66 Background: High dose rate (HDR) brachytherapy for prostate cancer is commonly given in multiple fractions combined with external beam radiotherapy (EBRT) over 5 weeks. We report results of a phase II clinical trial of single fraction HDR combined with hypofractionated EBRT over 3 weeks. Methods: Eligible patients had T1 or T2 carcinoma of the prostate with a PSA < 20 and Gleason score of 7 or less, without use of androgen deprivation. The trial accrued 125 patients with a median PSA of 6.8 ng/ml; 93% had Gleason 7. Single 15 Gy HDR was delivered to the prostate, followed 2-weeks later by EBRT to 37.5 Gy in 15 fractions. Patients were followed for toxicity (CTCAE v 3.0), health related quality of life (EPIC), urinary symptoms (IPSS), and clinical and biochemical control. Results: Median follow-up is 3 years (range: 1-4.5 years), with no biochemical failures. Median PSA at 3 years is 0.24 ng/ml. One of 38 biopsies at 2 years had persistent cancer. Two patients (1.6%) had acute grade 3 urinary toxicity, and median IPSS score returned to within 2 points of baseline by 3 months. The prevalence of grade 2 rectal and urinary toxicity at 2 years was 2% and 25%, respectively. Mean EPIC urinary and bowel domain scores decreased in the first 2 years, but returned to within 5 points of baseline at 3 years. Mean sexual function scores declined over the first 4 years although sexual bother scores returned to baseline at 3 years. On multivariate analysis, baseline IPSS score (p=0.0125), V100 (p=0.0002) and V200 (p=0.0141) were associated with acute grade 2 urinary toxicity. Decline in EPIC urinary quality of life domain was associated with HDR dose to 10% of urethra (p=0.0168), with a threshold of 120%. Decline in sexual scores was associated with smaller prostates and high baseline erectile functioning. Conclusions: Single fraction 15 Gy HDR combined with hypofractionated external beam radiotherapy is a well tolerated and effective treatment for intermediate risk prostate cancer. No significant financial relationships to disclose.
Five-year quality of life in patients with high-risk localized prostate cancer treated with external beam radiotherapy alone versus external beam radiotherapy with high-dose-rate brachytherapy boost: a prospective multicenter study
