A nomogram is more accurate than a regression tree in predicting lymph node invasion in prostate cancer.
OBJECTIVE
To compare the performance and discriminant properties of two instruments (a tree-structured regression model and a logistic regression-based nomogram), recently developed to predict lymph node invasion (LNI) at radical prostatectomy (RP), in a contemporary cohort of European patients.


METHODS
The cohort comprised 1525 consecutive men treated with RP and bilateral pelvic LN dissection (PLND) in two tertiary academic centres in Europe. Clinical stage, pretreatment prostate-specific antigen (PSA) level and biopsy Gleason sum were used to test the ability of the regression tree and the nomogram to predict LNI. Accuracy was quantified by the area under the receiver operating characteristic curve (AUC). All analyses were repeated for each participating institution.


RESULTS
The AUC for the nomogram was 81%, vs 77% for the regression tree (P = 0.007). When data were stratified according to institution, the nomogram invariably had a higher AUC than the regression tree (Hamburg cohort: nomogram 82.1% vs regression tree 77.0%, P = 0.002; Milan cohort: 82.4% vs 75.9%, respectively; P = 0.03).


CONCLUSIONS
Nomogram-based predictions of LNI were more accurate than those derived from a regression tree; therefore, we recommend the use of nomogram-derived predictions.
Briganti
Alberto
A
Department of Urology, Vita-Salute University, Milan, Italy.
Gallina
Andrea
A
Suardi
Nazareno
N
Chun
Felix K-H
FK
Walz
Jochen
J
Heuer
Roman
R
Salonia
Andrea
A
Haese
Alexander
A
Perrotte
Paul
P
Valiquette
Luc
L
Graefen
Markus
M
Rigatti
Patrizio
P
Montorsi
Francesco
F
Huland
Hartwig
H
Karakiewicz
Pierre I
PI
D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003663:Decision Trees; D005060:Europe; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D049451:Nomograms; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy / Q000379:methods; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery; D012015:Reference Standards; D012044:Regression Analysis
D017430:Prostate-Specific Antigen