DOI: https://doi.org/10.36347/sasjm.2026.v12i10.017

Pages: 1121-1124

Thrombocytosis is a common abnormality encountered in primary care and is frequently attributed to reactive causes such as inflammation, infection or iron deficiency. Although it is often detected incidentally on routine blood tests, persistent or unexplained thrombocytosis warrants careful assessment. Primary-care studies have demonstrated an association between thrombocytosis and a subsequent cancer diagnosis, with notable associations reported for lung, endometrial, gastric and colorectal cancers, among others [1,2]. However, thrombocytosis is neither a diagnostic test for cancer nor a reliable means of excluding it. Instead, it should prompt clinicians to consider the whole clinical picture and arrange appropriate investigation when a reactive explanation is not evident. This is particularly important in patients with non-specific symptoms or no immediately suggestive examination findings. This article reviews the differential diagnosis of thrombocytosis, its association with cancer, a practical approach to investigation and the importance of safety-netting.