Thrombocytosis as a predictor of distant recurrence in patients with rectal cancer

Thrombocytosis is frequently observed in patients with malignancy. We undertook this study to determine the prognostic value of thrombocytosis in patients with rectal cancer.

We performed a retrospective study of patients undergoing low anterior resection for rectal cancer between January 2000 and March 2007. Preoperative platelet count was measured before surgery. Postoperative platelets were determined 1 month after surgery. Two-tailed p values <0.05 were considered statistically significant.

One hundred sixty three patients with rectal cancer were included in the study. Preoperative platelet count >350,000 was found in 8% of patients. Postoperative platelet count >350,000 was found in 6% of patients. Distant metastases were found in 17 patients (10.4%). Significant variables in the multivariate analyses were preoperative platelets >350,000 (p = 0.001), postoperative platelets >350,000 (p = 0.002), carcinoembryonic antigen >13 ng/dL (p = 0.003). Patients with preoperative platelet count <350,000 showed a 5-year survival rate of 81%, whereas patients with platelet count >350,000 had a 25-month survival [95% confidence interval (CI): 20-26]; p <0.001. Patients with postoperative platelets <350,000 showed a 5-year survival rate of 80%, whereas patients with platelets >350,000 showed a 3-year survival rate of 37.5% (p <0.05).

Pre- or postoperative platelet count >350,000 is associated with poor survival in patients with rectal cancer. The measurement of platelets is a clinical marker useful to define the prognosis for patients with rectal cancer.