Prognostic Value of Vascular Invasion in Pediatric Osteosarcomas.

Metastatic status, histologic response, and quality of surgical resection are prognostic factors for osteosarcomas. Pathology reports sometimes describe peritumoral vascular invasion on surgical specimens after neoadjuvant chemotherapy but their prognostic significance as an independent parameter has never been reported. The aim of this study was to evaluate how the presence of this peritumoral vascular invasion could influence survival. We retrospectively analyzed histology, demographics, and outcomes of pediatric patients treated for osteosarcoma in our institutions between January 2007 and December 2012. A single pathologist analyzed the resection specimens after neoadjuvant chemotherapy. Fifty-one osteosarcomas were diagnosed over a 6-year period; nine had metastatic disease at diagnosis. Surgery was performed after neoadjuvant chemotherapy in all cases. We identified peritumoral vascular invasion in the surgical specimens in 15 cases. Two-year event-free survival (EFS) was 78 % (CI95%[64;93]) for patients without vascular invasion versus 48 % (CI95% [21;75]) in patients with vascular invasion, and 2-year overall survival (OS) was 94 % (CI95%[86;100]) for those without vascular invasion versus 79 % (CI95%[57;100]) for others. Multivariate analysis demonstrated correlation of metastatic status and presence of vascular invasion with survival. The histopathological description of peritumoral vascular invasion in surgical specimens of osteosarcoma after neoadjuvant chemotherapy can be considered a prognostic factor and could indicate modification of the postoperative therapeutic strategy.