paediatrics Brussels 17

J Neurooncol (2006)

operative bed or if a tumor was visible on follow-up imaging studies.

ependymomas, although a few have also included pa- tients with MPEs [14–18]. According to these reports, the mainstay of spinal ependymoma treatment is sur- gery to obtain a histologic diagnosis and resect as much of the tumor as possible. Postoperative radiotherapy (RT) has also been advocated as an additional mean of controlling spinal ependymomas in patients who un- dergo subtotal resection (STR) [14–18]. However, the respective roles of surgery and adjuvant RT in the treatment of spinal ependymomas require further study. For ependymomas, some investigators have advocated minimal surgery and adjuvant RT, whereas others have reported good clinical outcomes with gross total resection (GTR) alone [19–23]. These viewpoints are not necessarily relevant to the management of MPE, however, which represents a more favorable, histopathologic variant of ependymoma with a distinct clinical course. In this paper, we report the outcomes from a single institutional experience with 35 spinal MPEs treated with either surgery alone or surgery and adjuvant RT. This study involved 35 patients with histologically verified spinal MPE treated at The University of Texas M.D. Anderson Cancer Center between 1968 and 2002. The institutional review board at M.D. Anderson Cancer Center approved the study design, which in- volved a retrospective review of the patients’ medical records and a waiver of informed consent. The infor- mation necessary for the study was obtained through this review. The current vital status of all 35 patients was obtained from the M.D. Anderson Cancer Center tumor registry, the United States Social Security database, mailed questionnaires, and telephone inter- views. Follow-up data of varying duration were avail- able for all patients in this study. The extent of surgery was determined from the surgical reports and/or postoperative imaging studies. The surgery was classified as a GTR if the surgeon had described a complete removal of the tumor or if there was no evidence of tumor on scans from postoperative computed tomography (CT) or magnetic resonance imaging (MRI). The surgery was classified as a STR if the surgeon had observed unresected tumor in the Surgical treatment Patients and methods Study group

Radiation treatment

All patients were treated with either linear accelerators that used 6 MV or 18 MV energies or a 60 Co machine (for patients treated during the earlier part of the study). The most common technique used was a single posterior–anterior field (in 86% of the patients); although 14% of the patients received RT with 3-dimensional treatment planning. The RT treatment volume was the primary tumor plus a 3–5 cm margin based on the imaging results and the treating physi- cian’s preferences. The cone-down field encompassed the primary tumor with a 2 cm margin.

Chemotherapy

No patient in this study received initial or adjuvant chemotherapy. Four patients received salvage chemotherapy due to recurrence of leptomeningeal disease.

Functional evaluation

Neurologic function was evaluated by use of a Frankel classification system (A = Complete motor and sen- sory loss, B = Preserved sensation only, C = Motor and sensory incomplete function, D = Useful motor function, E = No motor or sensory function disorder) [24]. Grades were assigned before adjuvant RT and last follow-up visits. Data analysis was performed by using Stata 9.0 statis- tical software (Stata, College Station, TX). The Pear- son’s v 2 test was used to assess measures of association in frequency tables. The survival function was deter- mined by using Kaplan–Meier estimates. The log-rank test was used to assess the equality of the survival function across groups. The equality of means for continuous variables was assessed by using the t -test. Statistical tests were based on a two-sided significance level, and a P value of 0.05 or less was considered to be statistically significant. The survival time was calculated from the diagnosis date to the first occurrence of the considered event (i.e., local spine recurrence alone, distant spinal failure alone, or any recurrence). More specifically, overall survival (OS) was the time from diagnosis to death Statistical analysis

123