Interleukin-2 in Renal Cell Carcinoma: A Has-Been or a Still-Viable Option?

Modulation of the immune response plays an important role in the natural history of renal cell carcinoma. Spontaneous regression of metastases has been well documented in a small percentage of patients after they undergo de-bulking nephrectomy without any additional systemic intervention. The only logical explanation for these observations is "resetting" of the balance between tumor and the host immune system that, having been overwhelmed by the tumor burden, is able to function better after tumor de-bulking. Attempts to modulate the activity of the immune system "on demand" have included the use of vaccines, cytokines/lymphokines, adoptive cell transfer, monoclonal antibodies and most recently manipulation of immune checkpoint inhibitors. Here we review the data for infusional interleukin-2 in the management of advanced renal cell carcinoma and its role in current clinical practice.