Preoperative platelet count associates with survival and distant metastasis in surgically resected colorectal cancer patients

Abstract

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.

Conflict of interest statement

Conflict of Interest: The authors declare that they have no conflict of interest.

Figures

Fig. 1

CONSORT diagram of study population. CRC colorectal cancer, LRR locoregional recurrence, DMR distant metastatic recurrence, TJUH Thomas Jefferson University Hospital

Fig. 2

Kaplan–Meier curves of the analyses between platelet count and four clinical endpoints including overall survival, overall recurrence, LRR, and DMR, evaluated by the average (a to d), maximum (e to h), or minimum (i to l) values of platelet count levels measured within 1 month before surgery. LRR locoregional recurrence, DMR distant metastatic recurrence

Fig. 3

The distributions of the maximum value of platelet count by CRC clinical outcomes. a Comparisons of platelet count values between deceased and alive patients (left panel) and between DMR, LRR, and NR patients (right panel). b Comparisons of average value of platelet count measured in different time periods before surgery between deceased and alive patients (left panel) and between DMR, LRR, and NR patients (right panel). The platelet count values were presented as average ± standard error. LRR locoregional recurrence, DMR distant metastatic recurrence, NR no recurrence

Fig. 4

Time-dependent effect of platelet count on CRC clinical outcomes. Flexible parametric modeling was used to predict the effect by platelet count on the 5-year a overall survival and b distant metastatic recurrence (DMR) after surgery. The analyses were adjusted for age, gender, ethnicity, smoking status, drinking status, primary tumor site, tumor stage, tumor grade, chemotherapy, and radiation therapy. Solid lines, hazards ratios; shaded areas, 95 % confidence intervals