Large platelet size is associated with poor outcome in patients with metastatic pancreatic cancer.

Background Platelets are a major cellular component of blood and their interaction with cancer cells is well-established to influence cancer progression and metastases. The physical size of platelets may have a critical impact on the interaction with cancer cells. In this study, we explored the potential prognostic role of platelet size measured by the determination of the mean platetlet volume (MPV) in patients with pancreatic ductal adenocarcinoma (PDAC). Methods Data from 527 patients with PDAC diagnosed and treated between 2004 and 2015 at a single center were evaluated retrospectively. Associations between MPV and baseline covariates were assessed with Wilcoxon's rank-sum tests, χ2-tests, and Fisher's exact tests. Median follow-up was estimated with a reverse Kaplan-Meier estimator according to Schemper and Smith. Analysis of time-to-death was performed with Kaplan-Meier estimators, log-rank tests and uni- and multivariable Cox proportional hazards models. Results The median MPV was 10.5 femto liter (fL) [9.8-11.3], ranged from 5.9 to 17.7 fL. A large platelet volume was associated with high-grade G3/4 tumors (p=0.004) and worse overall survival (OS) in patients with metastatic disease in univariable analysis (hazard ratio [HR] per fL increase in MPV=1.13 [95% CI: 1.04-1.23, p=0.005]). In multivariable analysis of metatatic PDAC patients, the adverse association between large platelets and a higher risk-of-death prevailed (adjusted HR per doubling of MPV=2.00; 95% CI: 1.10-3.62, p=0.02). Conclusions Large platelets represent a negative prognostic factor and add an independent prognostic information to well-established factors in PDAC patients. MPV should be considered for future individual risk assessment in patients with stage IV PDAC.