Abstract: Objective Based on large sample data,to explore the 5-year mortality risk factors and 5-year mortality prediction model of young-onset rectal cancer patients.
Methods The clinical data of 6817 young-onset patients with rectal cancer were screened from the SEER clinical database of the National Cancer Institute,and then we evaluated the death-related risk factors in young patients with rectal cancer by univariate and multivariate regression analysis methods.Finally,the Nomogram prediction model was summarized and its accuracy was verified.
Results The results of Univariate and multivariate regression analysis showed that gender,marital status,Stage classification,T stage,N stage,radiotherapy,tumor size,and number of lymph nodes were the death-related risk in young-onset rectal cancer patients within 5 years.The Effective predictive performance of Nomogram prediction model was confirmed by the Area Under Curve of ROC(0.833，95%CI：0.823-0.843，P<0.001) and calibration curve for the risk of death of young-onset rectal cancer.
Conclusion The constructed nomogram chart can effectively predict the death-related risk of young-onset rectal cancer patients within 5 years,and has clinical guiding significance for the prognostic intervention of young-onset rectal cancer.

Key words: rectal cancer, Nomogram, risk of death, SEER database