Chojnacka M, Pędziwiatr K, Skowrońska-Gardas A, Perek-Polnik M, Perek D, Olasek P
1 Department of Radiotherapy, M. Skłodowska-Curie Memorial Cancer Center-Institute, Warsaw, Wawelska, Poland.
Br J Radiol. 2014 Sep;87(1041):20140211. doi: 10.1259/bjr.20140211. Epub 2014 Jun 27.
The second tumour (ST) occurrence is a relatively uncommon late complication of radiotherapy but represents one of the most significant issues, especially in childhood oncology. We describe our experience with patients who developed second brain neoplasm following cranial irradiation in childhood.
We identified nine patients who received radiotherapy owing to central nervous system tumour in childhood and subsequently developed the second brain tumour. The full clinical and radiological documentation and histopathological reports were reviewed. Risk factors such as age at irradiation, latency period to ST diagnosis, radiotherapy doses and volumes and other therapy methods were evaluated. We correlated the ST location with the three levels of irradiation dose (high, >40 Gy; medium, 25-40 Gy; and low <25 Gy).
Five meningiomas and four gliomas occurred as the ST after the mean time of 11.7 years after radiotherapy. The average age of children during irradiation was 4.6 years. The shorter latency time to the ST induction was found in children treated with chemotherapy (9 years vs 17.2 years). Seven STs developed in the area of high and moderate dose (>25 Gy), only two low-grade gliomas appeared in the low-dose region.
Our data suggest that the STs usually develop in the brain tissues that received doses >25 Gy in patients irradiated at a young age.
The low-dose volume seems not to be so significant for second brain neoplasm induction. Therefore, the modern intensity-modulated radiotherapy technique could be safely applied in paediatric patients.
第二原发肿瘤（ST）的发生是放疗相对少见的晚期并发症，但却是最重要的问题之一，尤其是在儿童肿瘤学领域。我们描述了儿童期接受头颅放疗后发生第二脑肿瘤患者的情况。
我们确定了9例儿童期因中枢神经系统肿瘤接受放疗并随后发生第二脑肿瘤的患者。回顾了完整的临床、放射学资料以及组织病理学报告。评估了诸如放疗时的年龄、ST诊断的潜伏期、放疗剂量和范围以及其他治疗方法等危险因素。我们将ST的位置与三个放疗剂量水平（高剂量，>40 Gy；中剂量，25 - 40 Gy；低剂量，<25 Gy）进行了关联。
放疗后平均11.7年出现了5例脑膜瘤和4例胶质瘤作为ST。放疗时儿童的平均年龄为4.6岁。接受化疗的儿童ST诱导的潜伏期较短（9年对17.2年）。7例ST发生在高剂量和中剂量区域（>25 Gy），仅2例低级别胶质瘤出现在低剂量区域。
我们的数据表明，在年幼时接受放疗的患者中，ST通常发生在接受剂量>25 Gy的脑组织中。
低剂量区域对第二脑肿瘤的诱导似乎不那么重要。因此，现代调强放疗技术可安全应用于儿科患者。
