[1032] Correlation between Laterality of Pelvic Lymph Node Metastases and Tumor Laterality in Biopsy and Prostatectomy Specimens from Patients Undergoing Extended Pelvic Lymph Node Dissection (ePLND)

Patricia Troncoso, Surena Matin, Kara N Babaian, Ina N Prokhorova, John W Davis. The University of Texas MD Anderson Cancer Center, Houston, TX

Background: The optimal extent of lymph node dissection at the time of radical prostatectomy has been the subject of ongoing debate and study. Although older nomograms have predicted which patients may not require a lymph node dissection, those guidelines were largely derived from dissections limited to the obturator fossa. The use of the extended template (i.e., obturator + external iliac + hypogastric nodes regions) generally doubles the number of lymph nodes retrieved and thus increases the likelihood of N1 disease detection. Because the operative time required for the extended template is longer, we sought to re-explore whether the extended dissection is required bilaterally or only unilaterally in the case of predominantly unilateral disease.
Design: Patients with N1 disease who underwent robot-assisted ePLND from November 2007 through August 2011 were included in our study. Preoperatively treated patients were excluded. The location, Gleason score (GS), and grades of the individual tumor foci in the mapped radical prostatectomy specimens (RPS) and tumor laterality in the biopsy specimens were related to the side of lymph node metastases in the ePLND.
Results: The median age of the 52 patients at prostatectomy was 62 years (range, 47–76). The median PSA was 7.85 ng/ml (range, 1.10–119). Most patients underwent an extended biopsy with a median of 12 cores. The biopsy GS was ≤ 7 in 32 patients and ≥ 8 in 20. The clinical stage was T1c in 22 patients, T2 in 29, and T3 in 1. The GS was 7 in 24 RPS and ≥ 8 in 28 RPS. The pathologic stage was pT2 in 10 patients, pT3a in 12, and pT3b in 30. The median numbers of lymph nodes obtained and of positive nodes, respectively, were 20.5 and 1. The tumor focus with the highest GS was exclusively unilateral in 13 patients, predominantly unilateral in 19, and bilateral in 20. Metastases contralateral to the side of the focus with the highest GS were present in 3 of 13 (23%) patients with exclusively unilateral disease and 7 of 19 (37%) with predominantly unilateral disease. Overall, 6 of 23 (26%) patients with unilateral disease in the biopsy specimen had contralateral metastases, including 3 of 14 (21%) patients with intermediate-risk and 3 of 9 (33%) with high-risk prostate cancer.
Conclusions: The occurrence of pelvic lymph node metastases contralateral to the focus of the highest GS supports the concept that, ePLND, when clinically indicated, should be performed bilaterally.
Category: Genitourinary (including renal tumors)

Tuesday, March 20, 2012 1:00 PM

Poster Session IV # 117, Tuesday Afternoon


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