摘要Objective:Due to the rarity of angioimmunoblastic T-cell lymphoma(AITL),very limited data concerning its incidence patterns and prognostic factors are available.This study aimed to explore the incidence,characteristics,survival outcomes,and prognostic factors of AITL.Methods:Age-adjusted incidence and temporal trends were calculated based on 1247 AITL patients from the National Cancer Institute's Surveillance,Epidemiology,and End Results(SEER)-13 database.A total of 1525 AITL patients from the SEER-18 database and 43 patients from our single center were included for survival analysis and nomogram construction.Results:The age-adjusted incidence for overall cohort was 0.123[95％confidence interval(CI),0.117-0.131)per 100 000 during 1992-2017.The overall incidence increased steeply at the rate of 15.3％(95％CI 11.0％-19.8％,P＜0.001)per year during 1992-2004,but remained stable during 2004-2017(P=0.200).Similar incidence trends were observed in age,sex,and stage subgroups.The final nomograms consisted of four variables:age at diagnosis,sex,Ann Arbor stage,and primary site.The concordance index(C-index)of the nomogram for 5-year overall survival prediction was 0.717,0.690 and 0.820 in the training cohort,validation cohort-1 and cohort-2,respectively.Regarding the disease-specific survival(DSS),the nomogram also demonstrated a good discrimination level,with the C-index for predicting the probability of DSS at 5 years of 0.716,0.682 and 0.813 for the three cohorts,respectively.The calibration displayed good concordance between the nomogram-predicted and actual observed outcomes.Conclusion:The age-adjusted incidence for AITL was low during 1992-2017.The incidence continuously increased during 1992-2004,but remained stable during 2004-2017.The nomograms as proposed may provide a favorable and accurate prognostic survival prediction in AITL.