The Prognostic Significance of Nuclear DNA Content in Chondrosarcoma

The nuclear DNA content in 48 chondrosarcomas and 4 chondromas was determined. Grading according to O'Neal-Ackerman was also performed. All chondromas were found to be diploid (normal nuclear DNA content). Twenty-two of the chondrosarcomas showed the same DNA distribution curve as the chondromas and were characterized as diploid, while 26 were found to be hyperploid (increased nuclear DNA content). A comparative study of grade and ploidy in relation to ten-year survival and metastasis rates showed that ploidy determinations in chondrosarcomas give significant prognostic information, even better than that obtained by conventional histopathologic grading. In this study, diploid chondrosarcomas were found to be associated with a significantly more favorable clinical course than were hyperploid chondrosarcomas. The prognostic relevance of these ploidy determination was further confirmed by analyzing the ploidy level of selected cases characterized bydifferent clinical courses. Thus, the tumors from 13 (93%) of 14 patients with a highly malignant clinical course (death within two years) and the tumors at the primary site in 17 (81%) of 21 metastasizing chondrosarcomas were found to be hyperploid. Direct measurements on four metastases revealed that all were hyperploid.