Department of Radiation Oncology, Inha University Hospital, Inha University of Medicine, Inchon, South Korea.
Prostate Int. 2016 Mar;4(1):25-9. doi: 10.1016/j.prnil.2015.12.001. Epub 2015 Dec 12.
Stereotactic body radiotherapy (SBRT) has emerged as an effective treatment for localized prostate cancer. The purpose of this study was to compare the prostate-specific antigen (PSA) kinetics between conventionally fractionated external beam radiotherapy (CF-EBRT) and SBRT boost after whole pelvis EBRT (WP-EBRT) in localized prostate cancer.
A total of 77 patients with localized prostate cancer [T-stage, T1-T3; Gleason score (GS) 5-9; PSA < 20 ng/mL] were enrolled. A total of 35 patients were treated with SBRT boost (21 Gy in 3 fractions) after WP-EBRT and 42 patients were treated with CF-EBRT (45 Gy WP-EBRT and boost of 25.2-30.6 Gy in 1.8-Gy fractions). PSA nadir and rate of change in PSA (slope) were calculated and compared.
With a median follow-up of 52.4 months (range, 14-74 months), the median PSA nadir and slope for SBRT boost were 0.29 ng/mL and -0.506, -0.235, -0.129, and -0.092 ng/mL/mo, respectively, for durations of 1 year, 2 years, 3 years, and 4 years postradiotherapy. Similarly, for CF-EBRT, the median PSA nadir and slopes were 0.39 ng/mL and -0.720 ng/mL/mo, -0.204 ng/mL/mo, -0.121 ng/mL/mo, and -0.067 ng/mL/mo, respectively. The slope of CF-EBRT was significantly different with a greater median rate of change for 1 year postradiotherapy than that of SBRT boost (P = 0.018). Contrastively, the slopes of SBRT boost for durations of 2 years, 3 years, and 4 years tended to be continuously greater than that of CF-EBRT. The significantly lower PSA nadir was observed in SBRT boost (median nadir 0.29 ng/mL) compared with CF-EBRT (median nadir 0.35 ng/mL, P = 0.025). Five-year biochemical failure (BCF) free survival was 94.3% for SBRT boost and 78.6% for CF-EBRT (P = 0.012).
Patients treated with SBRT boost after WP-EBRT experienced a lower PSA nadir and there tended to be a continuously greater rate of decline of PSA for durations of 2 years, 3 years, and 4 years than with CF-EBRT. The improved PSA kinetics of SBRT boost over CF-EBRT led to favorable BCF free survival.
立体定向体部放射治疗（SBRT）已成为治疗局限性前列腺癌的有效方法。本研究旨在比较全骨盆外照射放疗（WP-EBRT）后常规分割外照射放疗（CF-EBRT）与 SBRT 推量治疗局限性前列腺癌患者的前列腺特异性抗原（PSA）动力学。
共纳入 77 例局限性前列腺癌患者[T 分期，T1-T3；Gleason 评分（GS）5-9；PSA<20ng/mL]。35 例患者接受 WP-EBRT 后 SBRT 推量治疗（21Gy，3 次），42 例患者接受 CF-EBRT（45Gy WP-EBRT 和 1.8Gy 分次的 25.2-30.6Gy 推量）。计算并比较 PSA 最低值和 PSA 变化率（斜率）。
中位随访 52.4 个月（范围 14-74 个月），SBRT 推量的 PSA 最低值和斜率分别为 0.29ng/mL 和-0.506、-0.235、-0.129 和-0.092ng/mL/月，分别在放疗后 1、2、3 和 4 年。同样，CF-EBRT 的 PSA 最低值和斜率分别为 0.39ng/mL 和-0.720ng/mL/月、-0.204ng/mL/月、-0.121ng/mL/月和-0.067ng/mL/月。CF-EBRT 的斜率差异有统计学意义，1 年时 PSA 变化率的中位数更高（P=0.018）。相比之下，SBRT 推量在 2、3 和 4 年时的斜率呈持续增加趋势，大于 CF-EBRT。SBRT 推量的 PSA 最低值明显低于 CF-EBRT（中位值 0.29ng/mL 比 0.35ng/mL，P=0.025）。SBRT 推量的 5 年生化无失败（BCF）生存率为 94.3%，CF-EBRT 为 78.6%（P=0.012）。
WP-EBRT 后接受 SBRT 推量治疗的患者 PSA 最低值较低，2、3 和 4 年时 PSA 下降率呈持续增加趋势，大于 CF-EBRT。SBRT 推量较 CF-EBRT 改善 PSA 动力学，导致 BCF 无失败生存率较好。
