External-Beam Radiation Therapy and High-Dose Rate Brachytherapy Combined With Long-Term Androgen Deprivation Therapy in High and Very High Prostate Cancer: Preliminary Data on Clinical Outcome

Purpose: To determine the feasibility of combined long-term androgen deprivation therapy (ADT) and dose escalation with high-dose-rate (HDR) brachytherapy. Methods and Materials: Between 2001 and 2007, 200 patients with high-risk prostate cancer (32.5%) or very high-risk prostate cancer (67.5%) were prospectively enrolled in this Phase II trial. Tumor characteristics included a median pretreatment prostate-specific antigen of 15.2 ng/mL, a clinical stage of T2c, and a Gleason score of 7. Treatment consisted of 54 Gy of external irradiation (three-dimensional conformal radiotherapy [3DCRT]) followed by 19 Gy of HDR brachytherapy in four twice-daily treatments. ADT started 0-3 months before 3DCRT and continued for 2 years. Results: One hundred and ninety patients (95%) received 2 years of ADT. After a median follow-up of 3.7 years (range, 2-9), late Grade >= 2 urinary toxicity was observed in 18% of the patients and Grade >= 3 was observed in 5%. Prior transurethral resection of the prostate (p = 0.013) and bladder D-50 >= 1.19 Gy (p = 0.014) were associated with increased Grade >= 2 urinary complications; age >= 70 (p = 0.05) was associated with Grade >= 3 urinary complications. Late Grade >= 2 gastrointestinal toxicity was observed in 9% of the patients and Grade >= 3 in 1.5%. CTV size >= 35.8 cc (p = 0.007) and D-100 >= 3.05 Gy (p = 0.01) were significant for increased Grade >= 2 complications. The 5-year and 9-year biochemical relapse-free survival (nadir + 2) rates were 85.1% and 75.7%, respectively. Patients with Gleason score of 7-10 had a decreased biochemical relapse-free survival (p = 0.007). Conclusions: Intermediate-term results at the 5-year time point indicate a favorable outcome without an increase in the rate of late complications. (C) 2012 Elsevier Inc.