Incidence, location, and significance of periprostatic and periseminal vesicle lymph nodes in prostate cancer

Pelvic lymph node metastases in prostate cancer (PCa) carry an ominous prognosis. Periprostatic/periseminal vesicle (PP/PSV) lymph nodes are present in some individuals, but their incidence and involvement by metastases are unknown. A total of 832 of 1233 (67.5%) patients who underwent radical retropubic prostatectomy for clinically localized PCa at the Methodist Hospital from 1983 to 1998 by one surgeon (P.T.S.) had wholemount slides available for review. Of these, 92 (11.1%) had received preoperative therapy (radiation in 48 [5.8%], hormonal in 44 [5.3%]). Slides were examined with the naked eye by placing them on a white illuminated background, and any area suggestive of a lymph node in PP/PSV fat was confirmed microscopically and assessed for the presence of metastases. Thirty-seven of 832 patients (4.4%) had 39 PP/PSV lymph nodes-one bilateral, one with two ipsilateral lymph nodes, and the rest solitary. Sizes ranged from 0.7 to 4.5 mm (mean 1.8 min). Distribution was 2 of 39 (5.1%) apical, 3 of 39 (7.7%) mid, 17 of 39 (43.6%) base, and 17 of 39 (43.6%) seminal vesicle. Five patients (0.6%) had metastatic PCa to the PP/PSV lymph nodes. All five patients were of advanced pathologic T stage [one pT3a (extraprostatic extension) and four pT3b (seminal vesicle invasion)]. Only two of those five (40%) had metastases (all ipsilateral) to pelvic lymph nodes. In three of five (60%) the metastases were isolated to the PP/PSV lymph nodes. Metastases were to the lymph nodes in the periseminal vesicle fat in four of five (80%) of the cases and in the fat surrounding the base of the prostate in one of five (20%). Four of five (80%) patients recurred. Histologic grade (Gleason score), tumor volume, and failure (recurrence) rates were significantly different between the five patients with metastases and the 32 patients without metastases to the PP/PSV lymph nodes (p <0.0001, p <0.0001, and p = 0.005, respectively). However, there was no evidence that an individual patient's probability of having a PP/PSV lymph node increased with resection of the neurovascular bundle (p = 0.7698). PP/PSV lymph nodes are uncommon, but based upon these limited data, it appears that patients with metastases limited to PP/PSV lymph nodes have a poor prognosis (similar to pelvic lymph node metastases) and should be included in the American Joint Committee on Cancer (AJCC) Staging Manual to indicate "N1" if positive for metastases.