COMPARISON OF THE OUTCOME OF CONVENTIONAL OSTEO-SARCOMA AT TWO SPECIALIST INTERNATIONAL ORTHOPAEDIC ONCOLOGY CENTRES

Abstract

Current survival rates for cancer in the UK are perceived to be worse than those in mainland Europe. In order to asses this we investigated the prognostic value of patient and treatment parameters in the management of osteosarcoma, and whether these parameters are equally important across international boundaries.

Retrospective, cross-sectional study of patients (n=428) diagnosed with non metastatic distal femur or proximal tibia osteosarcoma, between 1990–1997 at two specialist orthopaedic oncology centres; Birmingham, UK and Bologna, Italy. Disease free survival (DFS) and overall survival (OS) were assessed by Kaplan-Meier, Fisher’s PLSD and Cox proportional hazard regression. Results : DFS and OS were 43% and 60% at 5 years in Centre 1 and 56% and 73% at Centre 2 respectively. Median survival was 108 weeks at Centre 1 and 136 weeks at Centre 2. A significant difference in DFS and OS was demonstrated between the centres (p=0. 0019 and p=0. 0280 respectively). The most important prognosticators were raised alkaline phosphatase (p=0. 002 and p=0. 0019), degree of chemotherapy induced necrosis (p=0. 0001 and p=0. 0002) and tumour volume > 150cm³ (p=0. 0037 and p=0. 0057).

The most significant combination of prognosticators was alkaline phosphatase and tumour necrosis. 75% of patients in centre 2 had a good chemotherapy response (> 90% necrosis) compared to only 29% in Centre 1. The other prognostic indicators were evenly matched. Chemotherapy regime was found to have significantly different outcome in DFS and OS.

This is a retrospective study designed to explore possible reasons for differences in survival between two international centres. It would appear that all known patient factors were matched between the centres but that the main difference was in the effectiveness of chemotherapy. Further international prospective studies are needed to confirm these findings.