1254 Examining the Role of PET-CT in the Management of Oesophageal Cancer: A Single Institution Experience

Abstract

Abstract Aim The role of PET-CT in oesophageal cancer is controversial. The aim of this study was to evaluate the utility of PET-CT in staging and response evaluation in oesophageal squamous cell carcinoma (SCC) and adenocarcinoma (AC). Method Patients undergoing curative-intent treatment were studied prospectively. PET1 was carried out at diagnosis and repeat scanning (PET2) was performed 2-4 weeks post-completion of neoadjuvant chemotherapy (nCT) or chemoradiation (nCRT). The association between PET parameters, histopathologic response and survival was determined using univariable and multivariable regression models. Results 730 consecutive patients were studied. PET identified CT-occult M1 disease in 2.9% and synchronous neoplasm in 1.4%. Similar PET1 SUVmax values were observed in AC and SCC. The reduction in SUVmax was greater post-nCRT versus nCT (P = 0.021). SUVmax correlated with pT stage among patients treated with primary surgery (P<0.001), however 32.3% with AC and 15.8% with SCC who were predicted node negative were pN+. Post neoadjuvant therapy, PET parameters showed modest associations with major pathologic response, but no parameter accurately predicted complete pathologic response. Among patients with a metabolic complete response (mCR), 90.9% with AC post-nCT, 84.1% with AC post-nCRT and 54.8% with SCC post-nCRT had residual disease. Lower preoperative SUVmax was independently associated with improved survival outcomes in AC, but not SCC. Conclusions PET-CT identified CT-occult M1 disease or synchronous neoplasms in 4.3% at initial staging. After neoadjuvant therapy, PET is poorly predictive of histopathologic response – most patients with an mCR have residual disease. Nonetheless, improvements in SUVmax may reflect a more favourable long-term outcome in AC.