[789] Periprostatic Lymph Node Metastasis in Prostate Cancer and Its Clinical Significance.

Fang-Ming Deng, Savvas E Mendrinos, Kasturi Das, Jonathan Melamed. New York University Medical Center, NY

Background: Lymph node (LN) stage in prostate cancer (PCa) is traditionaly based on evaluation of pelvic lymph nodes. The potential of the periprostatic lymph node incidentaly discovered in the radical prostatectomy specimen as a staging indicator has not been fully explored, particularly with use of methods for enhanced detection of micrometastasis.
Design: Radical prostatectomy cases accrued between 1997 and 2007 at our institution were retrieved based on the notation of periprostatic LN(s) in the pathology report. H& E slides were reviewed to characterize the LNs (number, size and location) and the histopathologic features of the metastasis in respect to the primary tumor. LNs were studied for micrometastasis using cytokeratin (AE1/AE3) immunostaining. The status of the periprostatic LN was correlated with tumor size, pre-operative serum PSA, histological grade, stage, surgical margin status and PSA recurrence.
Results: Twenty-one (0.8%) of 2663 radical prostatectomy specimens had periprostatic LN(s) with one case containing two periprostatic LNs (total number of LNs = 22). Lymph node size ranged from 0.8 to 4.7 mm (mean 1.9 mm). Most of the periprostatic LNs were located close to the posterior base. Seven (32%) of 22 LNs (6 cases) were involved by metastatic PCa including 5 detected on routine H & E slides and additional 2 detected only by immunohistochemistry. Cases with periprostatic LNs had a significantly higher metastatic rate (29%; 6 of 21) as compared to those with pelvic LNs sampled at radical prostectatomy in our institution (1.9%). The metastatic foci ranged from <0.1 mm to 4.2 mm. The concurrently submitted pelvic LNs in all 6 cases were negative for metastasis. The tumor characteristics of cases with metastatic periprostatic LNs (n=6) when compared to cases with negative periprostatic LNs (n=15) included higher tumor volume, Gleason score and pT stage. Cases with metastatic periprostatic LN showed a greater propensity for PSA recurrence [80%; 4 of 5] as compared to cases with negative periprostatic LN [27%; 4 of 15].
Conclusions: Periprostatic LNs are small lymph nodes infrequently identified in radical prostatectomy specimens, where they are usually located in the region of the posterior base. They are more commonly involved by metastatic PCa than pelvic LNs sampled at time of radical prostatectomy and predict for PSA recurrence. Despite their infrequent identification, periprostatic LNs if detected in the radical prostatectomy specimen should be evaluated with greater scrutiny (step sections and/ or immunohistochemical studies) to fulfil their prognostic potential.
Category: Genitourinary (including renal tumors)

Monday, February 28, 2011 1:00 PM

Poster Session II # 128, Monday Afternoon

 

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