Restaging oesophageal cancer after neoadjuvant therapy with ¹⁸F-FDG PET-CT: identifying interval metastases and predicting incurable disease at surgery

It is unknown whether restaging oesophageal cancer after neoadjuvant therapy with positron emission tomography-computed tomography (PET-CT) is more sensitive than contrast-enhanced CT for disease progression. We aimed to determine this and stratify risk.

This was a retrospective study of patients staged before neoadjuvant chemotherapy (NAC) by ¹⁸F-FDG PET-CT and restaged with CT or PET-CT in a single centre (2006-2014).

Three hundred and eighty-three patients were restaged (103 CT, 280 PET-CT). Incurable disease was detected by CT in 3 (2.91 %) and PET-CT in 17 (6.07 %). Despite restaging unsuspected incurable disease was encountered at surgery in 34/336 patients (10.1 %). PET-CT was more sensitive than CT (p = 0.005, McNemar’s test). A new classification of FDG-avid nodal stage (mN) before NAC (plus tumour FDG-avid length) predicted subsequent progression, independent of conventional nodal stage. The presence of FDG-avid nodes after NAC and an impassable tumour stratified risk of incurable disease at surgery into high (75.0 %; both risk factors), medium (22.4 %; either), and low risk (3.87 %; neither) groups (p < 0.001). Decision theory supported restaging PET-CT.

PET-CT is more sensitive than CT for detecting interval progression; however, it is insufficient in at least higher risk patients. mN stage and response (mNR) plus primary tumour characteristics can stratify this risk simply.

• Restaging ¹⁸ F-FDG-PET-CT after neoadjuvant chemotherapy identifies metastases in 6 % of patients

• Restaging ¹⁸ F-FDG-PET-CT is more sensitive than CT for detecting interval progression