Development of nomogram to non-steroidal antiandrogen sequential alternation in prostate cancer for predictive model.

Objectives: To clarify clinical predictors for a prostate-specific antigen decrease � 50% in response to alternative non-steroidal antiandrogen therapy and to develop a nomogram to predict the prostate-specific antigen decrease � 50% in response to alternative non-steroidal antiandrogen therapy in patients with advanced prostate cancer that relapsed after initial combined androgen blockade. We previously reported that combined androgen blockade with an alternative non-steroidal antiandrogen is effective for advanced prostate cancer that has relapsed after initial combined androgen blockade. Methods: We enrolled 161 patients from 14 medical institutions with histologically confirmed prostate cancer who had been treated with combination therapy and in whom cancer progressed after first-line combined androgen blockade therapy. A nomogram for the prostatespecific antigen decrease � 50% from baseline prostate-specific antigen in response to alternative non-steroidal antiandrogen therapy was developed based on the final logistic regression model. Results: Overall prostate-specific antigen decreased � 50% in 75 of 161 patients (46.6%) in response to alternative non-steroidal antiandrogen therapy. Using five independent risk factors (initial serum level of prostate-specific antigen, hemoglobin, C-reactive protein, prostate-specific antigen nadir to second hormone therapy and Gleason sum), a nomogram was developed for the prediction of prostate-specific antigen decrease � 50% in response to alternative nonsteroidal antiandrogen therapy. The receiver operating characteristic curve showed that the accuracy of the predicted probability was 72.5% for the model. Conclusions: This predictive nomogram could predict the prostate-specific antigen decrease � 50% in response to alternative non-steroidal antiandrogen therapy and might be of benefit to determine the sequential treatment strategy in patients with relapse after first combined androgen blockade.