High-Dose-Rate Brachytherapy Combined With External Beam Radiotherapy for Localized Prostate Cancer: Clinical Predictive Factor for Biochemical Relapse-Free Survival

Abstract

Purpose: The aim of this study is to determine what kind of clinical factors were predictive for biochemical relapse-free survival (bRFS) of prostate cancer (CaP) patients treated with high-dose-rate brachytherapy (HDR-BT) combined with external beam radiotherapy (EBRT).Materials and Methods: Between July 1999 and September 2007, 15, 51 and 41 patients considered as low-risk group (stage < or = T2a, PSA < or = 10 ng/mL, and Gleason score (GS) < or = 6), intermediate-risk group (stage = T2b, 10 < PSA < or = 20 ng/mL, or GS = 7), and high-risk group (stage > or = T2c, PSA >20 ng/mL, or Gleason score > or = 8), respectively, were treated with HDR-BT followed by EBRT at Kochi Medical School Hospital in Japan. Patient age ranged from 55 to 81 years (median 71). Forty-two patients had received neoadjuvant hormonal therapy, which was stopped at the beginning of radiotherapy in all cases. Patients were treated with EBRT to 39–45 Gy in 13–25 fractions, and HDR-BT to 18 Gy in 2–3 fractions for prostate. Adjuvant hormonal therapy was not performed until biochemical failure or clinical recurrence became apparent. PSA failure was defined as the Phoenix definition of nadir + 2ng/mL. The bRFS rates were estimated using the Kaplan-Meier method. The median followup was 60 months (range, 36 – 134 months). Cox proportional hazards regression analysis was used for univariate and multivariate analyses examining these factors in relation to bRFS: clinical T stage, initial PSA level, GS and use of neoadjuvant hormonal therapy. A two-side p value of <0.05 was considered statistically-significant.Results: The 5-year bRFS rate in low-, intermediate- and high-risk group were 100%, 97.9%, and 83.7%, respectively. The 5-year bRFS rate in high-risk group was statistically inferior to that in intermediate-risk group (p = 0.0206). On univariate and multivariate analyses, clinical T state remained an independent predictor of bRES. None of initial PSA level, GS, or use of neoadjuvant hormonal therapy was not predictive factor for bRFS of CaP patient with HDR-BT combined with EBRT.Conclusions: Clinical T3 CaP carried a worse bRFS than clinical T1-2 Cap. For the improvement of bRFS in T3Cap, adjuvant hormonal therapy may be needed for HDR-BT combined with EBRT. Purpose: The aim of this study is to determine what kind of clinical factors were predictive for biochemical relapse-free survival (bRFS) of prostate cancer (CaP) patients treated with high-dose-rate brachytherapy (HDR-BT) combined with external beam radiotherapy (EBRT). Materials and Methods: Between July 1999 and September 2007, 15, 51 and 41 patients considered as low-risk group (stage < or = T2a, PSA < or = 10 ng/mL, and Gleason score (GS) < or = 6), intermediate-risk group (stage = T2b, 10 < PSA < or = 20 ng/mL, or GS = 7), and high-risk group (stage > or = T2c, PSA >20 ng/mL, or Gleason score > or = 8), respectively, were treated with HDR-BT followed by EBRT at Kochi Medical School Hospital in Japan. Patient age ranged from 55 to 81 years (median 71). Forty-two patients had received neoadjuvant hormonal therapy, which was stopped at the beginning of radiotherapy in all cases. Patients were treated with EBRT to 39–45 Gy in 13–25 fractions, and HDR-BT to 18 Gy in 2–3 fractions for prostate. Adjuvant hormonal therapy was not performed until biochemical failure or clinical recurrence became apparent. PSA failure was defined as the Phoenix definition of nadir + 2ng/mL. The bRFS rates were estimated using the Kaplan-Meier method. The median followup was 60 months (range, 36 – 134 months). Cox proportional hazards regression analysis was used for univariate and multivariate analyses examining these factors in relation to bRFS: clinical T stage, initial PSA level, GS and use of neoadjuvant hormonal therapy. A two-side p value of <0.05 was considered statistically-significant. Results: The 5-year bRFS rate in low-, intermediate- and high-risk group were 100%, 97.9%, and 83.7%, respectively. The 5-year bRFS rate in high-risk group was statistically inferior to that in intermediate-risk group (p = 0.0206). On univariate and multivariate analyses, clinical T state remained an independent predictor of bRES. None of initial PSA level, GS, or use of neoadjuvant hormonal therapy was not predictive factor for bRFS of CaP patient with HDR-BT combined with EBRT. Conclusions: Clinical T3 CaP carried a worse bRFS than clinical T1-2 Cap. For the improvement of bRFS in T3Cap, adjuvant hormonal therapy may be needed for HDR-BT combined with EBRT.