HDR brachytherapy combined with hypofractionated EBRT for intermediate-high risk prostate cancer

Abstract

14655 Background: To report on biochemical outcome and late complication in pts with localized prostate cancer (LPC) treated with HDR-brachytherapy (HDR-BT) combined with hypofractionated EBRT. Methods: From 06/2000 to 12/2004, 108 pts with intermediate (37 pts.) or high-risk (63 pts.) LPC were treated with hypofractionated EBRT (3 Gy × 17 fr., thrice a week) followed by HDR-BT (5 Gy × 5; 9 pts, 7 Gy × 3; 15 pts, 9 Gy × 2; 76 pts). HDR-BT was administered a week after the completion of the hypofractionated EBRT. The planning target volume was defined as the prostate gland with a 5-mm margin all around, and the planning was conducted based on CT images. Biologically effective doses (BED) to the prostate was between 83–84 Gy. All patient received androgen ablation. Acute and late toxicities were scored according to the EORTC/RTOG morbidity grading scales. Median follow-up duration was 27 months from HDR-BT and 39 months from initiation of androgen ablation. Results: All pts completed treatment. The 5-year actuarial PSA relapse-free survival rates for intermediate and high-risk pts were 100% and 93% respectively. Acute genitourinary (GU) toxicity was 64% in grade 0–1, 31% in grade 2 and 6% in grade 3. Urethral stricture developed in 3%, with a median time from the completion of HDR brachytherapy to the occurrence of 22 months (19–26 months). Ten pts had grade 2 rectal bleeding, with a median time from the completion of HDR brachytherapy to the occurrence of 11 months (7–14 months). No pts developed grade 3 or more severe rectal complication. The incidence of acute and late toxicity did not differ according to the fractionation schema of HDR-BT. Conclusion: Our data demonstrate the successful feasibility of HDR-BT combined with hypofractionated EBRT as a safe method for escalating the total dose to the prostate without significant increasing risk of acute and late GU and rectal toxicities. No significant financial relationships to disclose.