Preoperative platelet-to-lymphocyte ratio as a predictor of inguinal lymph node metastasis in penile cancer

Penile cancer (PC) is a rare malignancy with poor prognosis. To date, reliable preoperative biomarkers for lymph node status and prognosis are still lacking. This study aims to explore the potential role of preoperative platelet-to-lymphocyte ratio (PLR) as a predictor of inguinal lymph node invasion in PC patients. Retrospective analysis was conducted on anamnestic, clinical, and laboratory data of PC patients who underwent surgical treatment between January 2016 and October 2023. Inguinal lymphadenectomy was performed as per EAU guidelines. PLR, calculated as the ratio between platelet-to-lymphocyte values obtained from preoperative blood analyses, was assessed within 30 days before surgery. Patients were categorized into pN- (no lymph node metastasis) and pN+ (lymph node metastasis confirmed pathologically). Statistical analyses included Kruskal-Wallis and Mann-Whitney U tests, univariate logistic regression, and ROC curve analysis with Youden index, assuming p<0.05 as statistically significant. Overall, 60 PC patients were retrospectively involved in the study. A total of 36 (60%) patients reported ILN metastases, confirmed by inguinal lymphadenectomy (pN+), while no ILN metastases (pN-) were reported in 24 (40%) patients. The AUC for predicting ILN metastasis by preoperative PLR was 0.71 (p=0.014). According to the ROC curve analysis and the Youden Index, a cut-off for PLR was set at 122.4. On Univariable logistic regression analysis, the presence of T stage ≥ 2 (OR = 3.21; 95% CI: 1.43-7.47, p=0.011), lymphovascular invasion (OR = 3.78; 95% CI: 1.56-5.90, p=0.003), clinical node-positive disease (OR = 19.86; 95% CI: 5.91-41.03, p<0.001) and PLR ratio > 122.4 (OR = 7.22; 95% CI: 1.41-22.71, p=0.0148) were independent predictors of pN+ disease. The current study confirms the relationship between cancer and inflammation. When elevated preoperatively, PLR may be associated with inguinal lymph node invasion in PC patients.