Abstract 1508P
Background
The prognostic role of pre-treatment serum alkaline phosphatase (SAP) in patients with osteosarcoma has been investigated in previous studies, but the results are inconsistent. The purpose of this study was to evaluate prognostic factors, especially pre-treatment SAP level, in adolescent and adult patients with localized extremity osteosarcoma.
Methods
In this retrospective study, 153 patients with high-grade, localized extremity osteosarcoma, treated from 1995 to 2011 were analyzed. Pre-treatment SAP and lactate dehydrogenase (LDH) levels and other clinicopathological data were recorded. Arbitrarily, the group of patients with high SAP was further divided into 3 subgroups: up to 2 times of upper limit normal level; from 2 times to 4 times; higher than 4 times of upper limit normal level.
Results
The median age was 19 years (range 13-68), 99 patients (64.7%) were male. The most common primary site was femur (89 patients, 58.2%). The most common histological subtype was osteoblastic (56 patients, 47.0 %), 42.5 % of patients had high pre-treatment SAP levels, 43.1 % of patients had high LDH levels. Median follow-up time was 36 months (4-213). Disease-free survival (DFS) at 5 and 10 years were 42.5 % and 37.1 %, respectively, (median DFS: 36 months); overall survival (OS) at 5 and 10 years were 59.6 % and 50.6 %, respectively, (median OS: 146 months. Univariate analysis for OS showed that male gender (p=0.019), high LDH level (p=0.015), high SAP levels (p=0.011) , presence of tumor positive margins after primary surgery (p=0.004) and tumor necrosis rate (p=0.06) were associated with poor survival. In multivariate analysis, only SAP level higher than 4 times of upper limit normal level (p<0.001) and poor tumor necrosis after preoperative chemotherapy (p=0.026) were found to be significantly associated with poor OS.
Conclusions
Pre-treatment SAP level higher than 4 times of upper limit normal level has poor prognostic role in adolescent and adult patients with localized extremity osteosarcoma. Further studies with larger number of patients are needed to determine the most accurate threshold point of high SAP levels as prognostic factor.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.