Curative-intent stereotactic body radiation therapy for residual breast cancer liver metastasis after systemic chemotherapy.

Liver metastases from breast cancer are generally treated with systemic therapy such as chemotherapy or hormonotherapy. However, local treatment options such as resection, radiofrequency ablation (RFA), and radiotherapy can also be considered to treat oligometastases. We report the case of a 45-year-old female treated with stereotactic body radiotherapy (SBRT) after chemotherapy against a solitary liver metastasis from primary breast cancer. A liver metastasis with diameter of 35 mm developed 3.5 years after surgery for primary breast cancer in 2004. Fourteen courses of triweekly docetaxel treatments considerably decreased the metastatic lesion, but there still remained a tiny lesion radiographically. Chemotherapy was stopped because of the side-effects of docetaxel, and then SBRT was selected for additional treatment, aiming at complete cure of metastasis. X-ray irradiation (52.8 Gy/4 fractions) was applied to the remaining metastatic lesion, and magnetic resonance imaging (MRI) showed no evidence of residual tumor 4 months after irradiation. Neither regrowth nor recurrences have been found until now, 24 months after SBRT. SBRT for oligometastases of breast cancer may be one of the possible curative-intent options, being less invasive than surgical resection or RFA.