Purpose: To evaluate the feasibility and efficacy of hypofractionated stereotactic body radiation therapy (SBRT) for the treatment of liver metastases.
Methods and materials: The records of 69 patients with 174 metastatic liver lesions treated with SBRT between April 2001 and October 2004 were reviewed. The most common primary tumors were colorectal (n = 20), breast (n = 16), pancreas (n = 9), and lung (n = 5). The mean number of lesions treated per patient was 2.5 (range, 1-6). The longest diameter of the lesions ranged in size from 0.6 to 12.2 cm (median, 2.7 cm). Dose per fraction ranged from 2 Gy to 6 Gy, with a median total dose of 48 Gy (range, 30-55 Gy). Dose was prescribed to the 100% isodose line (IDL), with the 80% IDL covering the gross tumor volume with a minimum margin of 7 mm.
Results: The median follow up was 14.5 months. Sixty patients were evaluable for response based on an abdominal computed tomography scan obtained at a minimum of 3 months after completion of SBRT. The actuarial overall infield local control rate of the irradiated lesions was 76% and 57% at 10 and 20 months, respectively. The median overall survival time was 14.5 months. The progression-free survival rate was 46% and 24% at 6 and 12 months, respectively. None of the patients developed Grade 3 or higher toxicity.
Conclusion: Hypofractionated SBRT provides excellent local control with minimal side effects in selected patients with limited hepatic metastases.