Prognostic significance of spontaneous tumour necrosis in osteosarcoma.

Preoperative chemotherapy is an integral part of the management of osteosarcoma, and the extent of tumour necrosis found at operation is an important prognostic variable. Knowledge about spontaneous, pretherapy necrosis is difficult to obtain but provides important quantitative information about the necrotic effect of chemotherapy. Using three different methods, we studied spontaneous tumour necrosis in 20 localized intramedullary osteosarcomas of the distal femur diagnosed between 1963 and 1972. All patients received surgical treatment only. All six patients with spontaneous necrosis involving more than 20% of tumour died. Five of 14 patients with necrosis amounting to less than 20% were long-term, disease-free survivors. The extent of necrosis was independent of tumour size. Two semiquantitative methods of evaluation were easily applied and reproducible. Spontaneous necrosis in untreated osteosarcomas occurs frequently; extensive necrosis may indicate a rapid clinical course. Tumour necrosis can be quantified reliably in clinical work.