Department of Radiation Oncology, University of Michigan Health System, Ann Arbor, MI 48109, USA.
Cancer. 2013 Feb 1;119(3):681-90. doi: 10.1002/cncr.27784. Epub 2012 Aug 14.
The objective of this study was to determine whether the addition of low-dose-rate brachytherapy or androgen-deprivation therapy (ADT) improves clinical outcome in patients with high-risk prostate cancer (HiRPCa) who received dose-escalated radiotherapy (RT).
Between 1995 and 2010, 958 patients with HiRPCa were treated at Schiffler Cancer Center (n = 484) or at the University of Michigan (n = 474) by receiving either dose-escalated external-beam RT (EBRT) (n = 510; minimum prescription dose, 75 grays [Gy]; median dose, 78 Gy) or combined-modality RT (CMRT) consisting of (103) Pd implants (n = 369) or (125) I implants (n = 79) both with pelvic irradiation (median prescription dose, 45 Gy). The cumulative incidences of biochemical failure (BF) and prostate cancer-specific mortality (PCSM) were estimated by using the Kaplan-Meier method and Fine and Gray regression analysis.
The median follow-up was 63.2 months (interquartile range, 35.4-99.0 months), and 250 patients were followed for >8 years. Compared with CMRT, patients who received EBRT had higher prostate-specific antigen levels, higher tumor classification, lower Gleason sum, and more frequent receipt of ADT for a longer duration. The 8-year incidence BF and PCSM among patients who received EBRT was 40% (standard error, 38%-44%) and 13% (standard error, 11%-15%) compared with 14% (standard error, 12%-16%; P < .0001) and 7% (standard error 6%-9%; P = .003) among patients who received CMRT. On multivariate analysis, the hazard ratios (HRs) for BF and PCSM were 0.35 (95% confidence interval [CI], 0.23-0.52; P < .0001) and 0.41 (95% CI, 0.23-0.75; P < .003), favoring CMRT. Increasing duration of ADT predicted decreased BF (P = .04) and PCSM (P = .001), which was greatest with long-term ADT (BF: HR, 0.33; P < .0001; 95% CI, 0.21-0.52; PCSM: HR, 0.30; P = .001; 95% CI, 0.15-0.6) even in the subgroup that received CMRT.
In this retrospective comparison, both low-dose-rate brachytherapy boost and ADT were associated with decreased risks of BF and PCSM compared with EBRT.
本研究旨在确定在接受高剂量率近距离放射治疗（brachytherapy）或雄激素剥夺治疗（androgen-deprivation therapy，ADT）的高危前列腺癌（high-risk prostate cancer，HiRPCa）患者中，加用低剂量率近距离放射治疗或 ADT 是否能改善接受剂量递增放疗（dose-escalated radiotherapy，RT）的患者的临床结局。
1995 年至 2010 年间，958 例 HiRPCa 患者在 Schiffler 癌症中心（n = 484）或密歇根大学（n = 474）接受治疗，分别接受剂量递增外照射 RT（EBRT）（n = 510；最小处方剂量 75 戈瑞[grays，Gy]；中位剂量 78 Gy）或包括盆腔照射的联合治疗（combined-modality RT，CMRT）[103Pd 植入（n = 369）或 125I 植入（n = 79）]。采用 Kaplan-Meier 法和 Fine 和 Gray 回归分析估计生化失败（biochemical failure，BF）和前列腺癌特异性死亡率（prostate cancer-specific mortality，PCSM）的累积发生率。
中位随访时间为 63.2 个月（四分位间距，35.4-99.0 个月），250 例患者随访时间超过 8 年。与 CMRT 相比，接受 EBRT 的患者前列腺特异性抗原水平更高、肿瘤分级更高、Gleason 评分更低、接受 ADT 的比例更高且持续时间更长。EBRT 组的 8 年 BF 和 PCSM 发生率为 40%（标准误差，38%-44%）和 13%（标准误差，11%-15%），而 CMRT 组分别为 14%（标准误差，12%-16%；P <.0001）和 7%（标准误差，6%-9%；P =.003）。多变量分析显示，BF 和 PCSM 的风险比（hazard ratio，HR）分别为 0.35（95%置信区间，0.23-0.52；P <.0001）和 0.41（95%置信区间，0.23-0.75；P <.003），CMRT 更具优势。ADT 持续时间的增加预测 BF（P =.04）和 PCSM（P =.001）的降低，长期 ADT 的效果最大（BF：HR，0.33；P <.0001；95%CI，0.21-0.52；PCSM：HR，0.30；P =.001；95%CI，0.15-0.6），即使在接受 CMRT 的亚组中也是如此。
在这项回顾性比较研究中，与 EBRT 相比，低剂量率近距离放射治疗加 ADT 均与 BF 和 PCSM 风险降低相关。
