Defining risk groups of patients with cancer of?unknown primary site and cervical nodal metastases by F-18 fluorodeoxyglucose positron emission tomography and computed tomography imaging

摘要

We sought to investigate the clinical utility of F-18 fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/CT) in Taiwanese patients with cancer of unknown primary site (CUP) and cervical nodal metastases. We also aimed to study the impact of F-18 FDG PET/CT on clinical treatment priority in this patient group. Between September 2006 and May 2014, patients with CUP and cervical nodal metastases who underwent F-18 FDG PET/CT imaging study were retrospectively identified. The clinicopathological risk factors and PET parameters were analyzed in relation to 2-year overall survival (OS) rates using univariate and multivariate analyses. Two-year OS curves were plotted with the Kaplan–Meier method. Of the eligible patients ( n ?=?54), 12 (22.2%) had distant metastases (DM) at presentation. A total of 13 (24.1%) and 15 (27.8%) primary tumors were identified by FDG PET/CT imaging and an additional triple biopsy, respectively. The results of multivariate analysis identified smoking [ p ?=?0.033, 95% confidence interval (CI)?=?1.197?40.342], a maximum standardized uptake value (SUV max ) of cervical nodes?≥?14.2 ( p ?=?0.035, 95% CI?=?1.134?28.029), and DM at presentation ( p ?=?0.031, 95% CI?=?1.257?114.854) as independent predictors of 2-year OS. Specifically, patients who carried ≥ 2 risk factors showed poorer outcomes (70.3% vs. 11.8%, p ??0.001). Fifteen study patients (27.8%) had their treatment modified by FDG PET/CT findings. We conclude that FDG PET/CT is clinically useful in CUP patients not only for tumor staging, but also for modifying treatment regimens.