Posters— Diagnostic Imaging/Pathology

HOST IMMUNE RESPONSE IN OSTEOSARCOMA

Casanova J, Reith JD, Berrey BH, Enneking WF, Scarborough MT (University of Florida, Gainesville, FL, 32610)

Background: Few previous studies document the role and significance of the host immune response in high-grade osteosarcoma. This retrospective analysis examines the nature of the inflammatory response found in and around osteosarcomas and the relationship to disease free and overall survival.

Patients and Methods: All patients had stage IIB osteosarcomas about the knee (distal femur, proximal tibia). Group A included 20 patients who were biopsied and treated with neoadjuvant chemotherapy and surgical resection. Group B included 73 patients who underwent surgical resection of their tumor and were treated with postoperative chemotherapy. All histologic slides examined included tumor and the adjacent reactive zone. Each case was evaluated with antibodies to CD3, CD4, CD8, CD20, and TIA-1 using standard avidin-biotin-complex methods. The number of CD3, CD8, and CD20 positive inflammatory cells was further quantified by histomorphometry.

Results:

Conclusions: An increased number of inflammatory reaction around osteosarcomas appears to be related to better survival, particularly when patients are given neoadjuvant chemotherapy. Presence of high numbers of T-cell tumor infiltrating lymphocytes (CD3, CD4, CD8 positive cells) correlates with improved survival. B cells and natural killer cells (CD20 and TIA-1 positive, respectively) appear to play a less significant role in the immune response.