Pelvic Lymph Node Dissection in Prostate Cancer these nomograms rely on data collected from patients who only underwent lPLND. Overall, the existing data suggest that it may be possible to refrain from performing PLND on low-risk patients with a PSA ＜10 ng/ml and a biopsy Gleason score ≤6, but the inherent risk of biopsy-based un- derstaging should be kept in mind. THERAPEUTIC ROLE OF PLND Aside from providing clinicians with the most accurate LN staging, the therapeutic role of PLND in prostate cancer is another main issue. Some evidence suggests that ePLND might also have a positive impact on survival. Early studies suggested that radical prostatectomy and removal of in- volved regional LNs was beneficial for survival [62,63]. A subsequent study confirmed a 68% 10-year metastasis- free survival rate in patients with LN micrometastasis who were managed without adjuvant therapy [64], indicating that radical prostatectomy with PLND could be curative even for LN-positive disease. Theoretically, these results are supported by the fact that meticulous nodal resection removed micrometastases not detected by routine patho- logic examination, which may in part be explained im- munohistochemically [65]. The latter study was a careful review of 3, 914 negative nodes from 274 pT3 patients by immunohistochemical staining. The authors reported that 13.3% of 180 patients who were originally defined as being N0 actually harbored occult LN metastasis. These patients had significantly poorer survival rates than did patients who were truly LN-negative and had outcomes comparable to men who had been LN-positive on initial staging. Ferrari et al used a real-time polymerase chain reaction (PCR) as- say that revealed and quantified occult micrometastases in pathologically negative LNs before primary therapy for prostate cancer [66]. Terakawa et al also found that re- al-time PCR increased the detection rate of LNI by more than three-fold compared with routine immunohistoche- mistry [67]. These authors also demonstrated a statistical correlation between occult (real-time PCR-detected) LNI and patient outcomes. 　With respect to the correlation between the burden of positive node removal and prognosis following radical pros- tatectomy and PLND, Bader et al determined the pro- gression and survival rates of 92 patients with positive no- des following radical prostatectomy and ePLND without adjuvant therapy [32]. Following a median follow-up of 45 months, 15 of 39 patients (38.5%) with a single positive node did not show signs of progression, whereas only 10% and 14% of patients with two or more positive LNs, re- spectively, remained disease free. Other studies reported the possibility of long-term survival despite the presence of limited LN metastasis with PLND and poorer prognosis with greater LN invasion [8,28,68-72]. Daneshmand et al reported that patients who had one or two positive LNs had a clinical recurrence-free survival rate of 70% and 73%, re- spectively, after 10 years compared with men with five or more involved nodes, who had a recurrence-free survival 441 rate of only 49% [68]. A positive node density ＜20% was associated with improved disease progression rates and survival. Allaf et al reported that among men with LN-pos- itive disease involving ＜15% of extracted nodes, the 5-year PSA progression-free rate for ePLND was 43% compared with 10% for the more limited PLND [69]. Boorjian et al ret- rospectively reviewed a large series of patients with pos- itive LNs after radical prostatectomy and PLND with a lim- ited number of nodes (median 11) removed and found that 56% of the patients had a 10-year biochemical pro- gression-free survival period. A solitary LN metastasis in- creased the risk of cancer-specific death almost four-fold; in patients with two or more positive LNs, this was in- creased two-fold compared with patients with only one pos- itive node [71]. Palapattu et al found that 52% of men with a positive node density of ＜15%, a Gleason score ≤7, and no seminal vesicle invasion remained free of biochemical failure after 5 years [72]. 　Furthermore, in patients with pN0 prostate cancer, Masterson et al found that an increased number of nodes removed significantly correlated with the absence of bio- chemical recurrence [73]. Similarly, Joslyn and Konety, us- ing the SEER database, revealed that when age, race, stage, grade, and radiotherapy were controlled for, the risk of cancer-specific death was significantly lower (23%) for patients who had more than four LNs removed [70]. Furth- ermore, more extensive lymphadenectomy (＞10 nodes re- moved) was associated with a 15% lower risk of prostate cancer death even after the analysis was restricted to pa- tients with negative lymph nodes. Early data from a recent case-control series by Heidenreich et al [28] also demon- strated a therapeutic benefit of ePLND. By comparing a co- hort of 100 consecutive patients with pN0 disease who un- derwent lPLND with a group of 100 consecutive patients who underwent ePLND with minimum of 5 years of fol- low-up, the initial data obtained indicated a PSA relapse rate of 23% in the lPLND group compared with 8% in the ePLND group. 　In contrast, other studies could not define the ther- apeutic role of PLND in prostate cancer. Bhatta-Dhar et al did not show any benefit of PLND. They retrospectively re- viewed 336 patients with favorable tumor characteristics such as PSA levels of 10 ng/ml or less, biopsy Gleason scores ≤6, and clinical stage of T1 or T2 [60]. They determined that the 6-year biochemical relapse-free rate was not sig- nificantly different between patients who underwent PLND and those who did not. However, this study had some limitations including an absence of randomization, the lack of removal of internal iliac nodes (which is crucial in PLND), and the fact that the cohort was confined to only patients with a low risk for LN metastasis. DiMarco et al did not find improvement in prostate cancer outcomes with increasing LN yield between lPLND and ePLND in an ad- juvant therapy-free cohort of 7,036 pN0 patients [74]. More recent data from Murphy et al corroborated that LN yield was not a predictor of biochemical recurrence in pN0 pa- tients, even when the patients were stratified into high- Korean J Urol 2011;52:437-445