Centre for Pharmacoepidemiology, Department of Medicine, Solna, Karolinska Institutet, Sweden.
Department of Medical Science Haematology, Uppsala University, Uppsala, Sweden.
Cancer Epidemiol. 2020 Dec;69:101806. doi: 10.1016/j.canep.2020.101806. Epub 2020 Sep 15.
Immune thrombocytopenia (ITP) is an autoimmune disease treated with immunosuppressive agents, thrombopoietin receptor agonists, immunomodulation drugs and/or splenectomy. Patients with ITP have been found to have increased risk ofhematological malignancies. Studies investigating stomach/liver cancer are contradictory and the risk of developing other solid tumors is largely unknown. We aimed at estimating risk of overall and organ-specific cancers in patients with primary ITP.
The study population was Swedish patients with at least one ITP diagnosis recorded in the National Patient Register and a 1:10 matched comparison cohort from the population. The study period covers 1997-2016. The Cancer Register and the Cause of Death Register provided data on malignancies and deaths, respectively. Primary ITP was identified using an established algorithm. We used time-split Cox models to estimate hazard ratios (HRs) with 95 % confidence intervals (CIs), adjusted for age, sex, index-year, county, income, education, Charlson score and number of in- and outpatient contacts.
In total 66,134 individuals were included in the study. Patients with ITP had higher risk of gastro-intestinal, skin (all morphologies), lymphoid and hematological cancers. Adjusted HR (95 % CI) for cancer was 1.37 (1.27-1.48), with highest risk during the first year, but with increased risk remaining for up to 20 years for men. For women, the overall risk was increased during the first year, HR (95 % CI) 2.00 (1.55-2.60). A significantly increased liver cancer risk was seen up to 9 years after diagnosis.
Patients with primary ITP have higher risk of cancer than the population. The observed increased risk does not seem to be solely due to surveillance bias, but might be associated with ITP or its treatments. Treating hematologists need to have high index of suspicion for cancer.
免疫性血小板减少症（ITP）是一种自身免疫性疾病，采用免疫抑制剂、血小板生成素受体激动剂、免疫调节药物和/或脾切除术进行治疗。ITP 患者被发现有更高的血液恶性肿瘤风险。研究表明胃癌/肝癌的风险是相互矛盾的，而其他实体肿瘤的风险则知之甚少。我们旨在评估原发性 ITP 患者的总体和器官特异性癌症风险。
该研究人群为瑞典患者，其国家患者登记册中至少有一次 ITP 诊断记录，且与 1:10 匹配的人群对照队列来自于该登记册。研究期间为 1997 年至 2016 年。癌症登记册和死因登记册分别提供了恶性肿瘤和死亡数据。使用既定算法识别原发性 ITP。我们使用时间分割 Cox 模型来估计风险比（HR）和 95%置信区间（CI），调整了年龄、性别、指数年、县、收入、教育、Charlson 评分和门诊和住院接触次数。
总共纳入了 66134 名患者。ITP 患者患有胃肠道、皮肤（所有形态）、淋巴和血液恶性肿瘤的风险更高。调整后的癌症 HR（95%CI）为 1.37（1.27-1.48），男性的最高风险出现在第一年，但在长达 20 年的时间里风险仍然增加。对于女性，总体风险在第一年增加，HR（95%CI）为 2.00（1.55-2.60）。诊断后 9 年内肝癌风险显著增加。
与普通人群相比，原发性 ITP 患者癌症风险更高。观察到的风险增加似乎并非仅仅是由于监测偏差，而是可能与 ITP 或其治疗有关。治疗血液病的医生需要对癌症保持高度怀疑。
