Abstract: Background：Neuroblastoma is the most common extracranial solid tumor in children, and its clinical presentation and prognosis vary widely. Objective：To investigate the clinical features and prognostic analysis of different international neuroblastoma pathology classification in children with nonhighrisk neuroblastoma. Design：Retrospective cohort study. Methods：We retrospectively collected clinical data of nonhighrisk neuroblastoma children admitted to the medical oncology ward at Beijing Children's Hospital, Capital Medical University from March 2007 to December 2020. We divided the children into favorable histology（FH）group and unfavorable histology（UH）group according to the INPC classfication system. We analyzed the clinical features of the different international neuroblastoma pathology classification and performed a prognostic analysis. Survival analysis was carried out using the KaplanMeier method. Main outcome measures：3year and 5year overall survival(OS) and eventfree survival(EFS) rates. Results：A total of 445 children were included in the clinical data, including 313 children in the FH group. There were 164 cases (52.4%) younger than 18 months of age; the mediastinum was the most common site of origin (52.7%), with distant metastases in 52 cases (16.6%). In the UH group, there were 132 cases, with 25 cases (18.9%) younger than 18 months of age; the primary site was most common in the retroperitoneum (49.2%) and 10 cases (7.6%) had distant metastases. The differences in age distribution, primary site and incidence of distant metastases between the two groups were statistically significant, while the differences in gender, maximum diameter of the tumour and LDH level were not statistically significant. The median followup time was 34 (0.16166) months. The 3year EFS was 96.4% and 92% in the FH and UH groups, respectively, and 5year EFS was 95.4% and 87.8%, respectively, with statistically significant differences (χ2was 1.63 and 4.75, P was 0.046 and 0.029 , respectively). The 3year OS was 98.3% and 98.4% in the FH and UH groups, respectively, and 5year OS was 98% and 98.8%, respectively, with no statistically significant difference (χ2was 0.76 and 0.54, P was 1.53 and 0.82, respectively). Conclusions：Among children with nonhighrisk neuroblastoma, patients in the UH group are older than those in the FH group, have more retroperitoneal primary tumours and a lower incidence of distant metastases. Children with FH have better OS and EFS than children with UH and may be considered for less intensive chemotherapy.

Key words: Neuroblastoma, International Neuroblastoma Pathology Classification, favourable histology, Unfavorable histology, Prognostic analysis