The course of treatment for my brother's prostate cancer is external beam radiation, and his doctor is confident about how successful this treatment is. Can external beam radiation cure prostate cancer?
yes
Very successful for early stage, Gleason 6 or lower and PSA <10. Good local control can be achieved if combined with hormonal therapy for high Gleason score (7- 10) and high PSA> 10.
This would be a question more for someone in radiation oncology. However, if there is no metastatic disease, it could be curative. The patient should be monitored with serial PSA testing.