IMPROVED PREDICTABILITY OF EXTRACAPSULAR EXTENSION AND SEMINAL-VESICLE INVOLVEMENT BASED ON CLINICAL AND BIOPSY FINDINGS IN PROSTATE-CANCERIN JAPANESE MEN

Objectives. The accurate preoperative prediction of the extent of canc er by pathologic examination is essential for choosing the optimal tre atment for patients with prostate cancer. Currently available clinical staging methods are not adequate and more precise staging is required . Methods. Using the log likelihood ratio test and receiver operating characteristic (ROC) curve analysis, preoperative variables, including biopsy pathologic findings, were assessed for predicting final pathol ogic stage in prostate cancer. A multivariate model for predicting dis ease organ confinement status was established for easy clinical use. R esults. The use of the number of cores with cancer and maximum cancer length in conjunction with the three variables (prostate-specific anti gen, clinical stage, and biopsy Gleason score) was found to significan tly improve predictability of extracapsular extension and seminal vesi cle involvement in clinically resectable (n = 96) and localized prosta te cancers (n = 81) (P <0.05). Areas under ROC curves for the above tw o parameter sets (five- versus three-variable model) were 0.8395 and 0 .7109, respectively, for capacity for extracapsular extension predicti on in clinically localized cancer. These values for seminal vesicle in volvement were 0.7861 and 0.6927, respectively. The logistic model gav e positive and negative predictive Values of 73% and 78%, and 64% and 83%, respectively, for extracapsular extension and seminal vesicle inv olvement in clinically localized cancer at a predicted probability of 0.5 or greater. Conclusions. The present method may be used to predict non-organ-confined prostate cancer with greater accuracy than the pre viously reported model using three variables. UROLOGY 52: 433-440, 199 8. (C) 1998, Elsevier Science Inc. All rights reserved.