Relation of tumor vascularity to effect of gemcitabine in pancreatic carcinomas: Value of contrast-enhanced harmonic ultrasonography

4114 Background: Most ductal adenocarcinomas of the pancreas are hypovascular as compared with the surrounding parenchyma on dynamic CT. Coded phase-inversion harmonic ultrasonography more clearly depicts fine vessels in pancreatic tumors after the infusion of ultrasound contrast than dynamic CT. In the present study, we observed the vascularity of pancreatic tumors by means of this technique and investigated its usefulness for evaluation of response to gemcitabine. Methods: Thirty-three patients with inoperable pancreatic carcinomas were enrolled in this study. They received gemcitabine (1 g/m2) 3 times in a cycle (4 weeks). Contrast-enhanced harmonic ultrasonography (CE-US) was performed immediately before the fist cycle and after completing each cycle, by the use of a GE LOGIQ 9 Series unit. We classified patients into 2 groups according to the changes of tumor vascularity observed by CE-US. Group A represents those with tumors in which tumor vascularity was increased during a certain period after the chemotherapy. Group B represents those with tumors in which tumor vascularity was not increased throughout the observation period. Tumor makers (serum CEA, CA19–9, Span-1 and Dupan-2) and median survival time (MST) were employed for the evaluation of therapeutic response and compared between the 2 groups. Results: CE-US demonstrated the increase of tumor vascularity after the chemotherapy in 17 of 33 patients (Group A). MST in the Group A (306 days) was significantly longer than that in the Group B (187 days). The reduction of tumor makers (reduction by 50 % of either serum CEA, CA19–9, Span-1 or Dupan-2) was observed in all patients (17/17) in the group A and in 25 % of patients (4/16) in the group B. The increase of tumor vascularity was noted when the tumor makers were reduced. The increased vascularity turned to decline in parallel with the tumor progression. Conclusion: CE-US is useful for the evaluation of chemotherapeutic response in terms of vascularity. The increased vascularity in pancreatic carcinomas after the chemotherapy may represent the improvement of vascular sclerosis and tumor invasion in small arterioles. No significant financial relationships to disclose.