Department of Radiation Medicine, Georgetown University Hospital, Washington, DC, USA.
Technol Cancer Res Treat. 2010 Oct;9(5):453-62. doi: 10.1177/153303461000900503.
Clinical data suggest that large radiation fractions are biologically superior to smaller fraction sizes in prostate cancer radiotherapy. The CyberKnife is an appealing delivery system for hypofractionated radiosurgery due to its ability to deliver highly conformal radiation and to track and adjust for prostate motion in real-time. We report our early experience using the CyberKnife to deliver a hypofractionated stereotactic body radiation therapy (SBRT) boost to patients with intermediate- to high-risk prostate cancer. Twenty-four patients were treated with hypofractionated SBRT and supplemental external radiation therapy plus or minus androgen deprivation therapy (ADT). Patients were treated with SBRT to a dose of 19.5 Gy in 3 fractions followed by intensity modulated radiation therapy (IMRT) to a dose of 50.4 Gy in 28 fractions. Quality of life data were collected with American Urological Association (AUA) symptom score and Expanded Prostate Cancer Index Composite (EPIC) questionnaires before and after treatment. PSA responses were monitored; acute urinary and rectal toxicities were assessed using Common Toxicity Criteria (CTC) v3. All 24 patients completed the planned treatment with an average follow-up of 9.3 months. For patients who did not receive ADT, the median pre-treatment PSA was 10.6 ng/ml and decreased in all patients to a median of 1.5 ng/ml by 6 months post-treatment. Acute effects associated with treatment included Grade 2 urinary and gastrointestinal toxicity but no patient experienced acute Grade 3 or greater toxicity. AUA and EPIC scores returned to baseline by six months post-treatment. Hypofractionated SBRT combined with IMRT offers radiobiological benefits of a large fraction boost for dose escalation and is a well tolerated treatment option for men with intermediate- to high-risk prostate cancer. Early results are encouraging with biochemical response and acceptable toxicity. These data provide a basis for the design of a phase II clinical trial.
临床资料表明，前列腺癌放射治疗中，大分割剂量比小分割剂量更具生物学优势。由于 CyberKnife 能够提供高度适形的辐射，并实时跟踪和调整前列腺运动，因此它是一种很有吸引力的分次立体定向放射外科治疗（Hypofractionated radiosurgery）的传递系统。我们报告了使用 CyberKnife 为中高危前列腺癌患者提供分次立体定向体部放射治疗（Hypofractionated stereotactic body radiation therapy，SBRT）推量的早期经验。24 例患者接受了 Hypofractionated SBRT 治疗，并联合或不联合雄激素剥夺治疗（Androgen deprivation therapy，ADT）的外部放射治疗。患者接受 SBRT 治疗，剂量为 19.5 Gy，分 3 次；然后接受调强放射治疗（Intensity modulated radiation therapy，IMRT），剂量为 50.4 Gy，分 28 次。在治疗前后，通过美国泌尿外科学会（American Urological Association，AUA）症状评分和前列腺癌指数综合评分（Expanded Prostate Cancer Index Composite，EPIC）问卷收集生活质量数据。监测 PSA 反应；使用通用毒性标准（Common Toxicity Criteria，CTC）v3 评估急性尿和直肠毒性。所有 24 例患者均完成了计划治疗，平均随访 9.3 个月。对于未接受 ADT 的患者，中位治疗前 PSA 为 10.6 ng/ml，所有患者在治疗后 6 个月时降至中位 1.5 ng/ml。治疗相关的急性影响包括 2 级尿和胃肠道毒性，但没有患者发生急性 3 级或更高级别的毒性。AUA 和 EPIC 评分在治疗后 6 个月时恢复到基线。Hypofractionated SBRT 联合 IMRT 提供了大分割剂量推量的放射生物学优势，可进行剂量升级，是中高危前列腺癌患者的一种耐受良好的治疗选择。生化反应和可接受的毒性令人鼓舞，早期结果令人振奋。这些数据为设计 II 期临床试验提供了依据。
