The prognostic value of thrombocytosis in patients with primary lung cancer

The prognostic information provided by platelet counts was studied in 1115 patients with primary lung cancer and in 550 control patients with benign lung disorders. Patient records were retrospectively reviewed regarding histological tumour type, TNM stage, thromboembolic episodes and survival. The prevalence of thrombocytosis (platelet count > 400 x 10(9)/l) in patients with lung cancer was 32.1% vs. 6.4% in controls (p < 0.0001). Platelet counts increased with TNM stage (p < 0.0001). Patients with thrombocytosis had a shorter survival than patients with normal platelet count (p < 0.0001). Thrombocytosis was a predictor of short survival also when adjusted for tumour type, sex, age, and TNM stage (p < 0.001). The platelet count and the frequency of thrombocytosis declined after tumour resection (p < 0.0001). Thrombocytosis was not associated with thromboembolism. In conclusion, thrombocytosis is a clinically significant prognostic indicator regarding survival in patients with primary lung cancer.