Fukunaga-Johnson N, Lee J H, Sandler H M, Robertson P, McNeil E, Goldwein J W
Department of Radiation Oncology, University of Michigan, Ann Arbor, USA.
Int J Radiat Oncol Biol Phys. 1998 Aug 1;42(1):143-6. doi: 10.1016/s0360-3016(98)00178-3.
Craniospinal radiation (CSRT) followed by a boost to the entire posterior fossa (PF) is standard postoperative therapy for patients with medulloblastoma. A large proportion of recurrences after treatment are local, with approximately 50-70% of recurrences occurring in the PF. It is unclear, however, whether these failures are occurring in the original tumor bed or outside the tumor bed, but still within the PF. With improved diagnostic imaging, better definition of tumor volumes, and the use of three-dimensional conformal therapy (3D CRT), we may be able to restrict the boost volume to the tumor bed plus a margin without compromising local control. This retrospective study analyzes the patterns of failure within the PF in a series of patients treated with radiation therapy (RT).
From July 1986 through February 1996, 114 patients >18 months and <18 years with medulloblastoma were treated at the University of Michigan and Children's Hospital of Philadelphia, with RT following surgical resection. Of 114, 27 (24%) were found to have a recurrence and form the basis for this study. RT consisted of CSRT followed by a boost to the entire posterior fossa. Some patients received adjuvant chemotherapy. Patient's preoperative magnetic resonance imaging (MRI) and/or computerized tomography (CT) studies were used to compare the original tumor volume with the specific region of local relapse. Failure was defined as MRI or CT evidence of recurrence or positive cerebrospinal fluid cytology. Relapse was scored as local, if it was within the original tumor bed, and regional if it was outside of the tumor bed but still within the PF.
The median age of the 27 patients who relapsed was 8.6 years. Three patients were <3 years old. Of 27, 21 had disease localized to the PF. Of 26, 22 patients received chemotherapy during their treatment regimen; 1 patient did not have information on systemic treatment. The median dose of RT to the craniospinal axis was 32.5 Gy and to the PF was 55.2 Gy. The median time to recurrence was 19.5 months. Local failure within the tumor bed as any component of first failure occurred in 52% (14 of 27) of all failures, but as the solitary site of first failure in only 2 of 27 failures. Of 14 patients who failed in the tumor bed, 11 also failed in the spine, 8 of 14 also failed within the PF but outside the tumor bed, and 7 of 14 failed in all three locations. Local failure within the PF but outside the tumor bed as any component of first failure occurred in 41% (11 of 27) of all failures, but as the solitary site of first failure in only 1 of 27 failures. Of 11 patients who failed in the PF but outside the tumor bed, 9 also failed in the spine, 8 also failed within the tumor bed, and 7 failed in the all three locations. Of the failures outside the tumor bed but still within the PF, 7 of 11 failed in the leptomeninges, 1 in the brainstem parenchyma, and 3 in the PF parenchyma. Of 7 who failed in the PF leptomeninges, 6 also failed within the spine. Failure within the spine as any component of first failure occurred in 70% (19 of 27) of all failures and as the only site of first failure in 5 of 27 patients. Of 19 patients who failed in the spine, 11 also failed in the tumor bed, 9 also failed within the PF but outside the tumor bed, and 9 failed in the all three locations.
Leptomeningeal failure is a common component of failure and occurs in the leptomeninges of the PF, as well as the spine. Isolated tumor bed failure is a rarely observed event and occurred in only 2 of 27 failures described here. Similarly, parenchymal (nonleptomeningeal) failures in the PF but outside of the tumor bed were rare: 4 patients recurred in this manner, only 1 of whom was an isolated event without other sites of recurrence. Our data suggest that, when the entire PF is treated, very few failures develop in isolation in the PF outside the tumor bed. Further studies will be necessary to determine if RT to the tu
对于髓母细胞瘤患者，标准的术后治疗是颅脊髓放疗（CSRT），随后对整个后颅窝（PF）进行强化放疗。治疗后很大一部分复发是局部性的，约50 - 70%的复发发生在后颅窝。然而，尚不清楚这些复发是发生在原肿瘤床还是肿瘤床以外但仍在后颅窝内。随着诊断性影像学的改进、肿瘤体积定义的改善以及三维适形放疗（3D CRT）的应用，我们或许能够将强化放疗体积限制在肿瘤床加边缘区域，而不影响局部控制。这项回顾性研究分析了一系列接受放射治疗（RT）患者后颅窝内的失败模式。
从1986年7月至1996年2月，密歇根大学和费城儿童医院对114例年龄大于18个月且小于18岁的髓母细胞瘤患者进行了手术切除后放疗。在这114例患者中，27例（24%）出现复发，构成了本研究的基础。放疗包括颅脊髓放疗，随后对整个后颅窝进行强化放疗。部分患者接受了辅助化疗。利用患者术前的磁共振成像（MRI）和/或计算机断层扫描（CT）研究，将原肿瘤体积与局部复发的特定区域进行比较。失败定义为MRI或CT显示复发或脑脊液细胞学阳性。如果复发发生在原肿瘤床内，则记为局部复发；如果发生在肿瘤床以外但仍在后颅窝内，则记为区域复发。
27例复发患者的中位年龄为8.6岁。3例患者年龄小于3岁。27例患者中，21例疾病局限于后颅窝。26例患者中，22例在治疗过程中接受了化疗；1例患者没有全身治疗的信息。颅脊髓轴的中位放疗剂量为32.5 Gy，后颅窝的中位放疗剂量为55.2 Gy。复发的中位时间为19.5个月。作为首次失败的任何组成部分，肿瘤床内的局部失败在所有失败中占52%（27例中的14例），但作为首次失败的唯一部位仅在27例失败中的2例出现。在14例肿瘤床失败的患者中，11例脊柱也失败，14例中的8例在后颅窝内但肿瘤床外也失败，14例中的7例在所有三个部位都失败。作为首次失败的任何组成部分，后颅窝内但肿瘤床外的局部失败在所有失败中占41%（27例中的11例），但作为首次失败的唯一部位仅在27例失败中的1例出现。在11例在后颅窝内但肿瘤床外失败的患者中，9例脊柱也失败，8例肿瘤床内也失败，7例在所有三个部位都失败。在肿瘤床以外但仍在后颅窝内的失败中，11例中的7例在软脑膜复发，1例在脑干实质复发，3例在后颅窝实质复发。在7例在后颅窝软脑膜复发的患者中，6例脊柱也复发。作为首次失败的任何组成部分，脊柱失败在所有失败中占70%（27例中的19例），作为首次失败的唯一部位在27例患者中的5例出现。在19例脊柱失败的患者中，11例肿瘤床也失败，9例在后颅窝内但肿瘤床外也失败，9例在所有三个部位都失败。
软脑膜失败是常见的失败组成部分，发生在后颅窝的软脑膜以及脊柱。孤立的肿瘤床失败是罕见事件，在此描述的27例失败中仅2例出现。同样，后颅窝内但肿瘤床外的实质（非软脑膜）失败也很罕见：4例患者以这种方式复发，其中只有1例是没有其他复发部位的孤立事件。我们的数据表明，当对整个后颅窝进行治疗时，在后颅窝内肿瘤床以外很少有孤立的失败发生。需要进一步研究以确定对肿瘤……进行放疗是否……
