Objective: Platelets have been implicated in cancer metastasis and prognosis. No population-based study has been reported as to whether preoperative platelet count directly predicts metastatic recurrence of colorectal cancer (CRC) patients.
Design: Using a well-characterized cohort of 1,513 surgically resected CRC patients, we assessed the predictive roles of preoperative platelet count in overall survival, overall recurrence, as well as locoregional and distant metastatic recurrences.
Results: Patients with clinically high platelet count (≥400 × 10(9)/L) measured within 1 month before surgery had a significantly unfavorable survival (hazard ratio [HR] = 1.66, 95 % confidence interval [CI] 1.34-2.05, P = 2.6 × 10(-6), P(log rank) = 1.1 × 10(-11)) and recurrence (HR = 1.90, 1.24-2.93, P = 0.003, P(log rank) = 0.003). The association of platelet count with recurrence was evident only in patients with metastatic (HR = 2.81, 1.67-4.74, P = 1.1 × 10(-4), P(log rank) = 2.6 × 10(-6)) but not locoregional recurrence (HR = 0.59, 95 % CI 0.21-1.68, P = 0.325, P(log rank) = 0.152). The findings were internally validated through bootstrap resampling (P < 0.01 at 98.6 % of resampling). Consistently, platelet count was significantly higher in deceased than living patients (P < 0.0001) and in patients with metastatic recurrence than locoregional (P = 0.004) or nonrecurrent patients (P < 0.0001). Time-dependent modeling indicated that the increased risks for death and metastasis associated with elevated preoperative platelet counts persisted up to 5 years after surgery.
Conclusion: Our data demonstrated that clinically high level of preoperative platelets was an independent predictor of CRC survival and metastasis. As an important component of the routinely tested complete blood count panel, platelet count may be a cost-effective and noninvasive marker for CRC prognosis and a potential intervention target to prevent metastatic recurrence.