Abstract: Background: Central nervous system(CNS) tumors in infancy are rare and very few reports are available in China. Objective: To investigate the clinical features, pathological spectrum, survival outcome and prognostic factors in infants with CNS tumors. Design: Retrospective cohort study. Methods: The starting point of the cohort was from June 2011 to December 2019, and infants under the age of 12 months with the initial diagnosis of primary CNS tumors were enrolled and treated by a multidisciplinary model of surgery in combination with chemotherapy. The end of followup was March 31, 2020. Metastasis, tumor site, tumor grade, tumor diameter, degree of resection, and chemotherapy were used as prognostic factors for overall survival (OS) and eventfree survival (EFS). Main outcome measures: Prognostic factors for OS and EFS. Results: Among 52 patients included in this study, there were 36 males and 16 females. The median age of onset was 6.7 (range, 012) months, less than 6 months in 18 cases, including 2 cases of neonatal onset. Thirtythree cases were supratentorial, 17 cases were infratentorial, and 2 cases were in spinal cord. The tumor diameter was <5 cm in 26 cases, ≥ 5 cm in 19 cases , and unknown in 7 cases. A total of 44 cases (84.6%) underwent surgical resection of tumors with 39 cases (89%) under gross total/ near total resection, five cases under partially resection, and 1 case of noninvasive brain biopsy. At the time of diagnosis, 4 patients experienced metastasis (M+). Eight cases gave up due to economic reasons or high surgical risk and all died 0.9 (01.24) months after diagnosis. Twentyfour cases of lowgrade tumors (WHO grade I+Ⅱ) and 20 highgrade tumors (WHO grade Ⅲ+Ⅳ) were confirmed. There were 17 cases of choroid plexus tumor, 11 cases of glioma, 13 cases of embryonal tumors, 2 cases of atypical teratoma, and 1 case of craniopharyngioma. Twentyfour patients (46%) received chemotherapy after surgery among whom eleven cases relapsed or experienced progression including 10 cases of death, and 13 cases were in eventfree survival and including 1 case of survival with events. Among twenty cases (46%) who received no chemotherapy, 1 case died after relapse or progression, 19 cases were in eventfree survival. Multivariate COX regression analysis demonstrated that the hazardratio of OS and EFS of nongross total tumor resections was 5.7 （95% CI：1.408~23.115） and 5.1（95% CI：1.260~20.731）compared with gross total /near total tumor resections; 18.0（95%CI：2.222~146.5897）and 8.3（95%CI：1.687~40.530）were for high WHO grade tumors compared with lowgrade tumors; 4.2（95%CI：1.563~11.291）and 4.9（95%CI：1.996~12.216）were for infratentorial tumors compared with supratentorial cases. Conclusion: Primary lowgrade tumors in infancy have good prognosis. Highgrade tumors such as atypical teratoma /rhabdoid tumors, embryonic tumors with multiple rosettes and pineoblastoma have poor prognosis. Nongross total /near total tumor resections, highgrade tumor and infratentorial tumor location are poor prognostic factors for OS and EFS.

Key words: Central nervous system tumor, Infant, Treatment, Multicenter study