Background: The elevation of the platelet-to-lymphocyte ratio (PLR), an easily applicable blood test based on platelet and lymphocyte counts has been associated with poor prognosis in patients with different types of cancer. The present study was aimed to investigate the prognostic significance of the preoperative PLR in a large cohort of breast cancer patients.
Methods: Data from 793 consecutive non-metastatic breast cancer patients, treated between 1999 and 2004, were evaluated retrospectively. The optimal cutoff values for the PLR were calculated using receiver operating curve analysis. Cancer-specific survival (CSS), overall survival (OS) as well as distant metastasis-free survival (DMFS) were assessed using the Kaplan-Meier method. To evaluate the independent prognostic significance of PLR, multivariable Cox regression models were applied for all three different end points.
Results: Univariable analysis revealed a significant association between the elevated preoperative PLR and CSS (hazard ratio (HR): 2.75, 95% confidence interval (CI): 1.57-4.83, P<0.001) that remained statistically significant in multivariable analysis (HR: 2.03, 95% CI: 1.03-4.02, P=0.042). An increased PLR was also significantly associated with decreased OS in univariable (HR: 2.45, 95% CI: 1.43-4.20, P=0.001) and in multivariable analysis (HR: 1.92, 95% CI: 1.01-3.67, P=0.047). Furthermore, univariable analysis showed a significant impact of increased PLR on DMFS (HR: 2.02, 95% CI: 1.18-3.44, P=0.010). Subgroup analysis revealed significant associations of the elevated PLR on the primary end point CSS for all breast cancer subtypes. This association retained its significance in multivariable analysis in patients with luminal B tumours (HR: 2.538, 95% CI: 1.043-6.177, P=0.040).
Conclusions: In this study, we identified the preoperative PLR as an independent prognostic marker for survival in breast cancer patients. Independent validation of our findings is needed.