Intrasplenic immunostimulation in malignancies fact or fiction? Present and future

The clinical application of intrasplenic immunostimulation with IL-2 in a group of patients suffering from metastatic renal carcinoma, melanoma, recurrent rectal carcinoma, lung carcinoma and gastric carcinoma are discussed in terms of clinical applicability, effectiveness and survival.

From May 1996 to February 1998, 45 patients with advanced malignancies were admitted to Athens Medical Center for intrasplenic immunostimulation. Transplenic immunostimulation was carried out via a subcutaneously implanted port. The injected therapy included IL-2 (Proleukin) 1 ml 18 x 10(6) suspended in 1.5 ml of lipiodol and 0.5 ml of urografin. In conjunction gamma-INF (Immukin) 0.5 ml 100 mcg, was administered.

Patients included in this study have completed their treatment, or are still undergoing maintenance treatment. The duration of the CR was between 11 and 16 months, and for PR was between 10-14 months. For melanoma patients (n = 9), 3 patients with PD died 9, 10 and 12 months after initial treatment began. The remaining patients (n = 6) are alive with a mean survival rate of 16 months. Of those patients, 4 have been classified as complete responders, being completely free of disease at this time. The number of CR for patients with lung, renal and recurrent rectal cancer was achieved as a result of the continuing maintenance treatment. Twenty-two patients remain alive and 23 patients have died. From those alive (n = 22), 10 patients are complete responders and free of disease, 10 are partial responders with controlled disease and 2 remain with standard disease. For those surviving patients with lung cancer, the mean survival time is 14 months. Patients with recurrent rectal cancer and renal cancer were shown to have a mean survival time of 15 and 13 months, respectively.

The safety, effectiveness and feasibility of long-lasting administration of high dosages of IL-2 are documented from the data of this study. Intrasplenic immunostimulation utilizing lipiodol-urografin emulsion as a carrier, offers new possibilities for the safe administration of long lasting high dosages of IL-2 and gamma-INF. Further studies are warranted, to further elucidate the results of this phenomenon.