Prostate Stereotactic Body Radiotherapy - First UK Experience

Aims: Stereotactic body radiotherapy (SBRT) combines image-guided radiotherapy with hypofractionation, both of which will probably result in improvements in patient outcomes in prostate cancer. Most clinical experience with this technique resides in North America. Here we present the first UK cohort to receive SBRT for prostate cancer. Materials and methods: Fifty-one prostate cancer patients (10 low risk, 35 intermediate risk and 6 high risk) were treated with 36.25Gy in five fractions over 1-2 weeks and gold seed image guidance. All patients had toxicity International Prostate Symptom score (IPSS) and Radiation Therapy Oncology Group) recorded prospectively and prostate-specific antigen was measured 3-6 monthly during follow-up. Results: The median IPSS was 6, 11, 8 and 5 at baseline, 1-3 weeks, 4-6 weeks and 7-12 weeks after treatment. Radiation Therapy Oncology Group genitourinary and gastrointestinal toxicity of grade 2 was seen in 22% and 14%, respectively, at 1-3 weeks after treatment; no patient had grade 3+ toxicity at this time point, although two patients had grade 3 urinary frequency recorded during treatment. The median follow-up for the 42 patients who did not receive androgen deprivation was 14.5 months. Prostate-specific antigen at 13-18 months after treatment was 1.3ng/ml. Conclusion: Prostate SBRT is a promising treatment for organ-confined prostate cancer and is currently being investigated in a UK-led phase III trial.