Prognostic value of volumetric PET parameters in unresectable and metastatic esophageal cancer

Abstract

Purpose: To assess the prognostic value of volumetric parameters measured with PET/CT in patients with advanced or metastatic esophageal cancer (EC).

Materials and methods: We identified 71 patients (33 adenocarcinoma [AC] and 38 squamous cell carcinoma [ESCC]) with unresectable or metastatic EC who had PET/CT prior to palliative treatment. Volumetric parameters (metabolic tumor volume [MTV], total lesion glycolysis [TLG], tumor length [TL]) as well as maximum and mean standardized uptake (SUVmax, SUVmean) were obtained from (18)F-FDG PET/CT studies. The correlation between overall survival (OS) and established clinical parameters was assessed using a Cox proportional hazards model.

Results: ESCC patients had higher SUVmax and SUVmean compared to AC (p=0.002 and p<0.001, respectively). There was an association of lower SUVmax and SUVmean with metastatic compared to locally advanced tumors (e.g., median SUVmax stage IV: 14.9, 95% confidence interval [95% CI 4.4-35.5] vs. stage IIIA-C: 23.3 [9.2-40.6], p=0.017). TL, MTV and TLG showed an association to OS for all patients and for the subgroup of AC patients (AC; TL: Hazard ratio [HR] 3.23, [95% CI 1.03-10.11], p=0.044; MTV: HR 3.16, [95% CI 1.08-9.23], p=0.035). There was no correlation between PET parameters and survival in ESCC patients. Clinical nodal status was the only clinical variable associated to OS (HR 2.45 [95% CI 1.26-4.75], p=0.008) in AC patients. In a multivariate analysis, nodal status and MTV remained as independent factors associated to OS (N: HR 9.98, [95% CI 1.28-78.11], p=0.028; MTV: HR 1.02, [95% CI 1.01-1.03], p=0.003).

Conclusions: MTV predicted poor OS in patients with advanced AC. No PET parameters were associated to OS in ESCC patients.

Keywords: F18-PET/CT; Metabolic tumor volume; Oesophageal cancer; Outcome analysis; SUV.