Platelet to lymphocyte ratio as an independent prognostic indicator for prostate cancer patients receiving androgen deprivation therapy

Background: Platelet to Lymphocyte ratio (PLR) is thought to be associated with a worse outcome in multiple types of cancer. However, the prognostic significance of PLR has not been investigated in the prostate cancer (PCa) patients receiving hormonal therapy. The objective of this study was to determine the prognostic value of PLR in PCa patients treated with androgen deprivation therapy (ADT). Methods: Two-hundred-ninety prostate cancer patients who had undergone ADT as first-line therapy were retrospectively analyzed. The blood cell counts were performed at the time of diagnosis. PLR was calculated as the ratio of platelet count to lymphocyte count. Patients were categorized in two groups using a cut-off point of 117.58 as calculated by the receiver-operating curve analysis. Correlations between PLR and clinical characteristics were analyzed. Meanwhile, univariate and multivariate cox regression analyses were performed to determine the associations of PLR with progression-free survival (PFS), cancer-specific survival (CSS) and overall survival (OS). Prognostic accuracy was evaluated with the Harrell concordance index. Results: The differences of age, serum prostate-specific antigen (PSA) level, Gleason score, risk stratification and incidence of metastasis between low PLR group (< 117.58) and high PLR group (>= 117.58) were not statistically significant (p > 0.05). Multivariate analyses identified PLR as an independent prognostic factor for PFS (hazard ratio (HR) = 1.581, p = 0.013), CSS (HR = 1.768, p = 0.037) and OS (HR = 1.650, p = 0.044). The addition of PLR to the final model improved predictive accuracy (c-index: 0.747, 0.801 and 0.768) for PFS, CSS and OS compared with the clinicopathological base model (c-index: 0.730, 0.778 and 0.746), which included Gleason score and incidence of metastasis. Conclusions: PLR might play a significant role in the prognosis of PCa patients treated with ADT. Thus, we recommend adding PLR to traditional prognostic model to improve the predictive accuracy.