Treatment of Fluorouracil-Refractory Patients With Liver Metastases From Colorectal Cancer by Using Yttrium-90 Resin Microspheres Plus Concomitant Systemic Irinotecan Chemotherapy

Purpose Liver metastases are the principal cause of death in patients with advanced colorectal cancer (CRC). Irinotecan is a chemotherapeutic agent used in the treatment of CRC and has demonstrated synergistic potential when used with radiation. Radioembolization with yttrium-90 microspheres has demonstrated increased response and survival rates when given with fluorouracil chemotherapy. This study's goal was to evaluate the maximum-tolerated dose of concomitant irinotecan and radioembolization in fluorouracil-refractory patients with CRC hepatic metastases. Patients and Methods Twenty-five irinotecan-nave patients who had experienced relapse after previous chemotherapy were enrolled onto three dose-escalating groups. Irinotecan was administered at 50, 75, or 100 mg/m(2) on days 1 and 8 of a 3-week cycle for the first two cycles, and full irinotecan doses (ie, 100 mg/m(2)) were administered during cycles 3 to 9. Radioembolization was administered during the first chemotherapy cycle. Results Most patients experienced acute, self-limiting abdominal pain and nausea. Mild lethargy and anorexia were common. Grades 3 to 4 events were seen in three of six patients at 50 mg/m(2) (obstructive jaundice, thrombocytopenia, diarrhea), in five of 13 patients at 75 mg/m(2) (neutropenia, leukopenia, thrombocytopenia, elevated alkaline phosphatase, abdominal pain, ascites, fatigue) and in four of six patients at 100 mg/m(2) (diarrhea, deep vein thrombosis, constipation, leukopenia). Eleven (48%) of 23 patients had a partial response, and nine patients (39%) had stable disease. The median progression-free survival was 6.0 months; the median survival was 12.2 months. Conclusion Concomitant use of radioembolization plus irinotecan did not reach a maximum-tolerated dose. The recommended dose of irinotecan in this setting is 100 mg/m(2) on days 1 and 8 of a 3-week cycle.