THE reticuloendothelial system is the site of the body's hostal defensive reactions1 and has been implicated as a determinate factor in the course of cancer.2,3 If, in patients with cancer, depression of reticuloendothelial function occurred in association with surgery, an existing balance between a malignant tumor and the hostal reaction to this tumor might be altered. Additionally, if the system were depressed as a result of surgery, the ability of the patient to respond to bacterial challenge might be impaired.
The recent introduction of iodinated I 131 serum albumin microaggregated has provided a suitable test substance for study of the reticuloendothelial system in humans.4-6 When injected intravenously, the aggregates, which average 10mμ in diameter, are phagocytized by reticuloendothelial cells throughout the body. Their rate of disappearance is an index of the functional capacity of the reticuloendothelial system.7 Results on serial determinations are reproducible. Using this technique