Aims- To investigate the prognostic value of thrombocytosis in patients with colorectalcancer. Method - Charts of 243 patients with colorectal cancer that had undergonesurgical treatment were retrospectively reviewed. Data on TNM staging, tumor recurrenceand cancer death were compared with the occurrence of thombocytosis before surgery.The control group was formed by fifty patients submitted to herniorrhaphy. Patientswere divided into two groups on the basis of mean platelet count of control group:group 1, patients with platelet count below that mean and group 2, patients withplatelet count above that level. Results - The mean platelet count was 317000/ìlamong cancer patients and 267000/ìl in the control group patients. Prevalenceof thrombocytosis in patients with colorectal cancer was 32,1%. The cancer deathrate was 56,7% in patients with thrombocytosis and 32% in patients with normalplatelet count (p=0,001). When the platelet count mean of control group was used,the difference was significantly greater (p=0004). Tumor recurrence occurred in40% of group 2 patients and in 17,9% of group 1 patients (p=0,003). RegardingT staging, on group 1, 14,1% of patients were T1 and 8,4% were T4. On group 2,2,2% were T1 and 19,5% were T4 (p=0,0005). Distant metastasis were found in 9,4%patients of group 1 and 21,8% of group 2 (p=0,02). Considering TNM staging, group1 had 24,6% of patients in stage 1 and 11% in stage 4. On group 2, 9,6% belongedto stage 1 and 22,8% to stage 4 (p=0,02). Conclusion - Preoperative platelet countseems to be a helpful indicator of patients with poor prognosis.
