Prognostic stratification of patients with non-metastatic osteosarcoma may improve the clinical management and the design of clinical trials.

Data from 773 patients [median age 15 years (3-40)] treated at our Institute from 1983 to 2000 with high-dose methotrexate, cisplatin, doxorubicin and ifosfamide (neoadjuvant chemotherapy) were analyzed. After multivariate analysis including age, site, tumour volume (cut-off 200 mL), serum LDH and Alkaline Phosphatase (SAP), histology (osteoblastic and chondroblastic vs others), high LDH and SAP, osteoblastic and chondroblastic histotypes resulted independent prognostic factors of DFS.

Patients were grouped according to a score from 0 (absence) to 3 (one to 3 adverse factors). The scoring system was implemented by the addition of PgP expression and grade of chemotherapy-induced necrosis.

A score of 0, 1, 2, 3 was given to 14%, 38%, 32% and 16% of patients respectively.10-year DFS was 80% (95%CI 72-89) for score of 0, 58% (95%CI 52-64) for 1, 53% (95%CI 46-59) for 2 and 40% (95%CI 32-50) for 3 (p= 0.001). PgP expression (168 patients) identified patients with 100% probability of DFS (score of 0 and negative PgP) and patients with 18% (95%CI 52-64) DFS (score of 3 and positive PgP).

Good (GR) and poor responder (PR) patients had the same probability of DFS in case of score of 0 [GR82% (95% CI 72-91), PR79% (95% CI 65-93)] and score of 3 [GR43% (95% CI 32-55) PR36% (95% CI 21-51)]. Different probability of DFS in case of score of 1 [GR64% (95% CI 57-72) PR47% (95% CI 36-59)] and score of 2 [GR63% (95% CI 55-71) PR36% (95% CI 21-51)].

It is possible to stratify outcomes of patients with non metastatic osteosarcoma of the extremity by means of a simple score based on easily available clinical parameters. This scoring system is worth to be validated on larger series.