Verma Vivek, Kulkarni Rajesh R, Bhirud Abhijeet R, Bennion Nathan R, McComb Rodney D, Lin Chi
Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, NE, USA.
Department of Pathology, University of Nebraska Medical Center, Omaha, NE, USA.
Rep Pract Oncol Radiother. 2016 Jan-Feb;21(1):84-9. doi: 10.1016/j.rpor.2015.10.002. Epub 2015 Nov 21.
A seven-year-old male underwent surgical resection and chemoradiation for average risk medulloblastoma; twelve years later, the presence of a necrotic and infiltrative mass in the same area and invading the brainstem prompted a subtotal resection. Pathology was indicative of glioblastoma. He was then treated with concurrent temozolomide and using biologically effective dose calculations for gross residual tumor tissue in the brainstem as well as brainstem tolerance, a radiotherapy dose of 3750 cGy was chosen, fractionated in twice-daily fractions of 125 cGy each. The gross tumor volume was expanded with a 5 mm margin to the planning target volume, which was also judiciously subtracted from the normal brainstem. He completed his radiotherapy course with subsequent imaging free of residual tumor and continued adjuvant temozolomide and remains under follow-up surveillance. This case underscores the rarity of metachronous medulloblastoma and glioblastoma, of which only five known cases heretofore have been described. We discuss the technicalities of radiotherapy planning in this patient, including common hurdles for radiation oncologists in similar patients.
一名七岁男性因平均风险髓母细胞瘤接受了手术切除及放化疗；十二年后，同一区域出现坏死性浸润性肿块并侵犯脑干，遂进行了次全切除。病理结果显示为胶质母细胞瘤。随后他接受了同步替莫唑胺治疗，并根据脑干大体残留肿瘤组织的生物等效剂量计算以及脑干耐受性，选择了3750厘戈瑞的放疗剂量，分两次每日给予，每次125厘戈瑞。大体肿瘤体积外扩5毫米作为计划靶体积，同时也谨慎地从正常脑干体积中减去。他完成了放疗疗程，后续影像检查未发现残留肿瘤，继续接受辅助替莫唑胺治疗，目前仍在随访监测中。该病例凸显了异时性髓母细胞瘤和胶质母细胞瘤的罕见性，此前仅描述过五例已知病例。我们讨论了该患者放疗计划的技术细节，包括放射肿瘤学家在类似患者中常见的障碍。
