BERKELEY, CA (UroToday.com) - At radical prostatectomy, pelvic lymph node dissection (PLND) represents the most accurate lymph node (LN) staging procedure.
We evaluated the rate of PLND use and its LN count over the last two decades. Moreover, we tested the relationship between LN count and the rate of pN1 stage.
We examined 130,080 patients treated with radical prostatectomy, between 1988 and 2006, within 17 Surveillance, Epidemiology, and End Results registries. LN count was modeled as a categorical variable using quartiles: 1-3, 4-6, 7-10 and 11-40 nodes. Chi-square trend test examined temporal trends for proportions. Univariable and multivariable logistic regression analyses (MVA) tested the relationship between predictors and two endpoints:
- pNx stage and,
- pN1 stage.
The rate of pNx stage was 25.9%, and it increased from 20.8% in 1988-1993 to 30.1% in 2000-2006 (p<0.001). In MVA, most contemporary year of surgery was an independent predictor of a higher pNx rate (p<0.001). In 96,365 patients subjected to PLND, the percentage of patients in the 1st and 2nd LN count quartiles increased from respectively 13.5 and 19.2% in 1988 to 40.3 and 26.6% in 2006 (p<0.001). Conversely, the percentage of patients in the 3rd and 4th quartiles decreased from respectively 19.7 and 47.6% in 1988 to 17.0 and 16.1% in 2006 (p<0.001). The rate of pN1 stage was 3.4%, and it decreased from 6.6% in 1988-1993 to 2.7% in 2000-2006 (p<0.001). The rate of pN1 stage was related to LN count. Specifically, 1.4% of patients in the 1st LN count quartile had pN1 stage vs. 2.8, 3.8 and 6.3% of patients in respectively 2nd, 3rd, and 4th LN count quartiles (p<0.001). In MVA predicting the rate of pN1 stage, the latter increased by 1.9, 2.5, and 3.9-fold, when LN counts consisted of the 2nd, 3rd, and 4th quartiles compared to the 1st quartile (all p <0.001).
Our study showed a clear trend with fewer PLNDs performed over time at radical prostatectomy. Additionally when PLND is performed, LN count is frequently insufficient, which undermines the ability of PLND to detect pN1 stage. As a direct result, fewer patients are diagnosed with LN metastases. The impact of this phenomenon on cancer control outcomes is still to be verified.
Firas Abdollah, MD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.