Objective: Stereotactic Body Radiation Therapy (SBRT) offers definitive treatment for localized prostate cancer with comparable efficacy and toxicity to conventionally fractionated radiotherapy.   Decreasing the number of treatment visits from over forty to five may reduce finical burden and improve quality of life (QOL). The purpose of this study is to assess financial toxicity following SBRT for prostate cancer.  
 
Methods: Financial toxicity was assessed using the 11-item COST-Functional Assessment of Chronic Illness Therapy questionnaire.  COST scores range from 0 - 44 with lower values representing higher financial burden.  Financial toxicity was graded using a previously described scale1: Grade 0 (score > 26, no effect on QOL), Grade 1 (score 14-25, mild effect on QOL), Grade 2 (score 1-13, moderate effect on QOL), and Grade 3 (score 0, high effect on QOL).
 
Results: From 2019 to 2021, we prospectively assessed the financial burden of 301 prostate cancer patients with a median age of 72 years (range 49-91yo). 301 patients completed the questionnaire.  The patients were ethnically diverse with 32.9% being of African American decent.  > 95% of the patients were insured.  82.7% experienced no financial toxicity. Grade 1 and Grade 2 toxicity occurred in 15.0% and 2.3%, respectively; there were no grade 3 toxicities.
 
Conclusion: SBRT is an effective and convenient treatment for prostate cancer.  The incidence of high-grade financial toxicity was low following this standard of care treatment. Future studies should assess how financial burden compares following treatment with other radiation modalities.