Systom review on prognostic factors of surgical treatment for grade Ⅱ spinal ependymoma patients

English Keywords:Spinal ependymoma  Surgery  Influencing factors  Progression free survival  Overall survival  Survival analysis

English Abstract:

  【Abstract】 Objectives: To identify the prognostic factors of patients with grade Ⅱ spinal ependymoma, and to estimate the survival outcomes. Methods: PubMed, Embase, Ovid, CNKI and Wanfang databases were searched by two investigators. The search was conducted in the time period from database construction to November 2017. The search terms were "spinal cord ependymoma" or other histological classifications of Grade Ⅱ ependymomas. Inclusion criteria were: single case information was presented, and diagnosis was confirmed by pathological examination; all the patients were treated by surgery. Exclusion criteria were: primary lesion was extramedullary; studies did not focus on histological classifications or data were not available; the follow-up data were not referenced; nonsurgical treatment. Data of patient characteristics such as age, sex, complaints, location and length of tumor, extent of resection, strategy of adjuvant treatment, recurrence or progression of disease, mortality, time to recurrence or death, and follow-up time were collected. The ages of the patients were categorized into two groups: age ＜18 and age ≥18. The extents of resection were divided into three groups: total resection(TR), subtotal resection(STR) and biopsy & decompression. The pathological classifications were divided into six groups: cellular ependymoma, papillary ependymoma, clear cell ependymoma, tanycytic ependymoma, giant cell ependymoma, typical Grade Ⅱ ependymoma(the patients whose histological classifications of Grade Ⅱ ependymoma were not stated). The adjuvant treatments were divided into two groups: adjuvant treatment(AT) and no adjuvant treatment(NAT). Univariate Kaplan-Meier analysis was carried out to identify variables associated with progression free survival(PFS) and overall survival(OS). Multivariate Cox regression was performed to estimate hazard ratios(HR) with 95% confidence intervals(95%CI). Statistical analysis was performed by SPSS version 17.0. Statistical significance was defined as P<0.05. Results: A total of 35 studies was identified, including 154 cases of Grade Ⅱ spinal ependymoma consisted of 82 males and 72 females. The mean of age, duration of symptoms, follow-up time, tumor length, recurrence time, PFS, OS was 35.7±17.2 years, 22.3±26.7 months, 56.6±53.1 months, 4.6±3.7 vertebra levels, 35.0±38.4 months, 44.7±53.1 months, respectively. Univariate Kaplan-Meier analysis showed no significant difference(P>0.05) including: PFS and OS between <18 years group and >18 years group; PFS and OS between clear cell ependymoma or tanycytic ependymoma and classic Grade Ⅱ ependymoma; PFS between giant cell ependymoma and classic Grade Ⅱ ependymoma; OS between cellular ependymoma or papillary ependymoma and classic Grade Ⅱ ependymoma; PFS and OS between TR group or STR group and decompression & biopsy group; OS between AT group and NAT group. Those with statistical differences included: patients with cellular ependymoma, papillary ependymoma or adjuvant therapy would have shorter PFS than others(P<0.001, P=0.007, P<0.001, respectively); patients with giant cell ependymoma would have shorter overall survival than others(P=0.001); PFS in AT group was better than NAT group(P<0.001). Cox regression analysis showed no significant difference(P>0.05) including: OS in cellular ependymoma, papillary ependymoma, clear cell ependymoma, tanycytic ependymoma and classic Grade Ⅱ ependymoma; OS between TR group and STR group; OS between AT group and NAT group. Those with statistical differences included: cellular ependymoma(HR=7.784, 95%CI 3.307-18.318, P<0.001), papillary ependymoma(HR=10.536, 95%CI 2.116-52.461, P=0.004) and AT group(HR=0.224, 95%CI 0.107-0.468, P<0.001) had higher progression risk than others; giant cell ependymoma had a higher mortality risk than others(HR=31.673, 95%CI 2.771-361.978, P=0.005); there was better PFS in AT group compared to NAT group(HR=0.224, 95%CI 0.107-0.468, P<0.001). Conclusions: The pathological subtype of Grade Ⅱ spinal ependymoma is important factor influencing surgical outcomes. Cellular ependymoma, papillary ependymoma, adjuvant therapy are associated with shorter PFS. Giant cell ependymoma has shorter overall survival than others. Resection scope does not significantly affect the therapeutic effect. Adjuvant therapy can not improve outcomes after surgical treatment.