Mesenteric Vessel Patency Following HIFU Therapy in Patients with Locally Invasive Pancreatic Cancer.

PURPOSE:  To evaluate the effects of HIFU therapy on visceral vessel patency in patients with inoperable locally invasive pancreatic cancer.

MATERIALS AND METHODS:  50 pancreatic cancer patients (26 men, 24 women) aged 41 - 82 years (65.0 ± 10.2) underwent ultrasonography (US) and computed tomography (CT) examinations before and within one day after HIFU treatment, as well as at follow-up at six weeks, three months and six months. Evaluation and grading were performed by two experienced independent radiologists according to a classification scheme based on vessel involvement, vessel diameter, patency, and defects in flow.

RESULTS:  Before HIFU treatment, arterial vessel involvement was noted in 42 patients, venous involvement in 47, and 47 patients presented with both. Superior mesenteric artery occlusion was found in three carcinomas while nearly half of the cases (n = 24) displayed signs of superior mesenteric vein, portal vein, or splenic vein occlusion. High-grade tumor-associated arterial narrowing was seen in ten patients. Despite vessel encasement and partially extensive propagation of collateral vessels, it was possible to safely perform HIFU treatment in all patients without complications. US and CT studies performed within one day after therapy did not show any change in vessel patency in 47 patients (94 %). Follow-up controls at the six-week mark revealed increased vessel narrowing and finally occlusion after six months in 11 patients due to tumor progression.

CONCLUSION:  This study demonstrates that HIFU treatment can be safely applied to pancreatic cancers enveloping large mesenteric vessels despite vessel narrowing or extensive collateral propagation. Most patients (94 %) did not experience adverse effects regarding vessel patency.