Chemotherapy with Yttrium 90 Microsphere Selective Internal Radiation Treatment and Selective External Radiation Treatment in Patients with Metastatic Pancreatic Cancer.

Background: Pancreatic cancer remains a disease with a poor prognosis. Historically, response rates to chemotherapy alone remain low, and response duration lasts only months, with no clear improvement in survival. This study compiled the data from a pilot phase II trial and a retrospective review of cases with a treatment protocol involving combined use of selective internal radiation therapy (SIRT) using yttrium 90 (90Y) resin microspheres directed to hepatic metastases, selective external radiation treatment (SERT) using TomoTherapy (TomoTherapy Inc., Madison, WI) directed to pancreatic bed disease, and 5-fluorouracil infusional chemotherapy adminstered to patients with metastatic pancreatic cancer. Methods: The study population consisted of patients with pancreatic cancer metastatic to the liver, with or without pancreatic bed disease. Those with liver and pancreatic bed disease were offered the chemotherapy-SIRT-SERT complete protocol, whereas those with liver-only disease were eligible for the chemotherapy-SIRT combination. Patients underwent visceral angiography, technetium 99m macroaggregated albumin scanning, and pancreatic protocol fluorine 18 fluorodeoxyglucose- positron emission-computed tomography (PET-CT) scan. Determinations of the administered activity resulting from 90Y microsphere SIRT were made based on dosimetric calculations using medical internal radiation dosimetry. In the delivery of SERT, the target volume was composed of the pancreatic tumor and any positive lymph nodes and specifically excluded the liver metastasis. Objective response measures included the CA 19.9 level for the evaluation of overall disease status and PETCT- based determinations of standard uptake volume (SUV), functional tumor volume (FTV), total lesion glycolysis (TLG), and anatomic tumor volume. Results: Seven patients had both liver and pancreatic bed disease and received the complete chemotherapy-SIRT-SERT protocol and four patients received chemotherapy-SIRT for liver-only disease. In the chemotherapy-SIRT-treated field, seven of the nine patients demonstrated a decrease in SUV avg and six patients showed a decrease in FTV and TLG. In the chemotherapy- SERT-treated field, six of the seven patients who received TomoTherapy demonstrated a decrease in SUV avg , five patients showed a decrease in FTV, and six patients demonstrated a decrease in TLG. Disease progression was observed in four patients with extrapancreaticohepatic lesions not covered with SIRT or SERT. [ABSTRACT FROM AUTHOR]