Effects of long-term combination chemotherapy on the reticuloendothelial system

The phagocytic and metabolic functions of the reticuloendothelial system (RES) were studied in 20 postoperative cancer patients undergoing long-term combination chemotherapy. Each course included vincristine, methyl-CCNU (day 1) and 5-fluorouracil (days 1-5) every sixth week. The RES-test was performed prior to each course, using 125I-labeled microaggregated human serum albumin. Total leukocytes, mononuclear cells and platelets were monitored before, during and after each treatment. A significant, initial impairment of the catabolic function of the RES was found (2P = 0.006). A similar, nonsignificant trend was observed in the phagocytic function. The normalization may mirror the large metabolic capacity of the RES. This is further demonstrated by the fact that splenectomized (N = 9) and nonsplenectomized patients did not differ. A significant decrease was also found in total leukocytes and mononuclear cells (2P less than 0.001). Combination chemotherapy induced a similar myelosuppression in both groups, but did not further reduce the mobile RES in asplenic individuals.