Survival markers related to bone metastases in prostate cancer

Prognostic value of a bone resorption marker, tartrate-resistant acid phosphatase isoform 5b (TRACP 5b), and two matrix metalloproteinases (MMP-2 and MMP-9) was compared with the standard clinical analyses of total alkaline phosphatase (tALP) and prostate-specific antigen (PSA), in prostate cancer (PC) patients with (BM+) or without (BM-) bone metastases. Diagnostic accuracy evaluation showed the highest area under the curve for tALP (AUC=0.98), followed by PSA (AUC=0.87), TRACP 5b (AUC=0.82), MMP-9 (AUC=0.62) and MMP-2 (AUC=0.53). Significantly shorter survival was observed for patients with tALP (p<0.001), TRACP 5b (p=0.002) and PSA (p<0.001) levels, above the determined cut-off values compared with lower marker levels. In multivariate Cox regression analysis, only tALP and PSA, in addition to Gleason score were independent prognostic factors for survival. Of the three novel markers tested, only TRACP 5b proved to be predictive of survival in PC with bone metastases. MMP-2 and -9 are thus not recommended for further studies in this context.