Tumor Aggressiveness and Patient Outcome in Cancer of the Pancreas Assessed by Dynamic ¹⁸F-FDG PET/CT

Abstract

This study aimed to assess the role of a quantitative dynamic PET model in pancreatic cancer as a potential index of tumor aggressiveness and predictor of survival. Methods: Seventy-one patients with ¹⁸F-FDG–avid adenocarcinoma of the pancreas before treatment were recruited, including 27 with localized tumors (11 underwent pancreatectomy, and 16 had localized nonresectable tumors) and 44 with metastatic disease. Dynamic ¹⁸F-FDG PET images were acquired over a 60-min period, followed by a whole-body PET/CT study. Quantitative data measurements were based on a 2-compartment model, and the following variables were calculated: VB (fractional blood volume in target area), K₁ and k₂ (kinetic membrane transport parameters), k₃ and k₄ (intracellular ¹⁸F-FDG phosphorylation and dephosphorylation parameters, respectively), and ¹⁸F-FDG INF (global ¹⁸F-FDG influx). Results: The single significant variable for overall survival (OS) in patients with localized disease was ¹⁸F-FDG INF. Patients with a high ¹⁸F-FDG INF (>0.033 min⁻¹) had a median OS of 6 and 5 mo for nonresectable and resected tumors, respectively, versus 15 and 19 mo for a low ¹⁸F-FDG INF in nonresectable and resected tumors, respectively (P < 0.04). In metastatic disease, multivariate analysis found VB, K₁, and k₃ to be significant variables for OS (P < 0.043, <0.031, and <0.009, respectively). Prognostic factors for OS in the entire group of patients that were significant at multivariate analysis were stage of disease, VB, K₁, and ¹⁸F-FDG INF (P < 0.00035, <0.03, <0.024, and <0.008, respectively). Median OS for all patients with a high ¹⁸F-FDG INF, low VB, and high K₁ was 3 mo, as opposed to 14 mo in patients with a low ¹⁸F-FDG INF, high VB, and low K₁ (P < 0.021), irrespective of stage and resectability. Conclusion: Quantitative ¹⁸F-FDG kinetic parameters measured by dynamic PET in newly diagnosed pancreatic cancer correlated with the aggressiveness of disease. The ¹⁸F-FDG INF was the single most significant variable for OS in patients with localized disease, whether resectable or not.