Spontaneous necrosis in osteosarcomas.

In the treatment of osteosarcoma pre-operative chemotherapy has assumed considerable importance in helping improve survival, and enabling limb-sparing procedures. The quantitative assessment of tumour necrosis in the resected specimen by morphological means has become a significant step in judging therapeutic response and in helping determine post-operative management. Different systems of grading tumour regression have been proposed. Little is known, however, about the morphology or degree of spontaneous necrosis in osteosarcomas, in particular to what extent necrosis can be considered to be due to cytotoxic treatment. For this purpose, 13 osteosarcomas, taken from patients treated by surgery alone, were examined by the same method we routinely employ in assessing chemotherapeutic response. The results demonstrate that the extent of spontaneous necrosis does not approach that achieved in response to chemotherapy. Sub-total necrosis may be due to spontaneous regression, inadequate therapeutic response, or to a combination of both. Hence, only two categories of response, good and poor, appear relevant and these terms should be used in preference to good, intermediate and poor.