Nijjar T S, Simpson W J, Gadalla T, McCartney M
Department of Radiation, Oncology, Cross Cancer Institute, Edmonton, Alberta, Canada.
Cancer. 1993 Jun 15;71(12):4002-6. doi: 10.1002/1097-0142(19930615)71:12<4002::aid-cncr2820711234>3.0.co;2-w.
Oligodendrogliomas are rare central nervous system (CNS) tumors. Although surgery remains the primary treatment, the role of postoperative radiation treatment remains a matter of controversy. This study assesses whether postoperative radiation improves survival and local tumor control when compared with surgical treatment alone.
The medical records of 72 patients with the diagnosis of oligodendroglioma, registered at the Princess Margaret Hospital (PMH) between 1958 and 1984, were reviewed retrospectively. The data of 68 patients were evaluated, but 4 patients were excluded from the analysis because of inadequate follow-up. The median follow-up period at the time of analysis was 7.5 years. Tumors were classified as oligodendrogliomas, malignant oligodendrogliomas, or mixed oligoastrocytomas. Fifty-eight (85%) patients received postoperative irradiation at initial diagnosis, and 10 (15%) patients were treated with surgery alone. In most patients (76%), the radiation dose was 5000 cGy in 25 fractions given during a period of 5 weeks.
Five- and 10-year overall survival was 66% and 30%, respectively. Forty-two (62.0%) patients experienced disease relapse during the follow-up period. The median time to relapse from initial diagnosis was 2.6 years. Most tumor recurrences were at the primary site. Two patients developed distant metastasis within the CNS axis. Histologic subtype was the only significant prognostic factor for survival. The patients with oligodendroglioma and malignant oligodendroglioma had 5-year survival rates of 73% and 32%, respectively (P = 0.033).
The authors drew three conclusions. (1) Most patients eventually died with this tumor from local recurrence without distant metastasis. Local tumor control remains the major problem. (2) Tumor histologic subtype is a significant prognostic factor. (3) No statistically significant benefit can be attributed to postoperative irradiation; however, the number of patients not receiving radiation therapy was small (10). Thus, the role of radiation therapy remains a matter of controversy.
少突胶质细胞瘤是罕见的中枢神经系统（CNS）肿瘤。虽然手术仍然是主要治疗方法，但术后放疗的作用仍存在争议。本研究评估与单纯手术治疗相比，术后放疗是否能提高生存率和局部肿瘤控制率。
回顾性分析1958年至1984年间在玛格丽特公主医院（PMH）登记的72例诊断为少突胶质细胞瘤患者的病历。评估了68例患者的数据，但4例患者因随访不充分被排除在分析之外。分析时的中位随访期为7.5年。肿瘤分为少突胶质细胞瘤、恶性少突胶质细胞瘤或混合性少突星形细胞瘤。58例（85%）患者在初次诊断时接受了术后放疗，10例（15%）患者仅接受手术治疗。大多数患者（76%）的放疗剂量为5000厘戈瑞，分25次在5周内给予。
5年和10年总生存率分别为66%和30%。42例（62.0%）患者在随访期间出现疾病复发。从初次诊断到复发的中位时间为2.6年。大多数肿瘤复发发生在原发部位。2例患者在CNS轴内发生远处转移。组织学亚型是生存的唯一显著预后因素。少突胶质细胞瘤和恶性少突胶质细胞瘤患者的5年生存率分别为73%和32%（P = 0.033）。
作者得出三个结论。（1）大多数患者最终死于该肿瘤的局部复发，无远处转移。局部肿瘤控制仍然是主要问题。（2）肿瘤组织学亚型是一个显著的预后因素。（3）术后放疗没有统计学上的显著益处；然而，未接受放疗的患者数量较少（10例）。因此，放疗的作用仍存在争议。
