Bailey Sarah Er, Ukoumunne Obioha C, Shephard Elizabeth A, Hamilton Willie
University of Exeter Medical School, Exeter.
NIHR CLAHRC South West Peninsula, University of Exeter Medical School, Exeter.
Br J Gen Pract. 2017 Jun;67(659):e405-e413. doi: 10.3399/bjgp17X691109.
Thrombocytosis (raised platelet count) is an emerging risk marker of cancer, but the association has not been fully explored in a primary care context.
To examine the incidence of cancer in a cohort of patients with thrombocytosis, to determine how clinically useful this risk marker could be in predicting an underlying malignancy.
A prospective cohort study using Clinical Practice Research Datalink data from 2000 to 2013.
The 1-year incidence of cancer was compared between two cohorts: 40 000 patients aged ≥40 years with a platelet count of >400 × 10/L (thrombocytosis) and 10 000 matched patients with a normal platelet count. Sub-analyses examined the risk with change in platelet count, sex, age, and different cancer sites.
A total of 1098 out of 9435 males with thrombocytosis were diagnosed with cancer (11.6%; 95% confidence interval [CI] = 11.0 to 12.3), compared with 106 of 2599 males without thrombocytosis (4.1%; 95% CI = 3.4 to 4.9). A total of 1355 out of 21 826 females with thrombocytosis developed cancer (6.2%; 95% CI = 5.9 to 6.5), compared with 119 of 5370 females without (2.2%; 95% CI = 1.8 to 2.6). The risk of cancer increased to 18.1% (95% CI = 15.9 to 20.5) for males and 10.1% (95% CI = 9.0 to 11.3) for females, when a second raised platelet count was recorded within 6 months. Lung and colorectal cancer were more commonly diagnosed with thrombocytosis. One-third of patients with thrombocytosis and lung or colorectal cancer had no other symptoms indicative of malignancy.
Thrombocytosis is a risk marker of cancer in adults; 11.6% and 6.2% cancer incidence in males and females, respectively, is worthy of further investigation for underlying malignancy. These figures well exceed the National Institute for Health and Care Excellence-mandated risk threshold of 3% risk to warrant referral for suspected cancer.
血小板增多症（血小板计数升高）是一种新出现的癌症风险标志物，但在初级保健环境中，这种关联尚未得到充分研究。
研究血小板增多症患者队列中的癌症发病率，以确定这种风险标志物在预测潜在恶性肿瘤方面的临床实用性。
一项前瞻性队列研究，使用2000年至2013年临床实践研究数据链的数据。
比较两个队列的癌症1年发病率：40000名年龄≥40岁、血小板计数>400×10⁹/L的患者（血小板增多症患者）和10000名血小板计数正常的匹配患者。亚组分析研究了血小板计数变化、性别、年龄和不同癌症部位的风险。
9435名血小板增多症男性患者中，共有1098人被诊断患有癌症（11.6%；95%置信区间[CI]=11.0至12.3），而2599名无血小板增多症的男性患者中有106人（4.1%；95%CI=3.4至4.9）。21826名血小板增多症女性患者中，共有1355人患癌症（6.2%；95%CI=5.9至6.5），而5370名无血小板增多症的女性患者中有119人（2.2%；95%CI=1.8至2.6）。当在6个月内记录到第二次血小板计数升高时，男性患癌风险增至18.1%（95%CI=15.9至20.5），女性增至10.1%（95%CI=9.0至11.3）。肺癌和结直肠癌在血小板增多症患者中更常被诊断出来。三分之一的血小板增多症合并肺癌或结直肠癌患者没有其他恶性肿瘤的症状。
血小板增多症是成年人患癌的风险标志物；男性和女性的癌症发病率分别为11.6%和6.2%，值得进一步调查潜在的恶性肿瘤。这些数字远远超过了英国国家卫生与临床优化研究所规定的3%风险阈值，该阈值是疑似癌症转诊的依据。
