Preoperative interleukin-2 subcutaneous immunotherapy may prolong the survival time in advanced colorectal cancer patients.

It has been demonstrated that surgery may induce immunosuppression. This finding could influence the clinical course of surgically treated cancer patients. Moreover, preliminary experimental studies have shown that a preoperative injection of IL-2, whose importance in generating the antitumor immune response is well known, may neutralize surgery-induced immunosuppression. At present, however, it is still unknown whether preoperative IL-2-induced immune improvement in the postoperative period may influence the prognosis of surgically treated cancer patients. The present study was performed to evaluate the prognostic impact of IL-2 presurgical therapy in advanced colorectal cancer patients. The study included 50 colorectal cancer patients, Dukes' stage D, who were randomized to be treated with or without IL-2 preoperatively (18.10(6) IU/day subcutaneously for 3 consecutive days). After surgery, all patients underwent chemotherapy with 5-FU and folates until disease progression. Postoperative mean numbers of lymphocytes, T lymphocytes, natural killer cells and activated lymphocytes were significantly higher in IL-2-treated patients than in controls. Moreover, the percent of lymphocytic and/or eosinophilic tumor infiltration was significantly higher in IL-2 group than in controls. Finally, both survival curve and the percent of survival at 1 year were significantly greater in patients pretreated with IL-2 than in controls. This clinical trial demonstrates that preoperative IL-2-induced neutralization of postoperative lymphocytopenia is associated with a prolonged survival time in advanced colorectal cancer patients.