Comparison of quantitative ground substance analysis in biopsy and resected tumour in osteosarcomas

Osteosarcomas may show variable differentiation. They are divided into osteoblastic, chondroblastic and fibroblastic subgroups depending on their dominant histological differentiation. The pattern of histological differentiation of osteosarcoma is supposed to have an influence on the response to chemotherapy and in this study the relationship between the differentiation of the tumours and response to chemotherapy was examined in 22 osteosarcomas. For this purpose the nuclear size of tumour cells was determined on imprints and the area of the different ground substances on tumour sections after undecalcified preparation. Tumours with little nuclear polymorphism and those with an area of chondroblastic ground substance of more than 20% in the biopsy showed a poor response to chemotherapy. We conclude from our results that lack of nuclear polymorphism and in particular a large area of chondroblastic ground substances in the biopsy, can be regarded as an unfavourable prognostic factor in the response to primary chemotherapy. A comparison of the area of chondroblastic ground substance in biopsy and resection material proves that the biopsy delivers a representative view of the total area of chondroblastic ground substance for the groups of responder and non-responder. Patients with a large amount of chondroblastic ground substance in the biopsy probably require more aggressive chemotherapy.