Role of pre-operative F-18 FDG PET/CT as a predictor of recurrence in patients with ampulla of Vater cancer.

1376 Objectives: To explore the impact of PET parameters for the prediction of recurrence in patients diagnosed with resectable ampulla of Vater (AOV) cancer. Methods: A total of 41 AOV cancer patients, who underwent F-18 FDG PET/CT before curative surgery from 2009 to 2017 were enrolled (26 males, 15 females; mean age: 64.2, age range 42-82 years) We reviewed medical records of those patients and the following data were collected: demographic factors including age, sex, pathologic characteristics of the primary tumor (such as pathologic T and N stage, differentiation, presence of lymphatic and vascular invasion) and pre-operative carbohydrate antigen 19-9 level. We measured the following PET parameters for the primary tumor: maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV2.5) using threshold SUV 2.5, total lesion glycolysis (TLG) and tumor to liver SUV ratio (TLR). The Cox proportional hazard model was used for univariate and multivariate analysis to test the influence of clinic-pathologic factors and PET parameters on recurrence. Results: 24 patients (58.5%) had recurrence during follow-up period. Median disease-free survival was 16.6 months. On univariate analysis, tumor size, T stage, presence of vascular invasion, MTV2.5, and TLG were significant prognostic factors of recurrence after surgery. Among these factors, the presence of vascular invasion (hazard ratio [HR] 4.416, 95% confidence interval [CI] 1.71-11.4, P = 0.002) and MTV2.5 (HR 1.179, 95% CI 1.079-1.29, P < 0.001) were independent prognostic factors of recurrence on multivariate analysis. Conclusions: Higher MTV2.5 and presence of vascular invasion may be associated with recurrence of patients with resectable AOV cancer.