Abstract:  Abstract　Objective: To investigate the effects of clinical factors and treatment modalities on the prognosis of patients with peripheral primitive neuroectodermal tumor ( pPNET ). Methods: Clinical data of 33 patients with pPNET who underwent surgery or regional radiotherapy in our hospital were included in the retrospective study. Among the patients, 15 were male and 18 were female, with a median age of 17 years. Up to 21 of the 33 patients had primary foci in the trunk, whereas the other 12 patients suffered from primary tumors outside the trunk, specifically, 10 in the extremities and 2 in the scalp. Surgery was conducted on 25 of the patients, among which, 19 underwent radical operations and 6 received palliative surgery. Postoperative radiotherapy was performed on 8 of the 19 patients after radical surgery and on 1 of the 6 patients after the palliative surgery. Regional radiotherapy was performed in 3 of the 8 patients who did not undergo surgery. Of the 25 patients who underwent the surgery, 17 patients received postoperative chemotherapy and 5 patients received preoperative neoadjuvant chemotherapy. Systemic chemotherapy was conducted in 5 of the patients who failed to undergo the surgery. The Kaplan-Meier method and Cox regression were used for survival analysis, and a Chi-square test was used to analyze the incidence in the different groups. Results: The median survival time was 24 months ( range, 10-38 months ), and the 2-year survival rate was 36.4% for all patients. The local relapse rate was 31.6% for patients who underwent the radical surgery. The most common metastatic sites were the lungs and bones, with a 24.2% metastatic rate for all the groups. Univariate analysis demonstrated that both the primary lesion of the tumor ( P = 0.005 ) and the mode of surgery ( P = 0.001 ) affected overall survival, and postoperative radiotherapy ( P = 0.039 ) prolonged the survival time of patients after surgery. Multivariate analysis suggested that both the primary lesion of tumor ( P = 0.037 ) and the mode of operation ( P = 0.017 ) were the independent prognostic factors for survival. Conclusion: pPNETs have a very high degree of malignancy. The prognosis of the tumor is poor. The primary site of the tumors and the mode of operation are significantly correlated with overall survival. Postoperative radiotherapy may extend the survival time of patients who undergo surgery. Multivariate analysis suggests that the primary lesion and the mode of surgery are the independent prognostic factors for the patient survival.