A predictive model for aggressive non-Hodgkin's lymphoma was developed to improve the identification of patients with different long-term prognoses. The model, based on clinical characteristics before treatment, includes age, tumor stage, serum lactate dehydrogenase (LDH) concentration, performance status, and number of extranodal disease sites. It identifies four risk groups with predicted five-year survival rates of 73%, 51%, 43%, and 26% for all ages, and 83%, 69%, 46%, and 32% for patients 60 years or younger. The model outperforms the Ann Arbor classification in predicting long-term survival. The international index and age-adjusted international index are recommended for future therapeutic trials and individual patient treatment decisions. The model considers factors such as tumor stage, LDH level, and performance status, and identifies risk groups based on the number of these factors. The survival curves and death rates for the four risk groups are shown in the study. The model is applicable to all patients and younger patients, with the age-adjusted index for younger patients. The study highlights the importance of identifying high-risk patients for experimental therapies and the need for accurate prognostic models to guide treatment decisions. The model is based on data from 2031 patients and 1274 younger patients, and the results are validated in separate samples. The study also discusses the significance of age in prognosis and the importance of identifying patients at increased risk of relapse after complete remission. The model is expected to improve the accuracy of prognostic assessments and guide therapeutic decisions in aggressive non-Hodgkin's lymphoma.A predictive model for aggressive non-Hodgkin's lymphoma was developed to improve the identification of patients with different long-term prognoses. The model, based on clinical characteristics before treatment, includes age, tumor stage, serum lactate dehydrogenase (LDH) concentration, performance status, and number of extranodal disease sites. It identifies four risk groups with predicted five-year survival rates of 73%, 51%, 43%, and 26% for all ages, and 83%, 69%, 46%, and 32% for patients 60 years or younger. The model outperforms the Ann Arbor classification in predicting long-term survival. The international index and age-adjusted international index are recommended for future therapeutic trials and individual patient treatment decisions. The model considers factors such as tumor stage, LDH level, and performance status, and identifies risk groups based on the number of these factors. The survival curves and death rates for the four risk groups are shown in the study. The model is applicable to all patients and younger patients, with the age-adjusted index for younger patients. The study highlights the importance of identifying high-risk patients for experimental therapies and the need for accurate prognostic models to guide treatment decisions. The model is based on data from 2031 patients and 1274 younger patients, and the results are validated in separate samples. The study also discusses the significance of age in prognosis and the importance of identifying patients at increased risk of relapse after complete remission. The model is expected to improve the accuracy of prognostic assessments and guide therapeutic decisions in aggressive non-Hodgkin's lymphoma.