Abstract
ObjectiveDuring neoadjuvant chemoradiotherapy for oesophageal cancer, or in the interval prior to surgery, some patients develop systemic metastasis. This study aimed to evaluate the diagnostic performance of 18F-FDG PET/CT for the detection of interval metastasis and to identify predictors of interval metastases in a large cohort of oesophageal cancer patients.MethodsIn total, 783 consecutive patients with potentially resectable oesophageal cancer who underwent chemoradiotherapy and pre- and post-treatment 18F-FDG PET/CT between 2006 and 2015 were analyzed from a prospectively maintained database. Diagnostic accuracy measures were calculated on a per-patient basis using histological verification or clinical follow-up as a reference standard. Multivariable logistic regression analysis was performed to determine pre-treatment predictors of interval metastasis. A prediction score was developed to predict the probability of interval metastasis.ResultsOf 783 patients that underwent 18F-FDG PET/CT restaging, 65 (8.3%) were found to have interval metastasis and 44 (5.6%) were deemed to have false positive lesions. The resulting sensitivity and specificity was 74.7% (95% CI: 64.3–83.4%) and 93.7% (95% CI: 91.6–95.4%), respectively. Multivariable analysis revealed that tumor length, cN status, squamous cell tumor histology, and baseline SUVmax were associated with interval metastasis. Based on these criteria, a prediction score was developed with an optimism adjusted C-index of 0.67 that demonstrated accurate calibration.Conclusions18F-FDG PET/CT restaging detects distant interval metastases in 8.3% of patients after chemoradiotherapy for oesophageal cancer. The provided prediction score may stratify risk of developing interval metastasis, and could be used to prioritize additional restaging modalities for patients most likely to benefit.
Highlights
Oesophageal cancer affects more than 450,000 people annually, and is the sixth leading cause of cancer-related mortality worldwide [1]
Patients were excluded if the time interval between completion of chemoradiotherapy and 18F-FDG PET/CT restaging was more than 3 months
A total of 783 patients diagnosed with oesophageal cancer who met our inclusion and exclusion criteria underwent chemoradiotherapy followed by a restaging 18F-FDG PET/CT scan (Fig. 1)
Summary
Oesophageal cancer affects more than 450,000 people annually, and is the sixth leading cause of cancer-related mortality worldwide [1]. Surgical resection of the esophagus preceded by neoadjuvant chemoradiotherapy is the standard of care for patients with non-metastasized oesophageal cancer [1,2,3]. Eur J Nucl Med Mol Imaging (2018) 45:1742–1751 subsequent waiting time to surgery, systemic interval metastases may develop that were not visible during baseline staging [6,7,8]. In these patients curative treatment is no longer possible [9]. There is disagreement between guidelines as to whether all patients should be restaged after chemoradiotherapy [10,11,12]. Little is known about which patients are at risk of developing interval metastases
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