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Variations in utilization patterns of pelvic lymph node dissection during open and minimally invasive radical prostatectomy exist independent of pathologic grade and stage
Sandip M. Prasad, MD, M. Phil., Michaella M. Prasad, MD, Jim C. Hu, MD, MPH.
Harvard-Longwood Program in Urology, Boston, MA, USA.

BACKGROUND: Pelvic lymph node dissection (PLND) is commonly performed with radical prostatectomy, perhaps due to an absence of consensus guidelines. We examined whether rates of PLND during varied by surgical approach and radical prostatectomy surgeon volume over time.
METHODS: Within the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked data, we identified 1915 patients who underwent MIRP and 6195 patients who underwent ORP between 2003 and 2006. MIRP and RRP surgeon volume was classified into quartiles to examine the effect of surgeon volume on unadjusted rates of PLND usage. Propensity score analysis was performed to adjust for age, race, income, education, pathologic tumor grade and stage, surgeon volume, SEER region, and surgery year to assess the effect of surgical approach on use of PLND.
RESULTS: Overall, 77% of men underwent PLND, although rates varied by surgical approach (40% vs. 87% for MIRP vs. ORP, respectively, p<0.001). While trend persisted throughout the entire study period, PLND usage decreased for both MIRP and RRP, respectively (Figure). In adjusted analysis, high vs. low volume minimally invasive surgeons were more likely to perform PLND compared with low-volume minimally invasive surgeons (OR 8.13, 95% CI 5.18 - 12.75), but no difference in PLND rates by surgeon volume was seen in ORP (Table 1).

Table 1: SURGEON VOLUME BY APPROACH IN QUARTILES
MIRP SURGEON VOLUME1st Quartile (1-16 cases)2nd Quartile (17-42 cases)3rd Quartile (43-160 cases)4 Quartile (161-424 cases)Totalsp-value
Total patients4855054744511915<0.001
Lymph Node Dissection100159201306766
No LND3853462731451149
% LND20.6%31.5%42.4%67.9%40%
ORP SURGEON VOLUME1st Quartile (1-9 cases)2nd Quartile (10-17 cases)3rd Quartile (18-30 cases)4 Quartile (31-94 cases)Totalsp-value
Total patients186916031745169869150.293
Lymph Node Dissection15451405154315005993
No LND324198202198922
% LND82.7%87.7%88.4%88.3%86.7%
All RP
Total patients8830
LND6759
No LND2071
% LND76.6%
Quartiles are categorized as number of cases over the study period

CONCLUSIONS: Men undergoing MIRP vs. ORP are less likely to undergo PLND although the gap seen in earlier studies has narrowed. Surgeon volume continues to be a strong predictor for performance of PLND. Further studies are needed to determine indications and benefits of this procedure for men with prostate cancer and if this difference carries clinical significance.
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