Morphological grades of regression in osteosarcoma after polychemotherapy - study COSS 80

The histologic grade of regression of 50 osteosarcomas after polychemotherapy - according to the protocol study, COSS 80 - was classified on a six-stage regression scale; 56% of all patients responded well to chemotherapy regression grades I, II, and III and no significant difference between BCD- and CPL-treated patients could be found. Tumors under 10 cm in length responded better to chemotherapy than those of greater length and there was a good correlation between the clinical estimation of tumor regression and progression and the histologic grade of regression.