Purpose: To report prostate-specific antigen (PSA) relapse-free survival and treatment-related toxicity outcomes after combining high-dose-rate (HDR) brachytherapy with external beam radiotherapy (EBRT) for patients with clinically localized prostate cancer. Methods and Materials: Between 1998 and 2009, 229 patients were treated with HDR brachytherapy followed 3 weeks later by supplemental EBRT. The HDR brachytherapy boost consisted of three fractions of192Ir (5.5-7.5Gy per fraction), and EBRT consisted of intensity-modulated radiotherapy delivering an additional 45.0-50.4Gy directed to the prostate gland and seminal vesicles. Median follow-up was 61 months. Results: Seven-year PSA relapse-free survival for low-, intermediate-, and high-risk patients were 95%, 90%, and 57%, respectively (p< 0.001). Among high-risk patients treated with biological equivalent doses in excess of 190. Gy, 7-year PSA relapse-free survival was 81%. In multivariate analysis, Gleason scores of ≥8 predicted for increased risk of biochemical failure, whereas the use of short-term neoadjuvant androgen deprivation therapy did not influence tumor-control outcomes even among intermediate- or high-risk patients. Seven-year incidence of distant metastases for low-, intermediate-, and high-risk patients were 5%, 3%, and 17%, respectively. Seven-year incidence of late Grade 2 and 3 genitourinary toxicities were 22.1% and 4.9%, respectively and the 7-year incidence of Grade 2 and 3 gastrointestinal toxicities were 1% and 0.4%, respectively. Conclusion: HDR prostate brachytherapy in conjunction with supplemental EBRT results in excellent biochemical relapse-free survival rates with a low incidence of severe late genitourinary or gastrointestinal toxicities. The use of short-term neoadjuvant androgen deprivation did not influence long-term biochemical tumor control in this cohort. © 2013.
Kotecha, R., Yamada, Y., Pei, X., Kollmeier, M. A., Cox, B., Cohen, G. N., … Zelefsky, M. J. (2013). Clinical outcomes of high-dose-rate brachytherapy and external beam radiotherapy in the management of clinically localized prostate cancer. Brachytherapy, 12(1), 44–49. https://doi.org/10.1016/j.brachy.2012.05.003