Departments of Radiation Oncology, University of California Los Angeles School of Medicine, Los Angeles, CA 90095, USA.
Int J Radiat Oncol Biol Phys. 2012 Feb 1;82(2):877-82. doi: 10.1016/j.ijrobp.2010.11.054. Epub 2011 Feb 6.
Hypofractionated radiotherapy has an intrinsically different normal tissue and tumor radiobiology. The results of a prospective trial of stereotactic body radiotherapy (SBRT) for prostate cancer with long-term patient-reported toxicity and tumor control rates are presented.
From 2003 through 2009, 67 patients with clinically localized low-risk prostate cancer were enrolled. Treatment consisted of 36.25 Gy in 5 fractions using SBRT with the CyberKnife as the delivery technology. No patient received hormone therapy. Patient self-reported bladder and rectal toxicities were graded on the Radiation Therapy Oncology Group scale (RTOG).
Median follow-up was 2.7 years. There were no grade 4 toxicities. Radiation Therapy Oncology Group Grade 3, 2, and 1 bladder toxicities were seen in 3% (2 patients), 5% (3 patients), and 23% (13 patients) respectively. Dysuria exacerbated by urologic instrumentation accounted for both patients with Grade 3 toxicity. Urinary incontinence, complete obstruction, or persistent hematuria was not observed. Rectal Grade 3, 2, and 1 toxicities were seen in 0, 2% (1 patient), and 12.5% (7 patients), respectively. Persistent rectal bleeding was not observed. Low-grade toxicities were substantially less frequent with QOD vs. QD dose regimen (p = 0.001 for gastrointestinal and p = 0.007 for genitourinary). There were two prostate-specific antigen (PSA), biopsy-proven failures with negative metastatic workup. Median PSA at follow-up was 0.5 ± 0.72 ng/mL. The 4-year Kaplan-Meier PSA relapse-free survival was 94% (95% confidence interval, 85%-102%).
Significant late bladder and rectal toxicities from SBRT for prostate cancer are infrequent. PSA relapse-free survival compares favorably with other definitive treatments. The current evidence supports consideration of stereotactic body radiotherapy among the therapeutic options for localized prostate cancer.
调强放疗具有内在不同的正常组织和肿瘤放射生物学。本文呈现了一项立体定向体部放疗（SBRT）治疗前列腺癌的前瞻性研究结果，包括长期的患者报告毒性和肿瘤控制率。
2003 年至 2009 年期间，共纳入 67 例临床局限性低危前列腺癌患者。治疗采用 SBRT，使用 CyberKnife 作为递送技术，给予 36.25Gy，共 5 次。所有患者均未接受激素治疗。患者自我报告的膀胱和直肠毒性按照放射治疗肿瘤学组（RTOG）标准进行分级。
中位随访时间为 2.7 年。无 4 级毒性。3%（2 例）、5%（3 例）和 23%（13 例）的患者分别出现 RTOG 3 级、2 级和 1 级膀胱毒性。因泌尿科器械使用而加重的排尿困难导致了 2 例 3 级毒性。未观察到尿失禁、完全梗阻或持续血尿。0 级、2%（1 例）和 12.5%（7 例）的患者分别出现直肠 3 级、2 级和 1 级毒性。未观察到持续直肠出血。QOD 剂量方案的胃肠道和泌尿生殖系统低级别毒性明显少于 QD 剂量方案（p=0.001 和 p=0.007）。2 例前列腺特异性抗原（PSA）活检证实生化复发，经全身检查无转移。随访时中位 PSA 为 0.5±0.72ng/mL。4 年的 Kaplan-Meier PSA 无复发生存率为 94%（95%置信区间，85%-102%）。
SBRT 治疗前列腺癌的迟发性膀胱和直肠毒性少见。PSA 无复发生存率与其他确定性治疗相当。目前的证据支持将立体定向体部放疗作为局限性前列腺癌的治疗选择之一。
