83 Background: We present the long-term results of a cohort of patients with intermediate-risk prostate cancer (PC) treated with single fraction high-dose-rate brachytherapy (HDRB) combined with hypofractionated external beam radiation therapy (HRT). Methods: Patients with intermediate-risk PC were treated exclusively with HDRB and HRT. HDRB delivered a dose of 10 Gy to the prostate gland and HRT consisted of 50 Gy delivered in 20 daily fractions. The planning target volume was the prostate gland with a 1 cm margin all around. The first 121 consecutive patients with a minimum of 2 years post-treatment follow-up were assessed for acute and chronic toxicity and disease control. Results: The median follow-up was 62.8 months. No acute grade III or higher toxicities were seen. Grade II late GI toxicity was seen in 9 patients (7.4%) and grade III in 2 (1.6%). Grade 3 GU toxicity was seen in 2 patients (1.6%), both with urinary obstructive symptoms requiring catheterization. A repeat biopsy was offered to the first 58 consecutively treated patients, and 44 patients agreed with the procedure. A negative biopsy was found in 40 patients (91%). The biochemical relapse-free survival rate at 5 and 8 years were 90.7% and 81.4%, with 13 patients presenting biochemical failure. Among them, nine were diagnosed with distant metastasis. Prostate cancer-specific and overall survival rates at 8 years were 100% and 95.5%, respectively. Conclusions: Our program of HDRB and HRT is well tolerated, with acceptable toxicity rates. Furthermore, results from re-biopsies revealed an elevated rate of local control. These results are encouraging and confirm that the use of conformal RT techniques, adapted to specific biological features, have the potential to improve the therapeutic ratio in intermediate risk PC patients. No significant financial relationships to disclose.
Combination external beam radiation and brachytherapy boost with androgen deprivation for treatment of intermediate-risk prostate cancer
