Systemic Inflammatory Response in Predicting Prostate Cancer: The Diagnostic Value of Neutrophil-To-Lymphocyte Ratio

Over the past decades, the study of the microenvironment of cancer has supported the hypothesis between inflammation and cancer. Previous studies have demonstrated a promising value of platelet-to-lymphocyte (PLR) and neutrophil-to-lymphocyte ratio (NLR) as a systemic inflammatory response in prostate cancer.

To evaluate their pre-biopsy values of PLR and NLR in predicting prostate cancer.

This is a diagnostic study with retrospective design. We included all benign prostatic hyperplasia (BPH) and prostate cancer (PCa) patients who underwent prostate biopsy in Adam Malik Hospital between August 2011 and August 2015. We used PSA value above 4 ng/dL as the threshold for the biopsy candidates. The relationship between pre-biopsy variables affecting the percentage of prostate cancer risk was evaluated, including age, prostate-specific antigen (PSA) level, and estimated prostate volume (EPV). The PLR and NLR were calculated from the ratio of related platelets or absolute neutrophil counts with their absolute lymphocyte counts. The values then analysed to evaluate their associations with the diagnosis of BPH and PCa.

Out of 298 patients included in this study, we defined two groups consist of 126 (42.3%) BPH and 172 PCa (57.7%) patients. Mean age for both groups are 66.36 ± 7.53 and 67.99 ± 7.48 years old (p = 0.64), respectively. There are statistically significant differences noted from both BPH and PCa groups in terms of PSA (19.28 ± 27.11 ng/dL vs 40.19 ± 49.39 ng/dL), EPV (49.39 ± 23.51 cc vs 58.10 ± 30.54 cc), PLR (160.27 ± 98.96 vs 169.55 ± 78.07), and NLR (3.57 ± 3.23 vs 4.22 ± 2.59) features of both BPH and PCa groups respectively (p < 0.05). A Receiver Operating Characteristics (ROC) analysis was performed for PLR and NLR in analysing their value in predicting prostate cancer. The Area Under the Curve (AUC) of PLR is 57.9% with a sensitivity of 56.4% and specificity of 55.6% in the cut-off point of 143 (p = 0.02). The NLR cut-off point of 3.08 gives 62.8% AUC with 64.5% sensitivity and 63.5% specificity. These AUCs were comparable with the AUC of PSA alone (68.5%). We performed logistic regression between PSA, PLR, and NLR with result in the exclusion of PLR if calculated conjunctively. Therefore, NLR has a promising performance in predicting PCa in patients with PSA above 4 ng/dL (OR = 3.2; 95%CI: 1.96-5.11). We found as many as 80 (63.5%) patients with benign biopsy results with negative NLR value in this study.

NLR has promising value in predicting prostate cancer. A further prospective study in validating its diagnostic value was needed.