PROGNOSTIC-SIGNIFICANCE OF THROMBOCYTOSIS IN PATIENTS WITH PRIMARY LUNG-CANCER

In patients with malignancies, thrombocytosis has previously been rela ted to disease stage, histological type, and survival, In the present study, the prevalence of thrombocytosis and the prognostic information provided by platelet counts were analysed in a large cohort of patien ts with primary lung cancer. At the time of diagnosis, pretreatment pl atelet counts were retrospectively recorded in 1,115 consecutive patie nts with histologically proven primary lung cancer, All patients were reviewed regarding histological type, tumour, node, metastasis (TNM) c lassification stage and survival, The prevalence of thrombocytosis in patients with lung cancer was compared with that in a series of 550 co nsecutive out-patients with benign lung disorders, In 269 surgically r esected patients, postoperative platelet counts were recorded 1-3 mont hs after resection of the tumour, In the follow-up period, thromboembo lic episodes diagnosed either clinically or at autopsy were recorded. The overall prevalence of thrombocytosis (>400 x 10(9) platelets . L(- 1)) in the patients with lung cancer was 32%, The frequency of thrombo cytosis was significantly higher compared with the control subjects (3 2 vs 6%; p<0.0001). Platelet counts differed significantly among subgr oups defined by the TNM classification, with the proportion of patient s with >400x10(9) platelets . L(-1) greatest in the more advanced TNM stages (stage I and II 23% vs stage III and IV 37%; p<0.0001), Patient s with thrombocytosis had a significantly poorer survival than patient s with normal platelet counts (p<0.0001), In a multivariate survival a nalysis (Cox model), thrombocytosis continued to correlate strongly wi th poor survival even when adjusted for histological type, sex, age, a nd TNM stage (p<0.001), In surgically resected patients, the frequency of preoperative and postoperative thrombocytosis differed significant ly (23.0 vs 8.9%; p<0.0001). Survival rate was significantly reduced i n patients with preoperative thrombocytosis (p=0.005). Thrombocytosis was not associated with an increased incidence of thromboembolism. In conclusion, thrombocytosis is an independent prognostic factor of surv ival in patients with primary lung cancer, We suggest that platelet co unts should be included in future multivariate analyses of survival in patients with lung cancer.