Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Aug 2;4(8):e2120633.
doi: 10.1001/jamanetworkopen.2021.20633.

Incidence of Cancer Among Adults With Thrombocytosis in Ontario, Canada

Vasily Giannakeas  1   2   3 , Steven A Narod  1   2   4
Affiliations

Incidence of Cancer Among Adults With Thrombocytosis in Ontario, Canada

Vasily Giannakeas et al. JAMA Netw Open. .

Abstract

Importance: Individuals with newly diagnosed cancer often have a high platelet count (thrombocytosis). Whether thrombocytosis is associated with the presence of an undiagnosed cancer remains unknown.

Objective: To assess whether a new diagnosis of thrombocytosis is associated with a subsequent risk of cancer among adults.

Design, setting, and participants: This population-based retrospective cohort study was conducted using linked laboratory data from Ontario, Canada, from January 1, 2007, to December 31, 2017, with follow-up until December 31, 2018. The study cohort included adults aged 40 to 75 years on the date of a routine complete blood count (CBC) test (index test) who had a normal platelet count in the 2 previous years and no history of cancer. Data analysis was performed in December 2020.

Exposures: Exposed individuals were those with a platelet count greater than 450 × 109/L. Matched unexposed control individuals had a platelet count within the reference range (150 × 109/L to 450 × 109/L) reported within 30 days of the exposure.

Main outcomes and measures: Incident cancers within 5 years after diagnosis of thrombocytosis. Absolute and relative risks for cancer associated with thrombocytosis were estimated for all cancers and for cancers at specific sites.

Results: Of the 3 386 716 Ontario residents with a recorded routine CBC test result, 53 339 (1.6%) had thrombocytosis and a prior normal platelet count. Among individuals with thrombocytosis, the median age was 59.7 years (interquartile range, 50.2-67.4 years) and 37 349 (70.0%) were women. Among the 51 624 individuals with thrombocytosis included in the matched analysis, 2844 (5.5%) had received a diagnosis of a solid cancer in the 2-year follow-up period and 3869 (7.5%) had received a diagnosis within 5 years. The relative risk (RR) for developing any solid cancer within 2 years was 2.67 (95% CI, 2.56-2.79). Associations were found between thrombocytosis and cancers of the ovary (RR, 7.11; 95% CI, 5.59-9.03), stomach (RR, 5.53; 95% CI, 4.12-7.41), colon (RR, 5.41; 95% CI, 4.80-6.10), lung (RR, 4.41; 95% CI, 4.02-4.85), kidney (RR, 3.64; 95% CI, 2.94-4.51), and esophagus (RR, 3.64; 95% CI, 2.46-5.40).

Conclusions and relevance: In this cohort study, an increased platelet count was associated with an increased risk of cancer for at least 2 years. The results suggest that individuals with unexplained thrombocytosis should be offered screening for several cancers.

PubMed Disclaimer

Conflict of interest statement

Conflict of Interest Disclosures: None reported.

Figures

Figure 1.
Figure 1.. Study Design Criteria Among Matched Individuals
A normal platelet count was defined as between 150 × 109/L and 450 × 109/L (to convert to ×103/μL, divide by 1.0). aCondition applied to both patients with thrombocytosis and those with a normal platelet count.
Figure 2.
Figure 2.. Relative Risks for the Development of Incident Cancer Among Individuals With Thrombocytosis Compared With Control Individuals With a Normal Platelet Count by Time Elapsed Since Blood Test and Cancer Site
Data markers represent relative risks, with horizontal lines representing 95% CIs; marker size reflects the number of observed outcomes.
Figure 3.
Figure 3.. Relative Risks for the Development of Incident Cancer Among Individuals With Thrombocytosis Compared With Control Individuals With a Normal Platelet Count by Time Elapsed Since Blood Test and Cancer Site
Data markers represent relative risks, with horizontal lines representing 95% CIs; marker size reflects the number of observed outcomes. GI indicates gastrointestinal. “S” indicates data were suppressed to avoid potential identification of individuals when 5 or fewer values were obtained.
Figure 4.
Figure 4.. Relative Risks for the Development of Incident Cancer Among Individuals With Thrombocytosis Compared With Control Individuals With a Normal Platelet Count by Time Elapsed Since Blood Test and Cancer Site
Data markers represent relative risks, with horizontal lines representing 95% CIs; marker size reflects the number of observed outcomes.
See this image and copyright information in PMC

References

    1. Trousseau A. Lectures on Clinical Medicine. Vol 5. Hotel-Dieu Paris; 1865.
    1. Sproul E. Carcinoma and venous thrombosis: the frequency of association of carcinoma in the body and tail of the pancreas with multiple venous thrombosis. Am J Cancer. 1938;34(4):566–585. Accessed July 27, 2021. https://cancerres.aacrjournals.org/content/34/4/566
    1. Levin J, Conley CL. Thrombocytosis associated with malignant disease. Arch Intern Med. 1964;114(4):497-500. doi:10.1001/archinte.1964.03860100079008 - DOI - PubMed
    1. Khorana AA, Francis CW, Culakova E, Kuderer NM, Lyman GH. Thromboembolism is a leading cause of death in cancer patients receiving outpatient chemotherapy. J Thromb Haemost. 2007;5(3):632-634. doi:10.1111/j.1538-7836.2007.02374.x - DOI - PubMed
    1. Mezouar S, Frère C, Darbousset R, et al. . Role of platelets in cancer and cancer-associated thrombosis: experimental and clinical evidences. Thromb Res. 2016;139:65-76. doi:10.1016/j.thromres.2016.01.006 - DOI - PubMed

Publication types

Substances