Clinical relevance of thrombocytosis in primary care: a prospective cohort study of cancer incidence using English electronic medical records and cancer registry data.

  • S.E.R. B
  • O.C. U
  • E.A. S
 et al. 
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BACKGROUND: Thrombocytosis (raised platelet count) is an emerging risk marker of cancer, but the association has not been fully explored in a primary care context., AIM: 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., DESIGN AND SETTING: A prospective cohort study using Clinical Practice Research Datalink data from 2000 to 2013., METHOD: The 1-year incidence of cancer was compared between two cohorts: 40 000 patients aged >=40 years with a platelet count of >400 x 109/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., RESULTS: 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., CONCLUSION: 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., Copyright © British Journal of General Practice 2017.

Author-supplied keywords

  • *cancer incidence
  • *primary medical care
  • *thrombocytosis
  • adult
  • article
  • cancer registry
  • cancer risk
  • cohort analysis
  • colorectal cancer/ep [Epidemiology]
  • controlled study
  • electronic medical record
  • female
  • human
  • lung cancer/ep [Epidemiology]
  • major clinical study
  • male
  • medical record review
  • prospective study
  • risk assessment
  • sex ratio
  • thrombocyte count

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  • Bailey S.E.R.

  • Ukoumunne O.C.

  • Shephard E.A.

  • Sarah Er Bailey

  • Obioha C Ukoumunne

  • Elizabeth A Shephard

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