Artificial neural network model for the assessment of lymph node spread inpatients with clinically localized prostate cancer

Objectives. To develop an artificial neural network (ANN) model to predict lymph node (LN) spread in men with clinically localized prostate cancer aci d to describe a clinically useful method for interpreting the ANN's output scores. Methods, A simple, feed-forward ANN was trained and validated using clinica l and pathologic data from two institutions (n = 6135 and n = 319). The cli nical stage, biopsy Gleason sum, and prostate-specific antigen level were t he input parameters and the presence or absence of LN spread was the output parameter, Patients with similar ANN outputs were grouped and assumed to b e part of a cohort, The prevalence of LN spread for each of these patient c ohorts was plotted against the range of ANN outputs to create a risk curve. Results. The area under the receiver operating characteristic curve for the first and second validation data sets was 0.81 and 0.77, respectively, At an ANN output cutoff of 0.3, the sensitivity achieved for each validation s et was 63.8% and 44.4%; the specificity was 81.5% and 81.3%; the positive p redictive value was 13.6% and 6.5%; and the negative predictive value was 9 8.0% and 98.1%, respectively. The risk curve showed a nearly linear increas e (best fit R-2 = 0.972) in the prevalence of LN spread with increases in r aw ANN output. Conclusions, The ANN's performance on the two validation data sets suggests a role for ANNs in the accurate clinical staging of patients with prostate cancer. The risk curve provides a clinically useful tool that can be used to give patients a realistic assessment of their risk of LN spread. UROLOGY 57: 481-485, 2001. (C) 2001, Elsevier Science Inc.