Pre- and post-chemotherapy alkaline phosphatase levels as prognostic indicators in adults with localised osteosarcoma

Abstract 

The prognostic value of alkaline phosphatase (AP) measured before and after chemotherapy, but before surgery was established in a retrospective survey of patients. The patients were 18 years or older, with non-metastatic high-grade osteosarcoma. Pre-chemotherapy AP was available in 89 cases, post-chemotherapy AP in 86 patients, and both in 71 cases. AP was classified as Normal (<100% upper limit), High (100%⩽AP<200%) or Very High (AP⩾200%). Osteosarcoma subtype was predominantly conventional. No correlation was found between subtype and chemotherapy response, local recurrence or survival. Pre-chemotherapy AP was raised more in the osteoblastic subtype. Post-chemotherapy AP and normalisation were the same among different subtypes. AP was not correlated with local recurrence. Normal or High pre-chemotherapy AP correlated with better survival at 10 years (64% and 70%) than Very High pre-chemotherapy AP (37%, P=0.005). Post-chemotherapy AP correlated with survival (68%, 39% and 25% in the Normal, High and Very High group, P=0.0007) and response to chemotherapy (P=0.049). A pre-chemotherapy AP above twice Normal correlated with worse survival. If AP decreased after chemotherapy, but was still raised, survival was better, but still worse than if AP normalised. A raised post-chemotherapy AP predicts poor chemotherapy response.

Keywords: Osteosarcoma, Adult, Prognosis, Alkaline phosphatase, Subtype, Response to chemotherapy, Survival, Local recurrence