Metastatic lymph nodes outside the extended lymphadenectomy template correlate with advanced staging but not grading in prostate cancer patients undergoing radical prostatectomy.

[PURPOSE] This study aimed to evaluate the impact of metastatic lymph nodes (LNs) outside the extended pelvic lymph node dissection (ePLND) template on oncological outcomes, staging, grading, and concomitant parameters in prostate cancer (PCa) patients undergoing radical prostatectomy (RP).

[METHODS] Data from 860 patients with histologically confirmed, non-metastatic PCa who underwent RP between 2012 and 2022 were retrospectively analyzed. All specimens underwent detailed histopathological examination. Preoperative and postoperative clinicopathological data were collected and analyzed. Subgroup associations were evaluated using the Mann-Whitney U test and the Kruskal-Wallis test. Kendall's tau-b coefficient was employed to evaluate the association between two variables. All tests were performed using a two-tailed approach, with a p value of less than 0.05 considered statistically significant for differences between groups. Kaplan-Meier and Cox regression analyses assessed biochemical recurrence (BCR)-free survival based on lymph node invasion (LNI) (pN0 vs. pN1) and the presence of metastatic LNs outside the ePLND template.

[RESULTS] Of the 860 patients, 613 underwent modified-ePLND. Among them, 122 (19.9%) were pN1, with 22 patients (18%) having metastatic LNs located outside the classical ePLND template. Patients with LNs beyond the ePLND template exhibited higher clinical T stages (p = 0.016) and a greater percentage of positive biopsy cores (p = 0.008). However, no correlation was observed with Gleason Grading Group (p = 0.491). Kaplan-Meier analysis showed that pN1 patients had higher BCR rates compared to pN0 patients, but this difference did not reach statistical significance (p = 0.174). Similarly, patients with metastatic LNs outside the ePLND template demonstrated a trend toward increased BCR risk, though this was not statistically significant (p = 0.140).

[CONCLUSION] Metastatic LNs beyond the ePLND template correlate with more advanced tumor staging in PCa. However, they show no association with tumor grading. Their influence on BCR remains inconclusive, likely due to the small number of patients included in the BCR-associated analyses. Extended lymphadenectomy may enhance staging accuracy but must be weighed against the potential for increased surgical morbidity.