Objectives: This pilot study investigated the association of four PET image features and cyclo-oxygenase-2 (COX-2) expression in patients with oesophageal adenocarcinoma. The prognostic significance of these biomarkers was also assessed.
Methods: 50 consecutive patients [median age = 68 (range 47 - 84), males = 45) with oesophageal adenocarcinoma had PET/CT staging between January 2011 and July 2015. The maximum and mean standardised uptake values (SUVmax and SUVmean), metabolic tumour volume (MTV) and tumour lesion glycolysis (TLG) were calculated from the primary tumour. Their association with COX-2 status was assessed using Mann-Whitney U tests. Kaplan-Meier and Cox regression analysis tested their prognostic significance. A p-value < 0.05 was considered statistically significant.
Results: 32 tumours (64.0%) were COX-2 positive. There was a significant association between SUVmean and COX-2 status (p = 0.019). TLG (hazard ratio (HR) 1.001, 95 % confidence intervals (CI) 1.000 - 1.002, p = 0.018) was significantly associated with overall survival on multivariable analysis.
Conclusions: This study investigated the association between PET image features and COX-2 expression in oesophageal adenocarcinoma. The preliminary results signal that a combination of TLG (calculated as product of MTV and SUVmean) and COX-2 status may be a strong and clinically important prognostic biomarker. Our research group are planning a prospective, multi-centre study to validate these findings.
Advances in knowledge: Mean standardised uptake value (SUVmean) on PET imaging is associated with COX-2 expression in oesophageal adenocarcinoma.