Prognostic Significance of Standardized Uptake Value of Lymph Nodes on Survival for Stage III Non-small Cell Lung Cancer Treated With Definitive Concurrent Chemoradiotherapy

Abstract

Objectives: Definitive concurrent chemoradiotherapy is the standard treatment for stage III non-small cell lung cancer (NSCLC). Previous studies showed that the tumor size and its metabolic activity are predictors of treatment outcome. We investigated whether there are new metabolic prognostic factors of survival for stage III NSCLC after definitive concurrent chemoradiotherapy.

Patients and methods: A total of 57 consecutive patients treated with definitive concurrent chemoradiotherapy for their stage IIIA (n=22) and stage IIIB (n=35) (AJCC 7th edition) unresectable NSCLC were identified. A total of 43 (75.4%) patients had positron emission tomography with integrated computed tomography (PET-CT) scan performed at diagnosis that were subsequently reviewed and analyzed. Prognosticators of progression-free survival (PFS), distant metastasis-free survival (DMFS), and overall survival (OS) were analyzed.

Results: The median PFS, DMFS, and OS were 14.1, 12.6, and 37.8 months, respectively, after a median follow-up of 41.5 months. PFS advantage was demonstrated in stage IIIA versus stage IIIB (median 38.6 vs. 13.5 mo, P=0.020), N-stage N0-N2 versus N3 (median 16.7 vs. 8.1 mo, P<0.001), planning target volume (PTV) <500 versus ≥500 cm (median 23.6 vs. 11.3 mo, P=0.008), and the maximum standardized uptake value (SUVmax) nodes <8 versus ≥8 (median 16.1 vs. 10.7 mo, P=0.048). DMFS advantage was noted in those with PTV<500 versus PTV≥500 cm (median 13.0 vs. 11.3 mo, P=0.045) and SUVmax nodes <8 versus ≥8 (median 13.5 vs. 8.0 mo, P=0.050). OS advantage was revealed in stage IIIA versus stage IIIB (median 56.5 vs. 22.7 mo, P=0.013) and SUVmax nodes <8 versus ≥8 (42.3 vs. 12.8 mo, P=0.009). Multivariate analysis demonstrated that SUVmax nodes <8 was the only prognostic factor of PFS, DMFS, and OS. Metabolic tumor volume and total lesion glycolysis were not prognostic factors.

Conclusions: SUVmax nodes <8 was the only prognostic factor of PFS, DMFS, and OS in our study. PET-CT scan at the time of diagnosis is useful in stratifying patients into favorable and unfavorable groups in stage III NSCLC treated with definitive concurrent chemoradiotherapy.