivariate proportional hazards (Cox) regression analyses were applied to test the SUVmax's and SUVmax/tumor size's independency of other prognostic factors for the prediction of survival.

Results: In total 181 patients were enrolled into the current study. Median overall survival (OS) was 15.4 months (range, 3.1-64.0 months), progression-free survival (PFS) was 5.6 months (range, 0.8-29.1 months), and post-progression survival (PPS) was 8.2 months (range, 0-51.3 months). The statistical analysis data indicated that only clinical response to first-line therapy (P=0.000, OR =6.555) was independent prognostic factors for PFS, stage (P=0.028, OR =1.673) was associated with PPS independently, and for OS, SUVmax/tumor size (P=0.050, OR =1.656) and clinical response (P=0.002, OR =2.803) were all independent prognostic factors.

Conclusions: SUVmax/tumor size may be an important indicator of prognosis in patients with advanced NSCLC.