[Landscape and metastases of the lymph nodes in prostatic anterior fat pad at radical prostatectomy].

Objectives: To examine the landscape and metastases of the lymph nodes in prostatic anterior fat pad (PAFP) at radical prostatectomy (RP), and to describe the clinical characteristic of the patients with lymph node metastases in PAFP. Methods: The clinical and pathological data of 287 prostate cancer patients underwent RP from December 2019 to August 2021 in Department of Urology, Sun Yat-sen University Cancer Center were collected and analyzed retrospectively. All patients were male, aging (66±7) years (range: 42 to 83 years). The preoperative prostate-specific antigen (PSA) (M(IQR)) were 16.00(29.64) μg/L (range: 0.01 to 99.90 μg/L). There were 244 patients with localized or locally advanced prostate cancer and 43 patients with metastatic prostate cancer. All PAFP were dissected at RP routinely and were sent for pathologic analysis respectively. The PAFP was dissected from the prostate apex caudally toward the bladder neck and dissection extended to the joint of the prostate and the endopelvic fascia bilaterally. All the specimen of PAFP were examined and reported by subspecialty pathologists of genitourinary tumors. Statistical analysis was performed by Student t test, Wilcoxon rank-sum test, χ2 test or Fisher exact test. Results: There were 8.0% (23/287) patients with lymph nodes in PAFP, 3.8% (11/287) patients with PAFP lymph node metastases. Pathologically upstaged occurred in 1 patient due to the PAFP lymph node as the solitary metastatic lesion. Patients with lymph node metastases in PAFP presented higher preoperative PSA (M(IQR): 48.2(73.0) μg/L vs. 15.4(26.5) μg/L, Z=3.158, P=0.002), clinical T stage and N stage (Z=2.977, P=0.003; Z=2.780, P=0.005) and preoperative Gleason score (Z=2.205, P=0.027). Conclusions: Routine dissection of PAFP at RP and separately pathological analysis may allow more lymph nodes and lymph node metastases detection. More accurate pathological N stage may be acquired and consequently may improve the survival of patients by offering more appropriate adjuvant or salvage therapy.