TABLE 1. Nomograms for predicting the lymph node involvement in prostate cancer 440 Study Cagiannos et al [42] Kattan et al [4,10,11,33,51] Makarov et al [12] Briganti et al [13,41,53,55] Briganti et al [13,41,53,55] Bluestein et al [14] Bishoff et al [43] Narayan et al [44,45] Conrad et al [54,15] Roach et al [45] Crawford et al [9,46,47] Batuello et al [46,47] Han et al [8,47,48] Poulakis et al [49] Karam et al [50] Wang et al [51] No. of patients 7,014 697 5,730 602 278 1,632 481 932 344 212 4,133 6,135 5,744 201 425 411 Predictors PSA, clinical stage, biopsy Gleason score PSA, clinical stage, biopsy Gleason score PSA, clinical stage, biopsy Gleason score PSA, clinical stage, biopsy Gleason score PSA, clinical stage, biopsy Gleason score, percentage of positive cores PSA, clinical stage, biopsy Gleason score PSA, clinical stage, biopsy Gleason score PSA, biopsy Gleason score No. of positive biopsies, no. of biopsies containing any Gleason grade 4 or 5 cancer PSA, biopsy Gleason score PSA, clinical stage, biopsy Gleason score PSA, clinical stage, biopsy Gleason score PSA, clinical stage, biopsy Gleason score, age PSA, clinical biopsy Gleason score, and pelvic coil MRI findings PSA, clinical stage, biopsy Gleason score, preoperative plasma endoglin PSA, clinical biopsy Gleason score, and pelvic coil MRI findings PLND: pelvic lymph node dissection, LNI: lymph node invasion, PSA: prostate-specific antigen, MRI: magnetic resonance imaging, NA: not available TABLE 2. Guidelines for determining the need for and extent of pelvic lymph node dissection for treating prostate cancer Guidelines European Association of Urology American Urological Association National Comprehensive Cancer Network Indication for PLND Men with intermediate (cT2a, PSA 10-20 ng/ml, biopsy Gleason score 7) or high-risk (＞cT2b, PSA ＞20 ng/ml, Gleason score ≥8) prostate cancer PLND generally reserved for patients with higher risk of nodal involvement PLND can be excluded in patients with ＜7% predicted probability of lymph node metastases by nomograms although some patients with nodal metastases will be missed. An extended PLND is preferred when PLND is performed PLND: pelvic lymph node dissection, PSA: prostate-specific antigen tients qualified as low-risk patients, and only 9% (71 pa- tients) were LN-positive and ePLND was performed in only 23% of patients. The necessity for PLND has been questioned, particularly in low-risk groups, on the basis of studies of lPLND. On the contrary, studies with ePLND have shown that LN meta- stases can occur even in patients with a PSA level ＜10 ng/ml. Schumacher et al showed that following ePLND and radical prostatectomy in patients with PSA ＜10 ng/ml, there was a 25% incidence of LN metastases in those with a specimen Gleason score ≥7, whereas only 3% of patients with a Gleason score ≤6 were node-positive [59]. Heiden- reich et al reported a 2.4% incidence of LN metastasis in patients with a PSA level ＜10.5 ng/ml and biopsy Gleason scores ≤6, whereas Bhatta-Dhar et al found that the LN metastasis risk was ＜1% after lPLND in a series of pa- Korean J Urol 2011;52:437-445 tients with organ-confined disease, PSA ＜10 ng/ml, and a biopsy Gleason score ≤6 [31,60]. However, the inherent risk of understaging, which is approximately 30% [61], has to be taken into account. In the study of Bhatta-Dhar et al, 40% of patients had their Gleason scores upgraded to ＞6 [60]. 　Expert panels from the American Urological Associa- tion, National Comprehensive Cancer Network, and European Association of Urology have created guidelines for PLND based on such nomograms and other available data (Table 2). In summary, several well-known nomo- grams can be used to accurately predict who is at risk for LN-positive prostate cancer and to potentially predict who might derive therapeutic benefit from PLND. However, by depending on these nomograms, we may fail to properly stage patients with apparently low-risk disease because Extent of Prevalence of Predictive PLND LNI, % accuracy, % Limited Limited Limited Extended Extended Limited Limited Limited Limited Limited Limited Limited Limited Limited Limited Limited 3.7 8 1 11 10.4 7.7 11 8.1 17 4.6 5 10 3.3 5 Joung et al 76 76.8 88 76 83 81 88 91 97.8 89.2 Extent of PLND Extended Not indicated Extended