Prognostic and clinicopathological significance of pretreatment mean platelet volume in cancer: a meta-analysis

OBJECTIVE: Our study aimed to evaluate the prognostic and clinicopathological significance of pretreatment mean platelet volume (MPV) on cancer by using meta-analysis of published studies. DESIGN: Meta-analysis. DATA SOURCES: Relevant studies available before 22 December 2019 were identified by searching MEDLINE, EMBASE. ELIGIBILITY CRITERIA: All published studies that assessed the prognostic and clinicopathological significance of pretreatment MPV on cancer were included. DATA EXTRACTION AND SYNTHESIS: Studies were identified and extracted by two reviewers independently. The HR/OR and its 95% CIs of survival outcomes and clinicopathological parameters were calculated. RESULTS: A total of 38 eligible studies (41 subsets) with 9894 patients with cancer were included in the final meta-analysis. MPV level was not significantly associated with both overall survival (HR 0.98, 95% CI 0.84 to 1.14) and disease-free survival (HR 1.22, 95% CI 0.86 to 1.73) of patients with cancer. Neither advanced nor mixed-stage tumour patients showed significant association between MPV and overall survival (HR 1.36, 95% CI 0.96 to 1.94, HR 0.90, 95% CI 0.74 to 1.09). However, high MPV had the strongest relationship with poor overall survival (HR 2.01; 95% CI 1.08 to 3.41) in gastric cancer, followed by pancreatic cancer (HR 1.54; 95% CI 1.31 to 1.82). Whereas in the subgroup using receiver operating characteristic curve method to define cut-off values, low MPV was significantly related to poor overall survival (HR 0.78, 95% CI 0.64 to 0.95). In addition, MPV had no significant association with age (OR 0.96, 95% CI 0.90 to 1.02), sex (OR 1.04, 95% CI 1.00 to 1.09), depth of cancer invasion (OR 0.90, 95% CI 0.77 to 1.04) and tumour stage (OR 0.91, 95% CI 0.78 to 1.07). CONCLUSIONS: Pretreatment MPV level is of no clearly prognostic significance in cancers and no significant association with clinicopathological parameters of patients with cancers.