Prognostic Significance of Pretreatment Mean Platelet Volume in Patients with Recurrent or De Novo Metastatic Breast Cancer: A Single-Center Retrospective Study.

Abstract

Background: Breast cancer is the most prevalent malignancy among womificant advances in systemic therapies, metastatic breast cancer remains largely incurable, highlighting the need for reliable prognostic biomarkers. Mean platelet volume (MPV), a routinely measured hematological parameter reflecting platelet size, has been linked to platelet activation, systemic inflammation, and tumor progression. However, the prognostic significance of MPV in recurrent or de novo metastatic breast cancer is unclear. This study evaluated the association between pretreatment MPV and overall survival in this patient population.

Methods: A retrospective analysis was conducted on 200 women with recurrent or de novo metastatic breast cancer. Clinical, pathological, and hematological data were collected from medical records. Pretreatment MPV was measured prior to initiation of systemic therapy. MPV was assessed using both the institutional laboratory upper reference limit of 10.5 fL and an exploratory receiver operating characteristic-derived cutoff of 9.55 fL. Overall survival was defined as the interval from diagnosis of recurrent or de novo metastatic disease to death from any cause or last follow-up. Survival outcomes were compared according to MPV status.

Results: Pretreatment MPV was not significantly associated with overall survival in patients with recurrent or de novo metastatic breast cancer. Using the institutional cutoff of 10.5 fL, median overall survival was 48 months for patients with MPV <10.5 fL (95% CI: 38.161-57.839) and 108 months for those with MPV ≥10.5 fL (95% CI: 26.214-189.800), with no statistically significant difference between groups (p = 0.693). No significant differences were observed between MPV groups regarding age, menopausal status, tumor biomarkers, metastatic characteristics, or recurrence timing. In multivariable analysis, central nervous system metastasis was independently associated with increased mortality (HR 2.22, 95% CI: 1.224-4.027; p = 0.009), whereas MPV status was not independently associated with overall survival (HR 0.81, 95% CI: 0.379-1.750; p = 0.601).

Conclusion: Pretreatment MPV was not identified as an independent prognostic factor for overall survival in patients with recurrent or de novo metastatic breast cancer. Although MPV is an easily accessible hematological parameter, these findings indicate that MPV alone is unlikely to serve as a reliable prognostic biomarker in this clinical context. Further studies with larger cohorts, standardized MPV measurement methods, and adjustment for potential confounding factors are warranted.