[Comparison of x-ray and histological findings in osteosarcomas following preoperative chemotherapy]

Since the introduction of pre-operative chemotherapy, osteosarcomas have shown a more favourable prognosis. Reaction of the tumour due to chemotherapy is judged pre-operative primarily by radiology (plain films, angiography, CT, scintigraphy). There is little evidence concerning the radiological appearances after pre-operative chemotherapy and morphological changes, particularly in respect of tumour regression. Specific radiological changes were therefore compared with pathological findings following chemotherapy and operation in 17 patients with osteosarcomas. Tumours were examined which showed radiological evidence of intra-and extra-osseous sclerosis or lysis and which still were classified as vital tumour tissue. Tumour planes were reconstructed from large histological sections of the operative specimen and compared with the radiological appearances. Sclerosis was found to be due to reactive new bone formation or to mineralisation of the osteosarcomatous tissue. Lysis correlated with persistent vital tumour, or in connective tissue. Nine out of ten cases, regarded as vital on radiological evidence, showed vital tumour cells on histological section. Lyses and scleroses were not reliable indications of the pre-operative state of the osteosarcoma following chemotherapy. On the other hand, combined qualitative radiological criteria for assessing tumour vitality, proved to be helpful.