Detailed analysis of patients with metastasis to the prostatic anterior fat pad lymph nodes: a multi-institutional study

Purpose: Lymph nodes in the prostatic anterior fat pad rarely harbor metastatic disease. Therefore, the characteristics of patients with prostatic anterior fat pad lymph node metastasis are not well described in the literature. We identified the perioperative characteristics and assessed the clinical outcomes of patients with prostatic anterior fat pad lymph node metastasis.

Materials and methods: At 8 tertiary care centers a total of 4,261 patients underwent complete removal and pathological analysis of the prostatic anterior fat pad. We describe preoperative and pathological characteristics, and clinical management and outcomes in patients with metastatic disease to the prostatic anterior fat pad.

Results: Metastatic disease to the prostatic anterior fat pad lymph nodes was detected in 40 patients (0.94%), of whom 37 (92.5%) had intermediate or high risk features preoperatively. Most patients with prostatic anterior fat pad metastases underwent concomitant pelvic lymph node dissection, and adjuvant therapy with radiation, androgen ablation and/or chemotherapy. A total of 27 patients (67.5%) with prostatic anterior fat pad metastatic disease were up-staged as a result of prostatic anterior fat pad pathological analysis, of whom 14 (51.8%) remained free of biochemical recurrence with observation and/or definitive adjuvant/salvage therapy.

Conclusions: Most patients with prostatic anterior fat pad metastatic disease had intermediate to high risk features preoperatively. In some patients with such lymph node metastasis removing these lymph nodes resulted in prolonged biochemical recurrence-free survival. Therefore, we recommend that the prostatic anterior fat pad be removed in all patients undergoing radical prostatectomy. However, pathological analysis of the prostatic anterior fat pad may be limited to patients with intermediate to high risk oncological features preoperatively.