Extracranial metastases treated with body stereotactic radiosurgery (BSR)

Purpose/Objective: Body Stereotactic Radiosurgery (BSR) is a novel treatment that allows for stereotactically guided linear accelerator based hypofractionated radiation, using a non-invasive external fiducial fixation system. The purpose of BSR for extra-cranial metastases is to control sites of cancer in those often previously treated unsuccessfully by standard radiation, chemotherapy or surgery. Materials/Methods: 1363 metastatic cancers in 993 patients completed treatment between March 1997 and August 2001. 715 extracranial metastases with a volume range of 0.05 to 4951cc (mean 198.5cc) were radiographically evaluated before and sequentially after treatment in 520 patients (pts) aged 17 to 89 years (mean 61) by delivering a radiosurgery dose of 180 to 1000 Centigray (cGy) per fraction (mean 741). Three to 8 fractions (mean 5) were utilized. 39% of metastases were hepatic with 53% colonic origin and 8% pancreatic. 24% of metastases were pulmonary and originated from the kidney in 27% and colon in 22%. Radiographic follow-up ranges from 1 to 51 months (mean 7.7). Control is defined as cessation of growth, shrinkage or disappearance of the cancer in the involved field-as determined by follow-up contrast CT scanning. Results: The overall control rate was 82%. 48% of the metastases showed cessation of growth, 32% decreased in size and 2% disappeared. 18% of the metastases progressed in the treatment field. 76% of liver metastases and 85% of lung metastases were successfully controlled. Treatment was well tolerated despite the fact that the vast majority of patients were extensively heavily pre-treated with surgery, chemotherapy, and radiation. Conclusions: Data shows that BSR can be performed safely with a high degree of success even in pts having received extensive prior treatment. It is non-invasive, quickly completed and minimizes radiation to surrounding tissue. Continued evaluation is vital to confirm these early promising results. The appeal of this treatment is that it is performed as an outpatient and is highly effective in the targeted field. It should be considered in those with symptomatic metastasis or in those who have limited sites of disease.