Aim: External beam radiotherapy (EBRT) followed by high dose rate (HDR) brachytherapy boost has demonstrated minimal toxicities and improved disease control rate compared with EBRT alone in observational and randomized studies with predominantly Caucasian patients. This study aims to report the outcomes of patients treated with this approach in our predominantly Asian population.
Methods: Medical records for patients with localized prostate cancer who received combined EBRT delivered via intensity modulated radiotherapy (IMRT) technique followed by HDR brachytherapy boost were retrospectively reviewed. Outcomes evaluated included 5-year biochemical recurrence-free survival (per Phoenix definition), overall survival and treatment toxicities.
Results: From June 2009 to March 2015, 75 patients were treated with IMRT followed by HDR brachytherapy boost. Twenty patients (27%) had intermediate risk, 55 (74%) had high-risk disease. Median follow up was 64 months. All patients received IMRT to a median dose of 45 Gy to the pelvis followed by HDR brachytherapy boost. Sixty, 10 and 5 patients received boost of 21 Gy in two fractions, 19 Gy in two fractions and 15 Gy in a single fraction, respectively. All patients met the planning criteria adapted from RTOG 0815. The 5-year prostate-specific antigen (PSA) control was 85.2% (80.3% and 100% for high-risk and intermediate-risk group, respectively). Cancer-specific survival and overall survival are 97.3% and 92.0%, respectively. Eleven (15%) patients developed biochemical failure, six of which had distant metastasis. Three (4%) developed grade 3 genitourinary toxicity (urethral stricture and/or cystitis) and none developed grade 3 radiation proctitis.
Conclusion: Our outcomes are comparable to internationally published data and demonstrate reproducibility of this approach in our population.
Keywords: brachytherapy; high dose rate; intensity modulated radiotherapy; prostate cancer; radiotherapy.
© 2017 John Wiley & Sons Australia, Ltd.