Postlumpectomy loco-regional breast cancer therapy with liposomal therapeutic agents: Retention and distribution in nude rats

e11562 Background: Post-lumpectomy loco-regional radiation therapy, such as brachytherapy, has been shown to decrease breast cancer recurrence and increase patient survival. Limitations of current brachytherapy are the relatively high radiation absorbed dose delivered to normal breast and the inability to treat potentially involved lymph nodes. Locally administered liposomes are being investigated for delivery of drugs and therapeutic radionuclides. We propose a new post-lumpectomy loco-regional therapy with liposome-carried therapeutic agents. To investigate, radiolabeled liposomes were injected into the surgical cavity of a nude rat model one day following surgical removal of the breast tumor, and in vivo retention and distribution were monitored with nuclear imaging and post- mortem dissection. Methods: Six liposome formulations containing 0.2% molar ratio Rhodamine B-lipid and cationic, neutral, or anionic surface charges were manufactured at diameters of 400 or 100 nm and characterized. Breast cancer...