Focal dose escalation in the treatment of prostate cancer. Long-term results of HDR brachytherapy

We prospectively examined the effect and the safety of intensity-modulated HDR brachytherapy (IMBT) with focal dose escalation. A total of 139 patients undergoing primary therapy for prostate cancer and 11 patients with recurrence were included. Data analysis focused on the following factors: date of primary diagnosis, Gleason score, initial prostate-specific antigen (PSA) value, PSA nadir, volume of the prostate in the transrectal ultrasound, biopsy of the prostate gland, androgen deprivation, chemotherapy, uroflowmetry, pre- and postoperative post-void residual urine (PVR), number of the needles in the prostate lobes and analysis of follow-up data. In the primary therapy group, 87.6 % of the patients had a PSA of 0-4 ng/ml at the time of follow-up, while in the recurrence group 81.8 % of patients were within this range. Overall, 55.8 % of patients in the primary group had a PSA nadir under 0.1 ng/ml, 37.2 % under 1 ng/ml, 5.8 % under 5 ng/ml and 1.2 % (1 patient) over 5 ng/ml. In the recurrence group, 100 % had a PSA nadir under 0.1 ng/dl. Fifty patients of the primary group reported grade 1 toxicity (Common Toxicity Criteria): 29 localized to the bladder and 21 to the rectum. Seventeen patients had grade 2 toxicity of the bladder and 1 patient had grade 3 toxicity of the bladder. Finally there was one grade 4 toxicity due to perforation of the sigmoid colon. In the recurrence group, 3 patients with grade 1 toxicity were observed (2 bladder and 1 bowl). Also 3 patients had grade 2 toxicity of the bladder, 1 patient had a grade 3 bladder toxicity and 1 patient had grade 4 toxicity due to bowl fistula. There were no grade 5 toxicities. The modifications of the "Kiel method" with focal dose escalation was proven as effective in locally advanced prostate carcinoma and in local recurrences of the disease with low level toxicity.