Metastatic bladder neoplasms treated with stereotactic body radiosurgery.

397 Background: Stereotactic Body Radiosurgery (SBR) as treatment for metastatic bladder cancer delivers high dose radiation precisely to the site of cancer. In our prospective data analysis, 20 sites of extravesical bladder cancer treated with SBR were analyzed. Methods: Twenty metastatic bladder neoplasms were treated in 15 patients. Sixteen were transitional cell carcinoma, 2 adenocarcinoma, 1 squamous cell carcinoma, and 1 rhabdomyosarcoma. Ages ranged from 39 to 82 years (mean 64) with 4 females and 11 males. Tumor volumes ranged from 10.2 to 563 cc (mean 129.8 cc). Patients were treated with 500-900 cGy (median 800) in 5-8 fractions (median 5) for a total dose of 3000-4500 cGy (median 4000). Cancers were radiographically evaluated with contrast CT and/or MRI studies and reviewed independently by radiologists. Disease control is defined as cessation of growth, shrinkage or disappearance of the tumor after treatment. Results: Follow-up ranged from 1 to 20 months (mean 8 months). The overall control rate was 90%. Both patients who did not respond to treatment were males with transitional cell carcinoma. By dose, volume, age, sex and prior treatment, there was no statistically significant difference in outcome among the 20 patients treated. Conclusions: SBR for metastatic bladder cancer offers a well-tolerated, non-invasive technique with a high rate of tumor control. Patients continue to be evaluated for longer follow up, possible benefits of local control and potential survival advantage. SBR remains an option for those whom standard approaches have not produced desired results or in patients seeking an alternative to surgical or chemotherapeutic treatment.