PREDICTIVE FACTORS FOR LOCAL RECURRENCE IN OSTEOSARCOMA - 540 PATIENTS WITH EXTREMITY TUMORS FOLLOWED FOR MINIMUM 2.5 YEARS AFTER NEOADJUVANT CHEMOTHERAPY

We investigated predictive factors for local recurrence in 540 patient s with non-metastatic osteosarcoma of the extremity treated with surge ry and neoadjuvant chemotherapy, between March 1983 and October 1994. The median follow-up was 7.5 (2.5-15)years. Local recurrences develope d in 31 (6%) patients after a median time of 2 (0.5-7) years. Local re currence did not correlate with patients' age and sex, histologic subt ype, site and tumor volume, presence of pathologic fracture, chemother apy regimen and type of surgery. Local recurrence-free survival (LRFS) correlated with the quality of surgical margins and response to chemo therapy: the 7-year LRFS was 97% after adequate surgical margins and 7 1% after inadequate surgical margins (9 < 0.0001), and was 95% in good responders and 90% in poor responders (0 = 0.001). Only 1 of 31 patie nts with local recurrence was free of disease 15 months after the last treatment, 3 were alive with uncontrolled disease and 27 died. This p ost-relapse outcome is significantly worse than in patients who relaps ed with metastases only (25% free of disease, 0.5-9 years after the la st treatment). We conclude that, in osteosarcoma of the extremity, lim b-salvage procedures should be planned only when the preoperative stag ing indicates that it is possible to achieve adequate surgical margins . If the pathologic examination of the surgical specimen shows inadequ ate surgical margins, an immediate amputation should be considered, es pecially if the histologic response to preoperative chemotherapy was p oor.