Objectives: To analyze blood shed from the surgical field during oncologic surgery for tumor cells and to assess functional characteristics of these cells.
Design and patients: Series of 61 patients with cancer who underwent surgery for an abdominal, orthopedic, urological, gynecological, or head and neck malignant tumor, and blinded comparison with 15 patients with benign diseases undergoing surgery.
Setting: A 500-bed tumor center and a tertiary care hospital.
Main outcome measures: Tumor cells were isolated from intraoperatively salvaged and washed blood by density gradient centrifugation. They were identified in cytospin specimens by their content of cytokeratins and nucleolar organizer regions with a sensitivity of 10 cells in 500 mL of blood. Clonogenicity was tested in a cell colony assay; invasiveness, in Boyden chambers; and tumorigenicity, in nude mice.
Results: In 57 of 61 patients, tumor cells were detected in the blood shed during oncologic surgery. They demonstrated proliferation capacity, invasiveness, and tumorigenicity. The total number of tumor cells identified ranged from 1 x 10(1) to 7 x 10(6), with no close correlation to the amount of blood loss. Circulating tumor cells were demonstrated in only 26% of these patients and in small numbers.
Conclusions: Malignant cells identified regularly in the blood shed during tumor surgery and different from circulating tumor cells are of concern, since at the surgical site they may cause local tumor recurrence, or in the salvaged blood they may cause hematogenic metastasis after retransfusion. Therefore, the contraindication of intraoperative autotransfusion in tumor surgery is strongly supported, and a review of surgical procedures and adjuvant therapy may be indicated, as the passage of the identified cells to the shed blood is yet unknown.