Enhancements in pancreatic protocol CT as a prognostic indicator in pancreatic cancer.

Abstract

216 Background: Pancreatic protocol CT (pCT) is widely used to evaluate stage and resectability of pancreatic ductal adenocarcinoma (PDAC). Recent studies show that CT enhancement patterns are related to the patient’s prognosis in several cancers, however it is not well described that pCT enhancement has prognostic effect in resectable PDAC so far. We aimed to show correlaton between pCT enhancements and prognosis in resectable PDAC. Methods: We retrospectively enrolled 159 patients (median age, 67.8 years) who underwent pCT before curative resection in Seoul National University Bundang Hospital between January 2010 and December 2015, with final pathological diagnosis of PDAC. CT enhancement ratio (CTER) of each primary lesion was calculated as proportional difference between maximum Houndsfield Unit (HU) of pancreatic phase (PP) image and maximum HU of non-contrast image; [(max HU of PP) - (max HU of non-contrast)] / (max HU of non-contrast). Patients were classified into two groups, based on CTER. Kaplan–Meier analysis and Cox proportional hazards models were used to correlate CTER with overall survival (OS) and recurrence free survival (RFS). Results: Median overall survival was 22.0 months during a median follow-up period of 18.5 months. Based on CTER with cut-off value of 1.8, higher (CTER ≥ 1.8) group (N = 43) was compared with lower (CTER < 1.8) group (N = 116) in terms of OS and RFS. Lower group showed significantly shorter median OS (18.5 months versus 39.3 months, P < 0.001) and median RFS (9.9 months versus 21.5 months, P = 0.006) than those of higher group. Multivariate regression analysis showed that lower group had shorter OS (HR 1.70; CI 1.01-2.85, P = 0.044) and RFS (HR 1.84; CI 1.10-3.06, P = 0.019). Conclusions: Our study suggests that lower enhancement in pancreatic phase of pCT is related to poor prognosis in PDAC. Therefore, active surveillance would be required in resected PDAC patients with CTER less than 1.8.