Department of Radiation Oncology/CyberKnife Center, Soonchunhyang University Seoul Hospital, Daesagwan-ro 59, Youngsan-gu, Seoul, 04401, Republic of Korea.
Department of Radiation Oncology, Hanyang University College of Medicine, Seoul, Republic of Korea.
Radiat Oncol. 2018 Nov 23;13(1):230. doi: 10.1186/s13014-018-1182-z.
To evaluate the treatment outcome and prostate-specific antigen (PSA) change after stereotactic body radiotherapy (SBRT) for localized prostate cancer.
Patients with localized prostate cancer treated with SBRT at three academic hospitals were enrolled. Treatment was delivered using Cyberknife with dose range from 35 to 37.5 Gy in 5 fractions. Biochemical failure (BCF) was assessed with Phoenix definition and toxicities were scored with Radiation Therapy Oncology Group (RTOG) toxicity criteria. The PSA kinetics were analyzed in patients who received no androgen deprivation therapy (ADT) and showed no recurrence.
Of the total 88 patients, 14 patients (15.9%) received ADT. After median follow-up of 63.8 months, the 5-year BCF free survival (BCFFS) was 94.7%. Two patients experienced late grade ≥ 3 GI toxicities (2.2%). The median nadir PSA was 0.12 ng/mL (range, 0.00-2.62 ng/mL) and the median time to nadir was 44.8 months (range, 0.40-85.7 months). Patients who reached nadir before 24 months showed poorer BCFFS than the others. The rate of PSA decline was maximum in the first year after treatment and gradually decreased with time. The pattern of PSA change was significantly different according to the risk groups (p = 0.011) with the slope of - 0.139, - 0.161 and - 0.253 ng/mL/month in low-, intermediate- and high-risk groups, respectively.
SBRT for localized prostate cancer showed favorable efficacy with minimal toxicities. The time to PSA nadir was significantly associated with treatment outcome. PSA revealed rapid initial decline and slower decrease with longer follow-up and the patterns of PSA changes were different according to the risk groups.
评估立体定向体部放疗（SBRT）治疗局限性前列腺癌的治疗效果和前列腺特异性抗原（PSA）变化。
在三所学术医院接受 SBRT 治疗的局限性前列腺癌患者被纳入本研究。采用 Cyberknife 治疗，剂量范围为 35 至 37.5Gy，分为 5 个剂量。采用 Phoenix 定义评估生化失败（BCF），采用放射治疗肿瘤学组（RTOG）毒性标准评分毒性。对未接受雄激素剥夺治疗（ADT）且无复发的患者进行 PSA 动力学分析。
在 88 例患者中，有 14 例（15.9%）接受了 ADT。中位随访 63.8 个月后，5 年无 BCF 生存率（BCFFS）为 94.7%。有 2 例患者发生晚期≥3 级胃肠道毒性（2.2%）。中位 PSA 最低值为 0.12ng/mL（范围，0.00-2.62ng/mL），PSA 最低值时间为 44.8 个月（范围，0.40-85.7 个月）。在 24 个月前达到 PSA 最低值的患者，其 BCFFS 较其他患者差。PSA 下降速度在治疗后第一年最大，随着时间的推移逐渐降低。根据风险组，PSA 变化模式显著不同（p=0.011），低、中、高危组 PSA 斜率分别为-0.139、-0.161 和-0.253ng/mL/月。
SBRT 治疗局限性前列腺癌疗效良好，毒性最小。PSA 最低值时间与治疗效果显著相关。PSA 初始迅速下降，随随访时间延长逐渐下降，PSA 变化模式根据风险组而不同。
