Despite the favorable prognosis of stage IA non-small cell lung cancer (NSCLC), the disease recurs after complete surgical resection in 20%-30% of patients. This study determined the prognostic value of various metabolic parameters of (18)F-FDG PET/CT in surgically resected stage IA NSCLC.
Methods: We retrospectively reviewed 248 patients with stage IA NSCLC who underwent lobectomy and complete lymph node dissection after PET/CT. A region of interest was drawn on the primary lesion, and metabolic indices such as metabolic tumor volume, maximum standardized uptake value (SUV(max)), and total lesion glycolysis (TLG) were measured using an SUV cutoff of 2.5.
Results: The patients included 134 men and 114 women, and the mean age was 63.03 ± 10.01 y; 129 were stage T1a (≤ 2 cm) and 119 were T1b (>2 cm). The median follow-up period was 36.6 mo. Recurrence took place in 15 patients. The mean (± SD) SUV(max), metabolic tumor volume, and TLG were 4.55 ± 3.75, 5.92 ± 5.57, and 14.42 ± 17.35, respectively. The cutoffs of SUV(max) and TLG were 3.7 and 13.76, respectively. The 5-y overall survival (OS) was 95.1% in low-SUV(max) patients and 82.2% in high-SUV(max) patients (P = 0.02). The 5-y OS was 93.7% in low-TLG patients and 78.3% in high-TLG patients (P = 0.01). On multivariate analysis, TLG was a risk factor for OS (hazard ratio, 3.159; P = 0.040), but SUV(max) showed marginal significance (P = 0.064). The concordance index of the TLG model was 0.676 (95% CI, 0.541-0.812).
Conclusion: TLG was a significant prognostic factor for OS in patients with stage IA NSCLC.
Keywords: PET-CT; lung cancer surgery; statistics; survival analysis; volume-dependent parameter.
© 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.