[Lymph node metastasis in the prostatic anterior fat pad and prognosis after robot-assisted radical prostatectomy].

Objective: To investigate lymph node metastasis (LNM) in the prostatic anterior fat pad (PAFP) of PCa patients after robot-assisted radical prostatectomy (RARP), and analyze the clinicopathological features and prognosis of LNM in the PAFP.

Methods: We retrospectively analyzed the clinicopathological data on 1 003 cases of PCa treated by RARP in the Department of Urology of PLA General Hospital from January 2017 to December 2022. All the patients underwent routine removal of the PAFP during RARP and pathological examination, with the results of all the specimens examined and reported by pathologists. Based on the presence and locations of LNM, we grouped the patients for statistical analysis, compared the clinicopathological features between different groups using the Student's t, Mann-Whitney U and Chi-square tests, and conducted survival analyses using the Kaplan-Meier and Log-rank methods and survival curves generated by Rstudio.

Results: Lymph nodes were detected in 77 (7.7%) of the 1 003 PAFP samples, and LNM in 11 (14.3%) of the 77 cases, with a positive rate of 1.1% (11/1 003). Of the 11 positive cases, 9 were found in the upgraded pathological N stage, and the other 2 complicated by pelvic LNM. The patients with postoperative pathological stage≥T3 constituted a significantly higher proportion in the PAFP LNM than in the non-PAFP LNM group (81.8% ［9/11］ vs 36.2% ［359/992］, P = 0.005), and so did the cases with Gleason score ≥8 (87.5% ［7/8］ vs 35.5% ［279/786］, P = 0.009). No statistically significant differences were observed in the clinicopathological features and biochemical recurrence-free survival between the patients with PAFP LNM only and those with pelvic LNM only.

Conclusion: The PAFP is a potential route to LNM, and patients with LNM in the PAFP are characterized by poor pathological features. There is no statistically significant difference in biochemical recurrence-free survival between the patients with PAFP LNM only and those with pelvic LNM only. Routine removal of the PAFP and independent pathological examination of the specimen during RARP is of great clinical significance.