OGC P05 18FDG-PET-CT is superior to CT in detecting locoregional and distant recurrence after oesophago-gastrectomy for distal oesophageal/gastro-oesophageal junctional cancer

Abstract Background Recurrent oesophageal and gastro-oesophageal junctional cancers (OGJC) are associated with poor survival. Evaluation of symptoms, monitoring of tumour markers, and spiral computed tomography (CT) can be used in postoperative surveillance to identify potential recurrence. 18FDG-PET-CT may be used when CT is equivocal despite positive clinical and biochemical markers, and may enable early diagnosis of recurrent disease. We hypothesise that 18FDG-PET-CT is superior to CT in identifying recurrent OGJC and may have a role in routine surveillance post-oesophago-gastrectomy. Methods Patients with recurrent OGJC after two-stage oesophago-gastrectomy performed in a single, tertiary, specialist UK cancer centre, who were investigated for suspected recurrence with 18FDG-PET-CT and CT within 1 month of each other, up to 5 years after primary resection were included. Demographic details including age, tumour staging (TNM classification), histological subtype, resection margin status, and serum CA19-9 and CEA levels at the time of recurrence were collected. Radiology reports were reviewed to determine whether recurrence was identified on CT, 18FDG-PET-CT or both. Statistical analyses were performed on the Datatab platform. Sensitivity of both imaging modalities at identifying recurrence was calculated. Results A total of n=65 (58 male, 7 female) patients were included. Locoregional, distant, and both locoregional and distant recurrence were identified in n=17 (26.2%), n=22 (33.8%) and n=26 (40.0%) patients respectively. 18FDG-PET-CT (63/65, 96.9% sensitivity) was superior to CT (57/63, 87.7% sensitivity) in detecting all recurrence (p=0.02) and distant recurrence (100% compared to 81.8% sensitivity). Eight patients had recurrence identified on 18FDG-PET-CT, but not by CT (n=4 distant recurrence, n=1 locoregional recurrence, n=3 distant and locoregional recurrence). Of n=5 patients who received treatment for recurrence, n=3 had single-site recurrence. Median survival following detection in this subgroup was 2 years. Conclusions This study demonstrated that 18FDG-PET-CT was significantly more sensitive than CT in detecting all recurrent OGJC, and distant recurrence. This modality may have a role in surveillance following oesophago-gastrectomy for OGJC. Its greater sensitivity may enable early diagnosis of recurrence when performed following identification of clinical or biochemical features suspicious for recurrent disease. This could enable appropriate patients to undergo further systemic anti-cancer therapy to treat recurrence, prevent further disease progression and improve survival. Further studies considering economic and logistical factors including availability of equipment to perform a higher volume of scans are required to support these findings.