A probe is inserted into the rectum. High-intensity focused ultrasound (HIFU) energy using the Sonablate system is delivered to the prostate tissue over approximately 2 hours. Patients with residual cancer lesion (by biopsy), PSA greater than 0.5 ng/mL or increasing PSA levels taken 2 months apart, visible prostate tissue on ultrasound, and no local or distant metastases after day 90 undergo retreatment with HIFU.