Blood irradiation for intraoperative autotransfusion in cancer surgery: demonstration of efficient elimination of contaminating tumor cells

BACKGROUND: Intraoperative blood salvage is contraindicated in cancer surge ry because of contaminating tumor cells and the risk of systemic disseminat ion. On the basis of the radiosensitivity of cancer cells, irradiation of s alvaged blood with 50 Gy is proposed as a way to allow return of salvaged b lood. STUDY DESIGN AND METHODS: Elimination of tumor cells by blood irradiation w as studied in vitro with cells from 10 cell lines and from 14 tumor prepara tions after their addition to red cells in high numbers, or with blood shed during cancer surgery. Before and after gamma radiation, tumor cells were isolated by density gradient centrifugation and tested for their proliferat ive capacity in a cell colony assay. DNA metabolism was analyzed by incorpo ration of 5' bromodesoxyuridine. RESULTS: Survival curves of cells from various tumors confirmed D-0 (the do se required to reduce the fraction of surviving cells to 37 percent of the original value) values in the range of 1.2 to 2.2 Gy. After irradiation of tumor cell-contaminated blood with 50 Gy, no cell colony formation was obse rved; which indicates a reduction rate exceeding 10 log. Irradiated cancer cells showed viability, but no residual DNA metabolism. CONCLUSION: The level of inactivation by a 50-Gy dose far exceeds that need ed to inactivate the number of proliferating tumor cells observed or expect ed in wound blood. These results provide the experimental basis for the cli nical application of blood irradiation for intraoperative blood salvage in cancer surgery.