Pathological characteristics of recurrent glioma and its prognosis analysis

Abstract

Objective To explore the pathological characteristics of recurrent glioma and its relationship with the patient′s prognosis. Methods A retrospective analysis was conducted on the clinical data of 54 patients with recurrent glioma treated at Neurosurgery Department, Sun Yat-sen University Cancer Center from August 2002 to December 2016. All patients underwent a second operation of tumor resection and postoperative pathological examinations including the World Health Organization (WHO) classification of the tumor, Ki-67 index, O6-methylguanine-DNA-methyltransferase (MGMT) status and isocitrate dehydrogenase 1 (IDH1) status. The histopathological features of recurrent samples were classified according to presence of necrosis and tumor cells as well as activity of tumor cells. The overall survival (OS) of patients was analyzed using the Kaplan-Meier method. The univariate and multivariate Cox regression analysis was further conducted to determine the clinical factors affecting OS in patients with recurrent glioma. Results Pathological test results in 54 patients were as follows: (1) In terms of WHO grade, there were 6 cases of grade Ⅱ(11.1%), 14 cases of grade Ⅲ(25.9%), 30 cases of grade Ⅳ(55.6%), and 4 cases (7.4%) without tumor cells. Compared with the first operation, there was no change in the WHO grade in 32 patients (59.2%), 7 (13.0%) had lower WHO tumor grades and 15 (27.8%) had higher grades; (2) In terms of Ki-67 index, out of 32 cases undergoing two times of testing, 15 cases had decreased Ki-67 index, 14 had increased Ki-67 index, and 3 cases had unchanged index; (3) In terms of IDH1 status, out of 29 cases undergoing two times of relevant tests, 9 cases were mutant and 20 were wild type; (4) In terms of MGMT status: out of 8 cases undergoing two times of relevant tests, 6 cases consisting of 3 cases with positive expression and 3 cases with negative expression had no change, and the remaining 2 changed from positive expression in the first test to negative expression in the second test; (5) In terms of pathological classification, 4 cases were necrosis type, 20 were mixed type, and 30 were active type. The follow-up time of 54 patients was 16.1±3.2 months (1.3-160.3 months). The Kaplan-Meier analysis showed a median OS of 14.4 months in 54 patients. The result of multivariate Cox regression analysis showed that high WHO grade of recurrence tumor (HR=2.80, 95% CI: 1.42-5.53, P<0.01) and absence of postoperative radiotherapy (HR=4.05, 95% CI: 1.41-11.64, P=0.01) were independent risk factors affecting OS in patients with recurrent glioma. Conclusions This preliminary study has suggested that recurrent gliomas might have changed pathological results revealed post re-surgery, and low WHO tumor grade and postoperative radiotherapy seem to be predictive factors of better prognosis. Key words: Glioma; Recurrence; Pathology; Prognosis