Prognostic Factors And Appropriate Postoperative Treatment For CNS-PNET:a SEER-based Analysis

Background and PurposeCentral nervous system primitive neurotodermal tumor(CNS-PNET)is an extremely rare and highly invasive malignancy originates from primitive neuroepithelium cells and has the potential of multi-directional differentiation,which carries a very poor prognosis due to the rapidly growth rate and prone to relapse and metastasis.The incidence of CNS-PNET in the world is extraordinarily low,not only lack of sufficient cases for analysis,large-scale clinical trials are also difficult to carry out,and the progress in treatment is very slow.Because of the histological similarity,patients with CNS-PNET are often treated with protocols designed for high-risk medulloblastoma patients,including surgery,postoperative radiotherapy and chemotherapy.However,the outcome of CNS-PNET patients is far worse than that of medulloblastoma,and the 5-years OS rate is less than 50%.Based on the available evidence of evidence-based medicine,the prognostic factors affecting the survival of CNS-PNET patients are not clearly defined,and the merits of various treatment modality need to be further clarified.Therefore,the purpose of this study was to identify the prognostic factors and explore the impact of different postoperative adjuvant treatments on CSS in CNS-PNET patients using SEER database,So as to provide a theoretical basis for determining the prognosis of patients,but also offer a reference for the choice of clinical treatment strategies.MethodsWe collected the clinical data of patients diagnosed with primary CNS-PNET from 1973 to 2016 through SEER(Surveillance,Epidemiology,and End Results),an authoritative cancer statistical database in the United States,including age,sex,race,insurance status,marital status,diagnosis confirmation,tumor location,tumor size,distant metastasis status,surgical information,postoperative radiotherapy,chemotherapy,follow-up data(survival time,survival status)and so on.Descriptive statistical analysis was used to show the baseline characteristics of patients and Pearson Chi-square test was used to calculate the differences among groups.Univariate and multivariate Cox proportional regression models were used to evaluate the correlation between clinical variables and OS and CSS.Kaplan-Meier survival curve was used to compare the effects of various postoperative adjuvant treatment on the prognosis of patients with CNS-PNET.The original data was preprocessed by Stata software,descriptive statistics was carried out by SPSS software,and data analysis and visualization are performed by R language software.ResultsA total of 934 patients with histologically confirmed CNS-PNET were included in this study,containing 647(69.8%)in the pediatric group and 287(30.2%)in the adult group.Multivariate Cox proportional regression model analysis suggested that age and the gross total resection(GTR)showed meaningful prognostic value for overall survival(OS)and cancer specific survival(CSS)as prognostic factors in both groups.Chemotherapy can reduce the risk of death and prolong survival in children with CNS-PNET,is an independent prognostic factor.The extent of tumor infiltration and postoperative radiotherapy is a independent prognostic factor affecting OS in adults with CNS-PNET.Survival analysis revealed that optimal adjuvant treatment,according to the extent of surgery resection,was distinct in children under 3 years.Here,chemotherapy alone had the greatest effect in those undergoing GTR and the best choice for those with PTR was radiotherapy combined with chemotherapy.However,in children older than 3 years and adults,only complete removal of tumor was associated with survival benefit.Postoperative adjuvant treatment was not significantly associated with survival.ConclusionIn those patients with CNS-PNET,significant predictive factors of survival were age and GTR.For children under 3 years,favorable postoperative treatment varied with the extent of surgery resection,chemotherapy alone had the greatest effect in those undergoing GTR and the best choice for those with PTR was radiotherapy combined with chemotherapy.However,among children more than 3 years and adults,full resection of the tumor is highly recommended.