Effectiveness of Repeat 18F-Fluorodeoxyglucose Positron Emission Tomography Computerized Tomography (PET-CT) Scan in Identifying Interval Metastases for Patients with Esophageal Cancer.

INTRODUCTION

An 18F-fluorodeoxyglucose positron emission tomography-computerized tomography (PET-CT) scan is performed after neoadjuvant chemoradiation (nCRT) to restage esophageal cancer. The purpose of this study was to determine the ability of PET-CT to accurately identify interval metastatic disease following nCRT.

METHODS

This was a single-institution retrospective review (January 2005-February 2012) of patients with esophageal cancer treated with nCRT who underwent pre- and post-nCRT PET-CT.

RESULTS

A total of 283 patients were treated with nCRT, of whom 258 (91.2%) had both a pre- and post-nCRT PET-CT. On the post-nCRT PET-CT, 64 patients (24.8%) had interval findings concerning for metastatic disease. Of these patients, only 10 (15.6%) had true-positive findings of metastatic disease (six biopsy proven). The sites of interval metastases included bone (4), liver (3), peritoneum (1), mediastinal lymph nodes (1), and cervical lymph nodes (1). The positive predictive value of post-nCRT PET-CT for interval metastases was 15.6% (10/64), and the yield for detecting metastases since the pre-nCRT PET-CT was 3.9% (10/258). The work-up of the 54 patients (20.9% of the initial starting group) with false-positive post-nCRT findings included biopsy (24.6%) and immediate additional imaging (45.2%). A total of 208 patients proceeded with surgery: 163 (78.4%) had no new findings on post-nCRT PET-CT, and 45 (21.6%) had new false-positive findings. False-positive sites mainly included the lung (15) and liver (14).

CONCLUSIONS

The yield of post-nCRT PET-CT for the detection of new metastatic disease was 3.9%. Post-nCRT PET-CT often leads to a high proportion of false positives and subsequent investigational work-up.