Scoring system predictive of survival for patients undergoing stereotactic body radiation therapy for liver tumors
Department of Radiation Oncolog, Georgetown University Hospital, Lower Level Bles, 3800 Reservoir Road, Georgetown, N.W. Washington, D.C., 20007, USA
Radiation Oncology 2012, 7:148 doi:10.1186/1748-717X-7-148Published: 5 September 2012
Stereotactic body radiation therapy (SBRT) is an emerging treatment option for liver tumors. This study evaluated outcomes after SBRT to identify prognostic variables and to develop a novel scoring system predictive of survival.
The medical records of 52 patients with a total of 85 liver lesions treated with SBRT from 2003 to 2010 were retrospectively reviewed. Twenty-four patients had 1 lesion; 27 had 2 or more. Thirteen lesions were primary tumors; 72 were metastases. Fiducials were placed in all patients prior to SBRT. The median prescribed dose was 30 Gy (range, 16 – 50 Gy) in a median of 3 fractions (range, 1–5).
With median follow-up of 11.3 months, median overall survival (OS) was 12.5 months, and 1 year OS was 50.8%. In 42 patients with radiographic follow up, 1 year local control was 74.8%. On univariate analysis, number of lesions (p = 0.0243) and active extralesional disease (p < 0.0001) were predictive of OS; Karnofsky Performance Status (KPS) approached statistical significance (p = 0.0606). A scoring system for predicting survival was developed by allocating 1 point for each of the three following factors: active extralesional disease, 2 or more lesions, and KPS ≤ 80%. Score was associated with OS (p < 0.0001). For scores of 0, 1, 2 and 3, median survival intervals were 34, 12.5, 7.6, and 2.8 months, respectively.
SBRT offers a safe and feasible treatment option for liver tumors. A prognostic scoring system based on the number of liver lesions, activity of extralesional disease, and KPS predicts survival following SBRT and can be used as a guide for prospective validation and ultimately for treatment decision-making.