Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Department of Dermatology, Massachusetts General Hospital, Boston.
JAMA Dermatol. 2022 Jul 1;158(7):791-795. doi: 10.1001/jamadermatol.2022.1562.
Although pruritus is common in patients with hematologic cancers, it is unknown whether patients with undifferentiated pruritus have higher risk of developing hematologic cancer. Furthermore, it is unclear whether serum lactate dehydrogenase (LDH) level, commonly ordered for cancer workup, has diagnostic utility in patients with pruritus.
To assess the risk of hematologic cancer and the diagnostic utility of LDH level in patients with undifferentiated pruritus.
DESIGN, SETTING, AND PARTICIPANTS: This retrospective population-level cohort analysis was conducted using the TriNetX Research Network, a global health records database encompassing more than 69 million patients, from 2002 to 2020. The study included 327 502 eligible patients diagnosed with unspecified pruritus, excluding those with existing chronic pruritic dermatoses or systemic diseases known to cause pruritus, along with 327 502 matched controls.
Development of hematologic cancer within 1 year, 5 years, and 10 years following unspecified pruritus diagnosis.
Primary study outcomes were 1-year, 5-year, and 10-year relative risks (RRs) for development of 9 hematologic cancers in patients with pruritus compared with control patients. Secondary outcomes were 1-year, 5-year, and 10-year RRs for any hematologic cancer at different LDH cutoffs (250 U/L and 500 U/L).
After matching, the pruritus and control cohorts each had 327 502 patients (68.1% female patients; 0.4% American Indian or Alaska Native patients; 3.5% Asian patients; 22.2% Black patients; 0.1% Native Hawaiian or Pacific Islander patients; 59.3% White patients; mean [SD] age, 42.2 [22] years). Patients with pruritus had increased 1-year risk of Hodgkin lymphoma (RR, 4.42; 95% CI, 2.83-6.88), myeloid leukemia (RR, 2.56; 95% CI, 1.79-3.67), multiple myeloma (RR, 2.38; 95% CI, 1.66-3.41), non-Hodgkin lymphoma (RR, 2.35; 95% CI, 1.96-2.82), monoclonal gammopathy (RR, 1.90; 95% CI, 1.55-2.32), myelodysplastic syndrome (RR, 1.74; 95% CI, 1.14-2.64), and lymphocytic leukemia (RR, 1.47; 95% CI, 1.07-2.02). After 12 months, the cancer risk was comparable with that of controls. Patients with pruritus had increased LDH levels, which were not associated with increased hematologic cancer risk.
In this cohort study, the RR of hematologic cancer in patients with undifferentiated pruritus was highest in the first 12 months, and LDH level had limited diagnostic utility in these patients. Clinicians should consider a thorough review of symptoms and assessment of cancer risk factors when deciding on workup for patients presenting with undifferentiated pruritus.
尽管瘙痒是血液系统癌症患者常见的症状，但目前尚不清楚患有未分化瘙痒的患者是否具有更高的患血液系统癌症的风险。此外，目前尚不清楚在患有瘙痒的患者中，常规用于癌症检查的血清乳酸脱氢酶（LDH）水平是否具有诊断效用。
评估未分化瘙痒患者患血液系统癌症的风险和 LDH 水平的诊断效用。
设计、设置和参与者：这是一项使用 TriNetX 研究网络进行的回顾性人群队列分析，该网络是一个包含超过 6900 万患者的全球健康记录数据库，涵盖了 2002 年至 2020 年的数据。研究纳入了 327502 名符合条件的患有未明确瘙痒的患者，排除了那些患有现有慢性瘙痒性皮肤病或已知可引起瘙痒的系统性疾病的患者，以及 327502 名匹配的对照患者。
瘙痒诊断后 1 年、5 年和 10 年内血液系统癌症的发展情况。
主要研究结局是与对照患者相比，瘙痒患者在 1 年内、5 年内和 10 年内发生 9 种血液系统癌症的相对风险（RR）。次要结局是在不同 LDH 截断值（250 U/L 和 500 U/L）下，瘙痒患者在 1 年内、5 年内和 10 年内发生任何血液系统癌症的 RR。
在匹配后，瘙痒组和对照组各有 327502 名患者（68.1%为女性患者；0.4%为美洲印第安人或阿拉斯加原住民患者；3.5%为亚洲患者；22.2%为黑人患者；0.1%为夏威夷原住民或太平洋岛民患者；59.3%为白人患者；平均[SD]年龄为 42.2[22]岁）。瘙痒患者在 1 年内患霍奇金淋巴瘤的风险增加（RR，4.42；95%CI，2.83-6.88）、髓样白血病（RR，2.56；95%CI，1.79-3.67）、多发性骨髓瘤（RR，2.38；95%CI，1.66-3.41）、非霍奇金淋巴瘤（RR，2.35；95%CI，1.96-2.82）、单克隆丙种球蛋白病（RR，1.90；95%CI，1.55-2.32）、骨髓增生异常综合征（RR，1.74；95%CI，1.14-2.64）和淋巴细胞白血病（RR，1.47；95%CI，1.07-2.02）。在 12 个月后，癌症风险与对照组相当。瘙痒患者的 LDH 水平升高，但与血液系统癌症风险增加无关。
在这项队列研究中，患有未分化瘙痒的患者患血液系统癌症的 RR 在最初的 12 个月内最高，LDH 水平在这些患者中诊断效用有限。当决定对出现未分化瘙痒的患者进行检查时，临床医生应考虑对症状进行全面审查并评估癌症风险因素。
