Analysis of platelet count and new cancer diagnosis over a 10-year period

Individuals with cancer often have an elevated platelet count at the time of diagnosis. The extent to which an elevated platelet count is an indicator of cancer is unclear. A nested case-control study of 8,917,187 Ontario residents who had 1 or more routine complete blood count tests performed, found that an elevated platelet count was associated with a diagnosis of cancer within 10 years after the blood test. The magnitude of the association varied by cancer type and time elapsed since the blood test. The authors conclude that these findings suggest that a high platelet count is associated with increased cancer risk.