Lijun Shen,1,2* Miao Mo,2,3* Leon Jia,4 Huixun Jia,2,3 Qingguo Li,2,5 Lei Liang,2,5 Debing Shi,2,5 Zhen Zhang,1,2 Sanjun Cai,2,5 Xinxiang Li,2,5 Ji Zhu1,2 1Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China; 2Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China; 3Department of Cancer Prevention, Fudan University Shanghai Cancer Center, Shanghai, China; 4Virginia Commonwealth University, Richmond, VA, USA; 5Department of Colorectal Surgery, Fudan University Shanghai Cancer Center, Shanghai, China *These authors contributed equally to this work Purpose: To investigate the association of age and sex on survival in non-metastatic colorectal cancer (CRC) patients and to identify groups at high risk for poor outcomes.Materials and methods: We performed a retrospective analysis of 5,047 non-metastatic CRC patients from 2008 to 2013. Data regarding age at diagnosis; gender; tumor site; tumor stage; differentiation; lymphatic, neural or vascular invasion; and survival outcomes were collected. Patients were stratified into 10-year age groups (≤35, 36–45, 46–55, 56–65, 66–75, >75) and then further analyzed in three age groups (≤35, 36–75, >75). Disease-free survival (DFS) and overall survival (OS) were evaluated using univariate and multivariate Cox regression models.Results: Of the 5,047 eligible patients, 41.3% were female. The tumor stages were balanced between the genders. In the female patients, the tumor stages were similarly distributed among the different age groups, while younger male patients were diagnosed with more advanced disease (P75 had shorter DFS than patients between 36 and 75 years old (HR=1.57 [1.03–2.38] and HR=1.51 [1.11–2.05, respectively]), while there was no difference in DFS between females ≤35 and those >75. For male patients, older age was associated with poorer OS after the same adjustment.Conclusion: Young female CRC patients (≤35 years old) had the poorest DFS and quite poor OS compared to the other age groups. This emphasizes the need for health care providers to have a heightened awareness and to conduct further research when caring for young female CRC patients. Keywords: colorectal cancer, young female, prognosis, China