Prognostic significance of serum alkaline phosphatase activity in canine appendicular osteosarcoma

Sixty-one dogs with appendicular osteosarcoma were treated with amputatibn and chemotherapy of cisplatin and doxorubicin. Serum samples were obtained before and after treatment for determination of total alkaline phosphatase (TALP) activity as well as the activities of the constituent bone (BALP), l iver (LALP), and corticosteroid-induced (CALP) isoenzymes. The relationship between alkaline phosphatase activities and survival was examined by Cox p roportional hazards regression analysis and Kaplan-Meier log rank analysis. Mean activity of TALP, BALP, and LALP decreased significantly after treatm ent (P < .001). TALP and LALP activities before treatment were significantl y correlated with survival (P = .006 and .001, respectively). The correlati on between BALP activity before treatment and survival approached significa nce (P =.054). CALF activity and TALP, BALP, and LALP activities after trea tment were not significantly correlated with survival. Dogs with normal pre treatment TALP and BALP activities survived significantly longer than dogs with increased pretreatment activities (P = .001 and .003, respectively). M edian survival times for dogs with normal or increased TALP activities befo re treatment were 12.5 and 5.5 months, respectively; and median survival ti mes for dogs with normal or increased BALP activities before treatment were 16.6 and 9.5 months, respectively. In the design of future clinical trials involving dogs with osteosarcoma, consideration should be given to stratif ying the randomization according to alkaline phosphatase activity. Ln addit ion, alkaline phosphatase activity should be a factor considered by clinici ans attempting to tailor the aggressiveness of adjuvant chemotherapy to the needs of individual patients or owners.