BackgroundHistological transformation (HT) to diffuse large B‐cell lymphoma (DLBCL) is a common complication of follicular lymphoma (FL) and is usually associated with a dismal outcome. However, the survival rate of these patients has improved over the last 20 years with the introduction of rituximab. This study aimed to access the outcome of transformation to DLBCL (t‐DLBCL) from FL in a retrospective series that began after the widespread use of rituximab use. In addition, we also compared survival between t‐DLBCL and primary DLBCL (p‐DLBCL) in the same timeframe.MethodsWe utilized the Surveillance, Epidemiology, and End Results (SEER) database to identify patients with primary FL and patients with p‐DLBCL between 2000 and 2020. Patients who had a subsequent diagnosis of DLBCL at least 2 months after FL diagnosis were identified as t‐DLBCL.ResultsFinally, we identified 50,332 FL and 95,933 p‐DLBCL. With a median follow‐up of 119 months, 1631 patients developed t‐DLBCL. The median time from FL diagnosis to t‐DLBCL was approximately 4 years. The post‐transformation survival (PTS) rate at 5 years was 49.6%, with a median PTS of 56 months. Older age, advanced stage, and early transformation were associated with worse PTS. Furthermore, t‐DLBCL receiving chemotherapy or combined modality as initial therapy before HT was also associated with worse PTS, while the result was inverse when taking the impact of initial management strategy at HT into account. Taking t‐DLBCL and p‐DLBCL as a whole, comparable survival was observed between p‐DLBCL and t‐DLBCL receiving radiation or watch‐and‐wait as initial therapy prior to HT.ConclusionThe outcome of t‐DLBCL in the rituximab era was better than historical series before the rituximab era. Due to the good prognosis, we did not recommend autologous stem cell transplantation for t‐DLBCL receiving watch‐and‐wait or radiation as initial therapy before HT.

中文翻译：

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利妥昔单抗时代滤泡性淋巴瘤转化为弥漫性大 B 细胞淋巴瘤的结果：一项基于人群的研究

背景组织学转化 (HT) 为弥漫性大 B 细胞淋巴瘤 (DLBCL) 是滤泡性淋巴瘤 (FL) 的常见并发症，通常与令人沮丧的结果相关。然而，随着利妥昔单抗的引入，这些患者的生存率在过去 20 年中有所提高。本研究旨在通过广泛使用利妥昔单抗后开始的回顾性系列研究，了解从 FL 转化为 DLBCL (t-DLBCL) 的结果。此外，我们还比较了同一时间范围内 t-DLBCL 和原发性 DLBCL (p-DLBCL) 的生存率。方法我们利用监测、流行病学和最终结果 (SEER) 数据库来识别原发性 FL 患者和 p-DLBCL 患者2000 年至 2020 年间。在 FL 诊断至少 2 个月后再次诊断为 DLBCL 的患者被确定为 t-DLBCL。结果最终，我们确定了 50,332 例 FL 和 95,933 例 p-DLBCL。中位随访时间为 119 个月，1631 名患者发展为 t-DLBCL。从 FL 诊断到 t-DLBCL 的中位时间约为 4 年。 5 年转化后生存率 (PTS) 为 49.6%，中位 PTS 为 56 个月。年龄较大、晚期和早期转化与较差的 PTS 相关。此外，在 HT 之前接受化疗或联合治疗作为初始治疗的 t-DLBCL 也与较差的 PTS 相关，而如果考虑到 HT 时初始治疗策略的影响，结果则相反。将 t-DLBCL 和 p-DLBCL 作为一个整体，在 HT 之前接受放疗或观察等待作为初始治疗的 p-DLBCL 和 t-DLBCL 之间观察到相当的生存率。结论 利妥昔单抗时代 t-DLBCL 的结果是比利妥昔单抗时代之前的历史系列更好。由于预后良好，我们不建议对接受观察等待或放疗的 t-DLBCL 进行自体干细胞移植作为 HT 前的初始治疗。