Cauda equina ependymomas: surgical treatment and long-term outcomes in a series of 125 patients

Abstract

OBJECTIVE Cauda equina ependymoma (CEE) is a rare tumor for which little information is available on the oncological and clinical outcomes of patients. In this study the authors aimed to address functional, oncological, and quality-of-life (QOL) outcomes in a large series of consecutive patients operated on at their institution during the past 20 years. METHODS The records of 125 patients who underwent surgery between January 1998 and September 2018 were reviewed. Analyzed variables included demographic, clinical, radiological, surgical, and histopathological features. Neurological outcomes were graded according to the McCormick and Kesselring scales. The QOL at follow-up was evaluated by administering the EQ-5DL questionnaire. RESULTS On admission, 84% of patients had a McCormick grade of I and 76.8% had a Kesselring score of 0. At follow-up (clinical 8.13 years; radiological 5.87 years) most scores were unchanged. Sacral level involvement (p = 0.029) and tumor size (p = 0.002) were predictors of poor functional outcome at discharge. Tumor size (p = 0.019) and repeated surgery (p < 0.001) were predictors of poor outcome. A preoperative McCormick grade ≥ III and Kesselring grade ≥ 2 were associated with worse outcomes (p = 0.035 and p = 0.002, respectively). Myxopapillary ependymoma (MPE) was more frequent than grade II ependymoma (EII). The overall rate of gross-total resection (GTR) was 91.2% and rates were significantly higher for patients with EII (98%) than for those with MPE (84%) (p = 0.0074). On multivariate analysis, the only factor associated with GTR was the presence of a capsule (p = 0.011). Seventeen patients (13.7%) had recurrences (13 MPE, 4 EII; 76.4% vs 23.6%; p = 0.032). The extent of resection was the only factor associated with recurrence (p = 0.0023) and number of surgeries (p = 0.006). Differences in progression-free survival (PFS) were seen depending on the extent of resection at first operation (p < 0.001), subarachnoid seeding (p = 0.041), piecemeal resection (p = 0.004), and number of spine levels involved (3 [p = 0.016], 4 [p = 0.011], or ≥ 5 [p = 0.013]). At follow-up a higher proportion of EII than MPE patients were disease free (94.7% vs 77.7%; p = 0.007). The QOL results were inferior in almost all areas compared to a control group of subjects from the Italian general population. A McCormick grade ≥ 3 and repeated surgeries were associated with a worse QOL (p = 0.006 and p = 0.017). CONCLUSIONS An early diagnosis of CEE is important because larger tumors are associated with recurrences and worse functional neurological outcomes. Surgery should be performed with the aim of achieving an en bloc GTR. The histological subtype was not directly associated with recurrences, but some of the features more commonly encountered in MPEs were. The outcomes are in most cases favorable, but the mean QOL perception is inferior to that of the general population.