Elsevier

European Urology

Volume 58, Issue 6, December 2010, Pages 882-892
European Urology

Prostate Cancer
Decreasing Rate and Extent of Lymph Node Staging in Patients Undergoing Radical Prostatectomy May Undermine the Rate of Diagnosis of Lymph Node Metastases in Prostate Cancer

https://doi.org/10.1016/j.eururo.2010.09.029Get rights and content

Abstract

Background

At radical prostatectomy (RP), pelvic lymph node dissection (PLND) represents the most accurate staging procedure for the presence of lymph node (LN) metastases.

Objective

We evaluated the rate of PLND use and its lymph node count (LNC) over the last two decades. We also tested the relationship between LNC and the rate of pN1 stage.

Design, setting, and participants

Between 1988 and 2006, 130 080 RPs were recorded in 17 Surveillance Epidemiology and End Results registries.

Measurements

The statistical significance of temporal trends was evaluated with the chi-square trend test. Separate univariable and multivariable regression analyses tested the relationship between predictors and two end points: (1) lack of LN staging (pNx) and (2) presence of LN metastases (pN1).

Results and limitations

Stage pNx was recorded in 25.9% of patients, and pNx rate was higher in more contemporary years (30.1% in 2000–2006 vs 20.8% in 1988–1993; multivariable p < 0.001). When PLND was performed, an average of 7.4 LNs (median: 6) were removed. The average LNC decreased from 12.0 nodes (median: 12) in 1988 to 6.0 nodes (median: 4) in 2006. Overall pN1 rate was 3.4% and decreased from 10.7% to 3.1% between 1988 and 2006 (p < 0.001). LNC was an independent predictor of pN1 stage (multivariable p < 0.001).

Conclusions

An increasingly larger proportion of prostate cancer patients remain without LN staging at RP. Fewer LNs were removed at PLND over time, resulting in fewer patients diagnosed with pN1 stage at RP. The impact of this phenomenon on cancer control outcomes is still to be verified.

Introduction

Most prostate cancer patients present with clinically localized disease and are treated with radical prostatectomy (RP) [1], [2]. At surgery, pelvic lymph node dissection (PLND) represents the most accurate staging procedure for the presence of lymph node (LN) metastases [3], [4].

Over the past two decades, an ongoing debate has focused on the extent of PLND that should ideally be performed to more accurately assign LN stage [3]. The opinions range from omitting the PLND [5], [6] to performing an extended PLND that encompasses virtually all pelvic LNs [7], [8]. To date, only institutional studies of limited sample size have examined the relationship between the extent of PLND and its ability to detect the presence of LN metastases [7], [8], [9], [10], [11], [12], [13], [14], [15]. Therefore the existing data regarding the indications, rationale, and extent of PLND originate from relatively small studies. Based on the paucity of data, we decided to examine the rate of PLND and the variation in LN count (LNC) at PLND over the past two decades within the Surveillance Epidemiology and End Results (SEER) database. We also examined the relationship between LNC and the likelihood of finding LN metastases.

Section snippets

Patient population

Patients treated with RP for histologically confirmed nonmetastatic adenocarcinoma of the prostate between 1988 and 2006 were identified using the 17 SEER [16] database (International Classification of Disease for Oncology [61.9]; histologic code: 8140). All patients were between 34 and 94 yr of age. Patients with missing stage and/or grade were excluded. We also excluded individuals with undifferentiated disease because this histology may be confounded with small cell histology. These

Results

A total of 130 080 patients treated with RP were evaluated (Table 1). PLND was omitted (pNx) in 25.9% of patients. The rate of pNx was 29% in pT2 patients versus 14.5% and 16.7% in pT3 and pT4 patients, respectively (p < 0.001). Similarly, the rate of pNx was 27.0%, 27.2%, and 22.9% in patients with Gleason scores 2–4, 5–7, and 8–10, respectively (p < 0.001). The rate of pNx increased in the most contemporary year of the surgery category (30.1% in 2000–2006 vs 20.8% in 1988–1993; p < 0.001). The rate

Discussion

The objective of our analysis was threefold. First, we examined the rate of PLND and found that 26% of individuals did not undergo a PLND at RP. The probability of undergoing a PLND decreased over time. In the most contemporary year (2006), 30% of patients were pNx. Moreover, important interregistry differences in pNx stage were recorded: 14–50%. Patients with more favorable stage (pT2) and grade (Gleason score 2–4) were most frequently left without PLND. Nonetheless, 21.1%, 14.5%, 16.7%, and

Conclusions

Our study showed a clear trend with fewer PLNDs performed over time at RP, even in patients with unfavorable preoperative clinical and/or pathologic characteristics. Additionally, when PLND is performed, LNC is frequently insufficient, which undermines the ability of PLND to detect pN1 stage. As a direct result, fewer patients are diagnosed with LN metastases. Our findings cannot be attributed exclusively to stage migration. The impact of this phenomenon on cancer control outcomes still needs

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Both authors contributed equally to the manuscript.

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