10581 Background: Hepatic intra-arterial chemotherapy has been reported to produce higher response rate than systemic in patients (pts) with metastatic colorectal cancer. In breast cancer the liver is involved in up to 60% of cases and often conditions the prognosis. Nevertheless, only rare hepatic arterial infusion studies were published. Therefore, based on our previous experience in hepatic metastatic colorectal malignancies, we evaluated efficacy and toxicity of hepatic intra-arterial chemotherapy in pts with metastatic breast cancer. Methods: A three-day continuous arterial infusion (CAI) of fluorouracil 1000 mg/m2 q 24 hrs, with cisplatin 10 mg/m2 twice daily, and mitomycin-c 1 mg/m2 twice daily, was performed through a percutaneous radiological temporary trans-subclavicular catheter. Pts with responsive disease received up to four cycles every six weeks. Pts still responding could carry on with cisplatin and fluorouracil, without mitomycin-c. Pts were hospitalized and the catheter was removed upon end of infusion. Results: From 9.2000 to 6.2005, 25 pts with progressive liver metastases from breast cancer were treated. Nine had more than 50% of liver involvement. Fifteen had also extra-hepatic metastases. All had received antracyclines and 22/25 taxanes. Pts had a median of five previous chemotherapy lines. Median time from diagnosis of liver metastases to first CAI was 33 months (range: 7–110). Sixty-four total courses were administered, with a median of 2 (range: 1–7) per pts. Epigastric pain was the main clinical toxicity (54%) and iatrogenic gastro-duodenal ulcer, the main complication (28%). No relevant catheter-related complications occurred. Fifteen partial responses (60%) and eight stable diseases (32%) were observed. Response duration was 5.4 months (range: 2 - 27), time to progression 5.1 months (range: 2.5–29+), and median overall survival 13 months (range: 3.5+–32+). Conclusions: Hepatic arterial infusion of chemotherapy in heavily pre-treated pts with metastatic breast cancer is feasible and effective. A specific evaluation of quality of life should be performed to verify a real clinical benefit. An earlier timing during course of liver disease, and a shift to radiological implanted arterial port (allowing out-patient treatment), will be investigated. No significant financial relationships to disclose.