18F-fluorodeoxyglucose PET/computed tomography and risk stratification after neoadjuvant treatment in esophageal cancer patients.

Objectives: The aim of the study was to evaluate the prognostic value of F-fluorodeoxyglucose PET/computed tomography (CT) after neoadjuvant therapy (NAT) in locally advanced esophageal cancer (EC) patients.

Materials And Methods: We recruited 79 EC patients from a sample of 210 who underwent F-fluorodeoxyglucose PET/CT after NAT and who did not have evidence or suspicion of distant metastases. All patients were followed up for a median period of 18 months (range: 2-53 months) from nuclear imaging. PET/CT findings were correlated with surgical management and long-term prognosis. The χ-test was used for categorical variables and the Student t-test for continuous data. Survival curves were computed using the Kaplan-Meier method. A P value less than 0.05 was considered statistically significant.

Results: Twenty patients (25.3%) had negative PET/CT and 59 (74.7%) had positive PET/CT results after NAT. Of the 20 patients with negative PET/CT results, eight underwent radical-intent surgery and 12 did not, whereas of the 59 patients with positive PET/CT 44 were scheduled for surgery and 15 were not (P<0.05). On follow-up, 38 patients were seen to be disease free, whereas 23 had relapsed and 15 had died. The overall survival was different between patients with negative PET/CT and those with positive PET/CT scans (98 vs. 40%; P=0.019). Event-free survival was higher in patients with negative PET/CT than in those with positive PET/CT after NAT (78 vs. 0%; P=0.003). Considering patients with positive PET/CT, in the nonsurgical group only three patients were alive without evidence of disease, whereas in the surgical group 19 patients were disease free (20 vs. 46%; P<0.001).

Conclusion: PET/CT is able to stratify the recurrence risk of EC patients. After a median follow-up period of 18 months, 91% of patients with negative PET/CT scans who did not undergo surgery were seen to be disease free. A positive PET/CT after NAT should be followed by surgery for improving event-free survival.