Supplementary Material for: A Retrospective Chart Review of 809 Patients With Physician-Diagnosed Essential Thrombocythemia Receiving Cytoreductive Therapy in US Community Oncology Practices

Introduction: This analysis reports demographic and clinical characteristics of patients with physician-diagnosed essential thrombocythemia (ET) receiving cytoreductive therapy in US community clinical practice.

Methods: Patient characteristics, medical history, diagnostic test results, signs/symptoms, treatment patterns, and physician practice settings were extracted from medical charts for patients with physician-diagnosed ET receiving cytoreductive therapy.

Results: Among 809 patients (51.1% female; 75.4% White; median age, 69 years) from 50 community practices, 64.5% had physician-reported diagnosis per World Health Organization criteria. Only 48.8% underwent diagnostic bone marrow biopsies; 87.5% had JAK2 mutation testing. Among those tested, 512/708 (72.3%), 57/213 (26.8%), and 37/213 (17.4%) had JAK2, CALR, and MPL mutations, respectively. Of physician-assigned risk assessments, 41.8% were misclassifications based on data-derived risk assessment. Most patients (93.3%) received first-line hydroxyurea (HU) cytoreductive therapy. Discontinuations were primarily for intolerance (35.4%) and resistance (23.8%). Of those who discontinued, 65.9% received no subsequent therapy and had higher ET symptom rates at last visit versus patients continuing HU (48.8% vs 25.0%).

Conclusion: This study shows notable gaps in ET diagnosis and management. Half of patients were diagnosed without bone marrow biopsy, many received incorrect risk assignment, and the majority who discontinued HU received no subsequent therapy despite continued need.

引言：本分析报告了美国社区临床实践中，接受减细胞治疗（cytoreductive therapy）且经医师确诊的原发性血小板增多症（essential thrombocythemia, ET）患者的人口统计学与临床特征。

方法：针对经医师确诊ET并接受减细胞治疗的患者，从其病历中提取患者特征、病史、诊断检测结果、体征/症状、治疗模式以及医师执业环境等信息。

结果：纳入研究的809例患者来自50家社区医疗机构，其中女性占比51.1%，白人占比75.4%，中位年龄为69岁；64.5%的患者符合世界卫生组织（World Health Organization, WHO）制定的诊断标准并经医师确认诊断。仅48.8%的患者接受了诊断性骨髓活检，87.5%的患者完成了JAK2突变检测。在完成检测的患者中，分别有72.3%（512/708）、26.8%（57/213）及17.4%（37/213）检出JAK2、CALR及MPL突变。经医师进行的风险评估中，有41.8%的评估结果与基于数据推导的风险评估结果不符，即存在分类错误。绝大多数患者（93.3%）接受了一线羟基脲（hydroxyurea, HU）减细胞治疗。治疗中断的主要原因为药物不耐受（35.4%）与耐药（23.8%）。在中断治疗的患者中，65.9%未接受后续治疗，且末次随访时的ET相关症状发生率高于继续接受HU治疗的患者（48.8% vs 25.0%）。

结论：本研究揭示了ET诊疗过程中存在显著不足：近半数患者未行骨髓活检即获得诊断，大量患者存在风险分层错误，且多数停用HU的患者虽仍有治疗需求却未接受后续治疗。