[Prognosis based on stereological study of neoplastic osteoid classification in osteosarcoma].

The diagnostic criteria of neoplastic osteoid were established by means of stereological study of 70 cases of osteosarcoma. According to the different histological features, the authors suggest that osteosarcomas are to be classified into three types: Type I (mature osteoid type), Type II (intermediate differentiated osteoid type) and Type III (immature osteoid type). 50 patients out of the 70 had been followed up for years. The five-year survival rate in 12 patients with Type I was 92%; in 18 patients with Type II and 20 patients with Type III, none of them survived more than five years after operation. Statistically significant difference was found between individuals with Type I and Type II, or with Type I and Type III. However, there was no statistically significant difference between the histological types according to Dahlin. The results showed that our classification given in this paper may be preferable to the Dahlin's for evaluation of prognosis.