Lack of prognostic significance of intratumoral angiogenesis in nonmetastatic osteosarcoma

Background A need exists to stratify patients with nonmetastatic osteosarcoma into risk subcategories to administer risk-adapted therapy. Intratumoral angiogenesis determined at diagnosis may have a prognostic significance in this malignancy. Patients and Methods The authors performed a retrospective immunohistochemical study on archival pathologic material from patients with nonmetastatic osteosarcoma, excluding patients with purely chondroblastic tumors associated with hypovascularity of the cartilaginous stroma. Representative sections from the diagnostic biopsies were stained with a murine monoclonal antibody directed against CD34, an endothelial cell marker. Two pathologists unaware of the patients’ long-term outcome counted microvessels in 10 microscopic fields from the most active areas of neovascularization. Results Between March 1988 and December 1996, 15 girls and 14 boys (median age 12.6 y, range 4.3-18.3) were identified. Seven patients had died of metastatic disease at a median of 3.4 years (range 0.8-7.4) after diagnosis; 22 were alive with no evidence of disease at a median follow-up of 6.8 years (range 2.7-11.4). There was no significant difference in the number of microvessels per field (pathologist 1, median 19 vs. 18.5; pathologist 2, median 15 vs. 10) between survivors or patients who died of metastatic disease. The correlation between the measurements of the two pathologists was excellent (correlation coefficient 0.87). Conclusions Intratumoral neovascularization determined at diagnosis does not correlate with long-term outcome in patients with nonmetastatic osteosarcoma. A prospective study is necessary to confirm these results.