Combined treatment image guided-intensity modulated radiotherapy (IG-IMRT) plus high-dose rate brachytherapy (HDR) and hormonotherapy (HT) as treatment for high-risk prostate cancer: Five-year result of a phase II study

Abstract

15571 Background: To report early and late toxicity and preliminary biochemical outcome in 345 patients with high-risk (Gleason >=7; PSA>20 or T2c-T3) clinically localized prostate cancer treated with combined high-dose-rate brachytherapy and IMRT (IMRT-HDR) to the prostate and seminal vesicles with 24–36 months of hormononal treatment (goserelin+bicalutamide) (HT). Methods: Between 12/1999 and 10/2003, 345 patients with PSA>20, Gleason score>6 and/or T2c-T3 N0 M0 prostate cancer were treated with IG-IMRT followed by HDR implant to the prostate and HT. Patients were randomly assigned to receive HT for 24 (group 1, 172 patients) or 36 months (group 2, 173 patients). Acute and late toxicities were scored by the EORTC/RTOG morbidity grading scales. Special attention to local, regional or distant recurrence, survival, late effects, PSA and testosterone levels and quality of life was done. PSA failure was defined as nadir +2.0 ng/ml. Results: All patients completed treatment. One patient included in the group 1 and none of the group 2 experienced grade 3 rectal toxicity (rectal ulcer). Seven patients in each group (4.0%) developed acute Grade 2 urinary symptoms, and none experienced urinary retention. No patient (0%) developed Grade 4 rectal complications or grade 3 or 4 urinary complications. With a median follow-up of 44 months, the 5-year actuarial PSA relapse-free survival rates for the whole group of patients was 95.7 %. No statistical differences between group 1 and 2 patients were found. Conclusions: High-dose IG-IMRT+HDR and HT was a safe and effective method of escalating the dose to the prostate without increasing the risk of late effects. Acute and late rectal and urinary complications were significantly low, compared with what has been observed with high-dose conventional, 3D-conformal or IMRT-only. Short-term PSA control rates seem to be at least comparable to those achieved with 3D-EBRT or IMRT. Both treatment regimes were very effective. Longer follow-up is needed to know if better PSA control rate are achieved with longer HT. No significant financial relationships to disclose.