{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,14]],"date-time":"2026-09-14T21:30:19Z","timestamp":1789421419946,"version":"build-2803163510"},"reference-count":27,"publisher":"Wiley","issue":"24","license":[{"start":{"date-parts":[[2009,10,5]],"date-time":"2009-10-05T00:00:00Z","timestamp":1254700800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cancer"],"published-print":{"date-parts":[[2009,12,15]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>BACKGROUND:<\/jats:title><jats:p>Advanced age and a history of thrombosis were well\u2010established risk factors for thrombosis in essential thrombocythemia (ET) and polycythemia vera (PV); cytoreductive therapy was indicated in their presence. Recent studies have suggested leukocytosis as an additional risk factor; however, such an association would be treatment\u2010relevant in the context of low\u2010risk disease.<\/jats:p><\/jats:sec><jats:sec><jats:title>METHODS:<\/jats:title><jats:p>In this retrospective study, a Cox proportional hazards model was used to determine the impact of various clinical and laboratory variables, including leukocytosis, on thrombosis\u2010free survival (TFS). Arterial\u2010specific or venous\u2010specific TFS curves for different leukocyte count\u2010defined risk groups were constructed by the Kaplan\u2010Meier method and compared using the log\u2010rank test.<\/jats:p><\/jats:sec><jats:sec><jats:title>RESULTS:<\/jats:title><jats:p>A total of 407 low\u2010risk patients (254 with ET and 153 with PV) were considered. After a respective median follow\u2010up of 104 months and 130 months, respectively, 47 (19%) patients with ET and 41 (27%) with PV experienced a total of 55 (41 arterial and 14 venous) and 46 (22 arterial and 24 venous) thrombotic events, respectively. Leukocytosis at the time of diagnosis, defined by a cutoff level of either 15 or 9.4 \u00d7 10<jats:sup>9<\/jats:sup>\/L, did not appear to be predictive of either arterial or venous thrombosis during follow\u2010up; similar results were obtained when analysis was restricted to patients with platelet counts of &lt;1000 \u00d7 10<jats:sup>9<\/jats:sup>\/L. Instead, advanced age was found to be significantly associated with arterial thrombosis in patients with PV and higher hemoglobin level with venous thrombosis in patients with ET.<\/jats:p><\/jats:sec><jats:sec><jats:title>CONCLUSIONS:<\/jats:title><jats:p>In the current retrospective study, leukocytosis at diagnosis did not appear to influence the risk of thrombosis in either ET or PV. However, a prospective study is required before leukocytosis is taken into account during treatment decisions in these disorders. Cancer 2009. \u00a9 2009 American Cancer Society.<\/jats:p><\/jats:sec>","DOI":"10.1002\/cncr.24664","type":"journal-article","created":{"date-parts":[[2009,10,5]],"date-time":"2009-10-05T13:32:13Z","timestamp":1254749533000},"page":"5740-5745","source":"Crossref","is-referenced-by-count":58,"title":["Leukocytosis at diagnosis and the risk of subsequent thrombosis in patients with low\u2010risk essential thrombocythemia and polycythemia vera"],"prefix":"10.1002","volume":"115","author":[{"given":"Naseema","family":"Gangat","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexandra P.","family":"Wolanskyj","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Susan M.","family":"Schwager","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Curtis A.","family":"Hanson","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ayalew","family":"Tefferi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2009,10,5]]},"reference":[{"key":"e_1_2_6_2_2","doi-asserted-by":"publisher","DOI":"10.4065\/78.2.174"},{"key":"e_1_2_6_3_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2141.2007.06674.x"},{"key":"e_1_2_6_4_2","doi-asserted-by":"publisher","DOI":"10.4065\/81.2.159"},{"key":"e_1_2_6_5_2","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.1990.8.3.556"},{"key":"e_1_2_6_6_2","doi-asserted-by":"publisher","DOI":"10.1182\/blood-2006-09-046342"},{"key":"e_1_2_6_7_2","first-page":"215","article-title":"Practice guidelines for the therapy of essential thrombocythemia. 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