Clinical Characteristics And Prognosis Of 52 Patients Of Primitive Neuroectodermal Tumors

Background and Objective Primitive neuroectodermal tumor(PNET)is a group of highly malignant tumors of small round cells derived from the neuroectoderm.The clinical manifestations are diverse and the pathological features are similar to those of other small round cell tumors.Therefore,the diagnosis is challenging.Classifications of this disease have been controversial in the past and the method recognized by most people is based on the tumor site.It can be divided into central primitive neuroectodermal tumors(c PNET)and peripheral primitive neuroectodermal tumors(p PNET).The former mainly refers to brain and spinal cord and p PNET is the tumors locating out of central nervous system and autonomic nervous system,such as soft tissue,bone,parenchymotous organs and so on.Primitive neuroectodermal tumors have the following characteristics:(1)low incidence rate;(2)The disease is malignant and easy to relapse and metastasis and the prognosis is relatively poor;(3)The patients are young and the age ranged from 10~20 years old.(4)Radiotherapy and chemotherapy are both effective treatment methods.According to the information of patients diagnosed in our hospital,we can find that the number of cases in recent years is gradually increased.Because the manifestations are diverse and the features of CT/MRI are lack of specificity along with the therapies are not uniform,the prognosis of PNET is different.In summary,timely diagnosis and standardized treatment regimen are both important and helpful for patients with PNET to improve the prognosis and the quality of life.Because of the improvements of diagnostic techniques and the treatment regimen in the past years,the prognosis of primitive neuroectodermal tumors has been changed.In order to deepen the understanding of PNET and improve the survival,the clinical data of patients diagnosed PNET in recent years was collected.The aim of this thesis is to summarize the clinical and pathological features along with the therapies and prognosis factors of the disease,thus providing new data for future reference.Methods 1 The medical data of patients with primary neuroectodermal tumors admitted in the first affiliated hospital of zhengzhou university from March 2011 to March 2015 were collected and all patients were diagnosed by pathological reports after operation or puncture biopsy.By screening,a total of 52 patients were enrolled.The morbidity characteristics included gender,age,tumors' site and stage,clinical manifestation and treatment regimen.Histopathologic features included the appearance under a light microscope or electron microscope,immunohistochemical staining and the genetic changes.2 The patients were followed-up by looking over imaging date or telephone,etc.The time to progression and overall survival should be recorded.The time of confirmed diagnosis was regarded as the beginning of follow-up visit and the patients' death or the last follow-up time was regarded as the endpoint.The deadline was August 30,2016.3 The prognosis and prognostic factors of primitive neuroectodermal tumors were analyzed by statistical methods.The primary target of this study was overall survival(OS)and the 1-year,2-year,3-year survival rates,progress free survival(PFS)were also regarded as indicators of prognosis.To analyze the factors of prognosis: Kaplan-Meier method was used for single factor analysis and the Log-rank method was used to test the significance of difference and multi-factor analysis was performed by COX regression.At the same time,to analyze the effects of prognostic factors on median OS.RESULTS 1 Characteristics of the disease The 52 patients of primitive neuroectodermal tumors in this group presented 30 cases of male,22 cases of female and the male to female ratio was 1.36:1.The age ranged from three to sixty-four years old and the median age was twenty-one years old.There were 25 patients younger than 18 years old and 27 patients older than 18 years old.There were 17 cases of central primitive neuroectodermal tumors,9 cases located in brain parenchyma and 8 cases located in spinal cord and 35 cases of peripheral primitive neuroectodermal tumors.Primary sites of tumors were divided into two parts: midline or pelvic(36 cases),non-midline(16 cases).The tumors in midline were those of located in central nervous system,paranasal sinus,thorax,adrenal gland,bladder,and so on and the tumors in non-midline were those of located in limb,neck and shoulder.There were 38 cases with stage I � II and 14 cases with stage III-IV.19 patients were treated with surgical resection and radiotherapy,along with chemotherapy;20 patients received surgical resection and chemotherapy;7 patients received surgical and radiotherapy.Tumors located in brain parenchyma mainly caused symptoms such as headache,nausea and vomiting due to the increased intracranial pressure.When the tumors were located in spinal cord,the patients always showed corresponding limbs sensory recession and activity disorder.Peripheral primitive neuroectodermal tumors mainly manifested as a increasing mass and the tumors occurred in solid organs induced the performance of organ dysfunction.2 Histopathological features Light microscope revealed that the tumor nodule was composed of uniform small round tumor cells,with scanty cytoplasm and round uniform nuclei.PNET was characterized by the performance of Homer-Wright structure.In this study,the positive rate of CD99 was 95.9% and that of FLI-1 was 95.0% and both of them were important immunohistochemical markers of PNET.In addition,Syn,NSE,vimentin and other neuroendocrine markers might have varying degrees of positive expression in PNET.Testing EWSR1 gene by FISH could improve the sensitivity and specificity of diagnosis and the positive rate of EWSR1 in this study was 85.7%.3 Prognosis In this study,progress free survival(PFS)of 52 cases of primitive neuroectodermal tumors ranged from 2months to 47 months and the overall survival(OS)ranged from 3 months to 63 months.Meanwhile,the median PFS was 10 months and the median OS was 18 months.The 1-,2-,3-year survival rates were 76.9%,42.6% and 17.7% respectively.Univariate survival analysis showed that OS was affected by the tumor location(midline or pelvic,non-midline),tumor stage and treatment options,regardless of the age and gender.Multivariate survival analysis indicated that tumor location,tumor stage and treatment modality were all independent factors influencing the prognosis of PNET.CONCLUSIONS 1 CD99 and FLI-1 are important immunohistochemical markers for the diagnosis of primitive neuroectodermal tumors.It is also significant to detect the EWSR1 gene by FISH.2 Tumor location,stage and treatment modality are independent prognostic factors for PNET.Prognosis of the patients who are locating in non-midline,stage I-II,and received comprehensive treatment including surgery,radiotherapy and chemotherapy is better.