滤泡性淋巴瘤（FL）的组织学转化（HT）是一个至关重要的生物学事件。本研究旨在评估基于人群的大规模队列中 FL 转化为弥漫性大 B 细胞淋巴瘤的发病率、临床特征、预后以及 HT 时间对生存的影响。监测、流行病学和最终结果数据库。使用血液恶性肿瘤研究网络 FL 队列和亚里士多德研究 FL 队列来评估外部有效性。在监测、流行病学和最终结果数据库的 44,127 例 FL 病例中，1311 例经病理证实记录为弥漫性大 B 细胞转化淋巴瘤。 FL 诊断后 5 年、10 年和 15 年的 HT 累积发生率估计分别为 1.19%、2.93% 和 5.01%。与没有 HT 的患者相比，患有 HT 的患者的总体生存率和癌症特异性生存率显着较差。早期 HT（FL 诊断后 48 个月内发生 FL [TOD48]）是 HT 患者不良总生存率的独立预测因素，无论转变前的治疗方式如何。 TOD48 的不良预后效应在血液恶性肿瘤研究网络队列和亚里士多德研究队列中得到了验证。年龄较大（>75 岁）和诊断时 FL 内的 B 症状是 TOD48 的独立危险因素。此外，构建了TOD48与滤泡性淋巴瘤国际预后指数（TOD48-FLIPI）相结合的新型预后模型，并验证了其风险分层。TOD48是HT的风险指标，提出了HT患者的新型预后模型“TOD48-FLIPI” .© 2024 美国癌症协会。

The histological transformation (HT) of follicular lymphoma (FL) is a crucial biological event. The study aimed to evaluate the incidence, clinicial characteristics, prognosis and impact of HT time on survival of FL transforming to diffuse large B-cell lymphoma in population-based large-scale cohorts.A retrospective cohort study of FL with HT was performed in the Surveillance, Epidemiology, and End Results database. The Hematological Malignancy Research Network FL cohort and Aristotle study FL cohort were used to assess the external validity.Among 44,127 FL cases from the Surveillance, Epidemiology, and End Results database, 1311 cases were pathology-proven recorded to transform to diffuse large B-cell lymphoma. The cumulative rates of HT at 5, 10, and 15 years after FL diagnosis were estimated to be 1.19%, 2.93%, and 5.01%, respectively. Significantly worse overall survival and cancer-specific survival were exhibited in patients with HT than those without HT. Early HT (transformation of FL within 48 months after FL diagnosis [TOD48]) was an independent predictor for adverse overall survival of HT patients, regardless of treatment modalities before transformation. The adverse prognostic effect of TOD48 was validated in the Hematological Malignancy Research Network cohort and Aristotle study cohort. Older age (>75 years) and B symptoms within FL at diagnosis were the independent risk factors of TOD48. Furthermore, a novel prognostic model combining TOD48 with Follicular Lymphoma International Prognostic Index (TOD48-FLIPI) was constructed and validated for risk stratification.TOD48 was a risk indicator of HT, and the novel prognostic model "TOD48-FLIPI" for HT patients was proposed.© 2024 American Cancer Society.