Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
Int J Radiat Oncol Biol Phys. 2012 Feb 1;82(2):765-72. doi: 10.1016/j.ijrobp.2010.10.057. Epub 2011 Jan 13.
Semicontinuous low-dose-rate teletherapy (SLDR) is a novel irradiation strategy that exploits the increased radiosensitivity of glial cells in a narrow range of reduced dose rate. We present the final report of a prospective Phase I/II study testing the feasibility of SLDR for the treatment of recurrent gliomas.
Patients with previously irradiated recurrent gliomas were enrolled from November 1993 to March 1998. Patients received SLDR, delivered 6 to 8 hours/day at a dose rate of 40 to 50 cGy/hour for a total dose of 30 to 35 Gy given over 12 days using a modified cobalt-60 treatment unit. Acute central nervous system toxicity after SLDR treatment was the primary endpoint. Overall survival was a secondary endpoint.
Twenty patients were enrolled (14 World Health Organization Grade 4 glioma, 5 Grade 2 glioma, 1 ependymoma). No patients developed ≥ Grade 3 central nervous system toxicity at 3 months without radiographic evidence of tumor progression. Overall survival after SLDR was 56% at 6 months, 28% at 12 months, and 17% at 24 months. One patient survived >48 months, and 1 patient survived >60 months after SLDR treatment. Re-resection before SLDR treatment significantly improved 1-year overall survival for all patients and patients with Grade 4 glioma.
The delivery of SLDR is feasible in patients with recurrent gliomas and resulted in improved outcomes for patients who underwent re-resection. There were 2 long-term survivors (>48 months). This pilot study supports the notion that reduced dose rate influences the efficacy and tolerance of reirradiation in the treatment of recurrent gliomas.
半连续低剂量率远程治疗（SLDR）是一种新的辐射策略，利用胶质细胞在小剂量率范围内的增加的放射敏感性。我们报告了一项前瞻性 I/II 期研究的最终报告，该研究测试了 SLDR 治疗复发性神经胶质瘤的可行性。
从 1993 年 11 月至 1998 年 3 月，招募了先前接受过放射治疗的复发性神经胶质瘤患者。患者接受 SLDR 治疗，每天治疗 6-8 小时，剂量率为 40-50cGy/小时，总剂量为 30-35Gy，在 12 天内使用改良钴-60 治疗单元完成。SLDR 治疗后的急性中枢神经系统毒性是主要终点。总生存率是次要终点。
共纳入 20 例患者（14 例世界卫生组织 4 级神经胶质瘤，5 例 2 级神经胶质瘤，1 例室管膜瘤）。没有患者在没有肿瘤进展的影像学证据的情况下，在 3 个月时出现≥3 级中枢神经系统毒性。SLDR 后的总生存率为 6 个月时 56%，12 个月时 28%，24 个月时 17%。1 例患者存活时间超过 48 个月，1 例患者存活时间超过 60 个月。SLDR 治疗前的再次切除显著改善了所有患者和 4 级神经胶质瘤患者的 1 年总生存率。
在复发性神经胶质瘤患者中，SLDR 的输送是可行的，并且对于接受再次切除的患者，结果得到了改善。有 2 例长期存活者（>48 个月）。这项初步研究支持这样的观点，即降低剂量率会影响复发性神经胶质瘤治疗中再照射的疗效和耐受性。
