LOCAL HOST RESPONSE IN OSTEOSARCOMA AFTER CHEMOTHERAPY REFERRED TO RADIOGRAPHS, CT, TUMOR NECROSIS AND PATIENT SURVIVAL

Purpose: The necrotic effect of chemotherapy on primary osteosarcoma h as been shown to be predictive of the final outcome. Little attention has been paid to the local response of the host (LHR), which reflects the tumour-host relationship. Design: A four-step grading system was d eveloped based on distinct histological patterns of the LHR around the lesion. These responses were correlated with the chemotherapy-induced necrosis or chemosensitivity and analysed in an attempt to ascertain their influence on the patient prognosis. The ability of conventional radiographs and computed tomography to measure LHR was studied. Method s: The grading system was applied to macroslides of specimens obtained from 72 patients with stage II B primary osteosarcoma in various limb s after wide resection and complete courses of pre- and postoperative chemotherapy who were treated between 1985 and 1991 with a median foll ow-up of 5 years and 9 months. The histological specimens were blindly reviewed by two pathologists and two experienced musculoskeletal onco logists to assign a grade of response. The results were correlated wit h tumour necrosis, patient survival and response features on conventio nal radiographs and CT images, Results: Significant correlation was fo und between LHR and tumour necrosis or chemosensitivity (r = 0.55) and between LHR and CT response (r = 0.56). There was no correlation betw een LHR and the findings on conventional radiographs. A grade 4 LHR wa s predictive of long-term survival. Conclusions: The LHR to preoperati ve chemotherapy has a prognostic influence on patient survival and can be predicted by CT.