Feasibility of Magnetic Resonance Imaging–guided Focused Ultrasound Surgery as an Adjunct to Tamoxifen Therapy in High-risk Surgical Patients with Breast Carcinoma

PURPOSE To evaluate the feasibility of treating breast neoplasms with use of magnetic resonance (MR) imaging–guided focused ultrasound (US) surgery. MATERIALS AND METHODS Twenty-four female patients, each with a single biopsy-proven breast carcinoma, who were considered to be at increased surgical risk or who had refused surgery underwent MR imaging–guided focused US surgery as an adjunct to their chemotherapeutic regimen of tamoxifen. Follow-up included routine studies to rule out metastatic disease and MR studies with and without contrast material infusion in the treated breast (10 days and 1, 3, and 6 months after the treatment session). Percutaneous biopsy was performed after 6-month follow-up, and if residual tumor was present, a second MR imaging–guided focused US surgery treatment session was performed, followed by repeat biopsy 1 month later. RESULTS Twenty-three of 24 patients completed the protocol, with only one minor complication associated with the treatment sessions (second-degree skin burn resolved with local treatment). Follow-up MR studies demonstrated a varying hypointense treatment margin (range, 1–11 mm), which represents destruction of tissue beyond the visible tumor. Absence of enhancement may be an indicator of tumor destruction (18 of 19 patients with negative biopsy results) whereas persistent enhancement suggested tumor residue (three of five patients with residual tumor). Overall, 19 of 24 patients (79%) had negative biopsy results after one or two treatment sessions. CONCLUSION MR imaging–guided focused US surgery of breast tumors is a safe, repeatable, and promising method of focal tumor destruction.