Fig. 1

Rising PSA is a common phenomenon during the first 12 weeks of Abiraterone therapy followed by either continued rising PSA representing true disease progression or delayed PSA-decline representing response to therapy. ALP-Bouncing, occurring in 40 % of the studied patients with bmCRPC happens at a very early stage of antihormonal therapy and is defined as rapidly rising ALP-levels independent of baseline-ALP during the first 2–4 weeks of therapy with subsequent, equally marked, decline to pretreatment levels or better no later than 8 weeks after initiation of therapy. This can precede potentially delayed PSA-declines. This phenomenon does not occur in a uniform way