Original article
Lymph node yield during radical prostatectomy does not impact rate of biochemical recurrence in patients with seminal vesicle invasion and node-negative disease

https://doi.org/10.1016/j.urolonc.2018.03.004Get rights and content

Highlights

  • Survival effect of lymph node yield in pT3b patients was analyzed.

  • Receipt of lymph node yield does not influence biochemical recurrence.

  • Greater lymph node yield did not influence biochemical recurrence.

  • PSA and Gleason Score are associated with biochemical recurrence

Abstract

Objectives

Seminal vesicle invasion (SVI) is a risk factor for poor oncologic outcome in patients with prostate cancer. Modifications to the pelvic lymph node dissection (PLND) during radical prostatectomy (RP) have been reported to have a therapeutic benefit. The present study is the first to determine if lymph node yield (LNY) is associated with a lower risk of biochemical recurrence (BCR) for men with SVI.

Methods

A total of 220 patients from 2 high-volume institutions who underwent RP without adjuvant treatment between 1990 and 2015 and had prostate cancer with SVI (i.e., pT3b) were identified, and 21 patients did not undergo lymph node dissection. BCR was defined as a postoperative PSA>0.2 ng/mL, or use of salvage androgen deprivation therapy (ADT) or radiation. Multivariable Cox proportional hazards models were used to determine whether LNY was predictive of BCR, controlling for PSA, pathologic Gleason Score, pathologic lymph node status, NCCN risk category, etc. The Kaplan-Meier method was used to determine 3-year freedom from BCR.

Results

Median number of lymph nodes sampled were 7 (IQR: 3–12; range: 0–35) and 90.5% underwent PLND. The estimated 3-year BCR rate was 43.9%. Results from multivariable analysis demonstrated that LNY was not significantly associated with risk of BCR overall (HR = 1.00, 95% CI: 0.98–1.03; P = 0.848) for pN0 (HR = 0.99, 95% CI: 0.97–1.03; P = 0.916) or pN1 patients (HR = 0.96, 95% CI: 0.88–1.06; P = 0.468). Overall, PSA (HR = 1.02, P<0.001) and biopsy Gleason sum ≥ 8 (HR = 1.81, P = 0.001) were associated with an increased risk of BCR, and increasing LNY increased the likelihood of detecting>2 positive lymph nodes (OR = 1.27, 95% CI: 1.06–1.65, P = 0.023).

Conclusion

Seminal vesicle invasion is associated with an increased risk of BCR at 3 years, primarily due to pathologic Gleason score and PSA. Although greater lymph node yield is diagnostic and facilitates more accurate pathologic staging, our data do not show a therapeutic benefit in reducing BCR.

Introduction

The presence of seminal vesicle invasion (SVI) is a poor prognostic factor for patients with prostate cancer (PC) undergoing radical prostatectomy (RP) [1]. Further, 5-year biochemical recurrence (BCR) rates have been reported to range from 53% to 86% [2], [3] and, at 10-years, 65% in men with SVI and N0 disease [4], [5] Additionally, men with SVI at the time of RP are more likely to have other poor pathologic features, such as extracapsular extension and positive surgical margins, also known to independently increase BCR [6], [7] As patients with these pathologic features are closely followed and often offered salvage therapy, a modification in surgical technique that reduces risk of BCR would reduce the need for secondary interventions. Further, the presence of lymph node involvement found in roughly 24% of SVI patients is associated with even worse BCR outcomes, and lymph node resection may potentially further reduce the need for salvage intervention [6], [7], [8].

Greater freedom from BCR has been variably noted in patients undergoing PLND during RP [9], [10], [11] In 2006, Joslyn and Konety [10] used the SEER database to report that increasing lymph node yield (LNY) reduced the 10-year prostate cancer specific mortality (PCSM). The study was limited due to the inability to adjust for hormonal therapy intervention. Subsequently, Briganti and associates [12] reported clear evidence of oncologic benefit to PLND. In distinction, Masterson and associates found no evidence of a therapeutic benefit of reducing BCR with more extensive PLND [11]. Kim et al. demonstrated a lack of benefit of LNY on BCR in intermediate- and high-risk patients. [13] Evidence of therapeutic benefit remains divided.

Because of their increased risk for BCR, we propose that men with SVI are a good population to model [14], [15] whether increasing lymph node yield could have a therapeutic benefit. The present study is the first to analyze whether greater LNY during RP in men with SVI results in improved BCR rates.

Section snippets

Study data and population

Between 1990 and 2015, 289 patients with SVI (pT3b) PCa underwent RP at 2 academic institutions. High-volume institutions were selected such that variation between surgeon and surgical technique would be mitigated. Standard clinical and pathological characteristics were prospectively collected and entered into electronic databases at their respective institutions, under approved institutional review board protocols. Prior to transmission to the principal investigator (KB), datasets were

Clinical and pathologic characteristics

A total of 220 patients who met the study criteria were included in the analysis. Median patient age was 64 (IQR: 59.1–68.0) years and median PSA was 9.2 ng/mL (IQR: 6.2–17.1). Median lymph nodes sampled were 7 (IQR: 3–12); the median number of nodes removed at center 1 (KKB) was 7 (IQR: 4–12), while at center 2 (TA) was 5 (IQR: 2–13). The Kruskall-Wallis test revealed no significant statistical difference (P = 0.2). Pathologic Gleason sum 9 to 10 was found in 68 (30.9%) patients, 14 (6.4%)

Discussion

The therapeutic role of PLND (whether standard or extended) is controversial [17], [18], [19], [20], [21] Numerous reasons for this controversy exist due to a wide range of variables. Historically, one confounding issue is many men with a low risk of recurrence undergoing PLND; hence, demonstrating a therapeutic effect for PLND requires a very high number of subjects followed closely for several years [22]. As such, we selected men with SVI for the following reasons. Chief among these reasons

Conclusion

Seminal vesicle invasion at RP is associated with a high risk of BCR at 3 years.

Pathologic Gleason score is the primary risk factor for BCR in SVI patients. Although greater lymph node yield is more diagnostic and facilitates more accurate pathologic staging, it does not appear to be therapeutic for untreated high-risk patients, as 3-year freedom from BCR was unaffected by lymph node yield. Remarkably, the 21 men who did not undergo LND had very similar risk of BCR as compared to the 199 men

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