Biochemical outcome after high-dose-rate intensity modulated brachytherapy with external beam radiotherapy: 12 years of experience

Study Type Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Biochemical control from series in which radical prostatectomy is performed for patients with unfavorable prostate cancer and/or low dose external beam radiation therapy are given remains suboptimal. The treatment regimen of HDR brachytherapy and external beam radiotherapy is a safe and very effective treatment for patients with high risk localized prostate cancer with excellent biochemical control and low toxicity. OBJECTIVE To investigate the long-term oncological outcome, during the PSA era, of patients with prostate cancer who were treated using high-dose-rate (HDR) brachy therapy (BT) combined with external beam radiation therapy (EBRT). PATIENTS AND METHODS From June 1998 to April 2007, 313 patients with localized prostate cancer were treated with 46 Gy of EBRT to the pelvis with a HDR-BT boost. The mean (median) follow-up was 71 (68) months. Toxicity was reported according to the Common Toxicity Criteria for Adverse Event, V.4. RESULTS The 10-year actuarial biochemical control was 100% for patients with no high-risk criteria, 88% for patients with two intermediate-risk criteria, 91% with one high-risk criterion and 79% for patients with two to three high-risk criteria (P= 0.004). The 10-year cancer-specific survival was 97% (standard deviation +/- 1%). The multivariate Cox regression analyses identified, Gleason score and T stage as independent prognostic factors for biochemical failure. Gleason score was the only factor to significantly affect distant metastases. Grade =3 late toxicity was not detected. CONCLUSION The 10-year results confirm the feasibility and effectiveness of EBRT with conformal HDR-BT boost for patients with localised prostate cancer.