Objectives: To determine if the number of lymph nodes (LNs) removed is an independent predictor of biochemical recurrence (BCR) in patients without LN metastases undergoing radical prostatectomy (RP).
Material and methods: Retrospective analysis of 7,310 patients treated at 7 centers with RP and pelvic LN dissection for clinically localized prostate cancer between 2000 and 2011. Patients with LN metastases (n = 398) and other reasons (stated later in the article) (n = 372) were excluded, which left 6,540 patients for the final analyses.
Results: Overall, median biopsy and RP Gleason score were both 7; median prostate specific antigen level was 6 ng/ml (interquartile range [IQR]: 5); and median number of LNs removed was 6 (IQR: 8). A total of 3,698 (57%), 2,064 (32%), and 508 (8%) patients had ≥ 6, ≥ 10, and ≥ 20 LNs removed, respectively. Patients with more LNs removed were older, had a higher prostate specific antigen level, had higher clinical and pathologic T stage, and had higher RP Gleason score (all P<0.002). Within a median follow-up of 21 (IQR: 16) months, more LNs removed was associated with an increased risk of BCR (continuous: P = 0.021; categorical: P = 0.014). In multivariable analyses that adjusted for the effects of standard clinicopathologic factors, none of the nodal stratifications predicted BCR.
Conclusions: The number of LNs did not have any prognostic significance in our contemporary cohort of patients with LN-negative prostate cancer. This suggests that the risk of missed clinically significant micrometastasis may be minimal in patients currently treated with RP and having a lower LN yield.
Keywords: Biochemical recurrence; Lymph node metastasis; Nodal yield; Pelvic lymph node dissection; Prostate cancer.
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