High-dose interleukin-2 for the treatment of metastatic renal cell carcinoma - A retrospective analysis of response and survival in patients treated in the Surgery Branch at the National Cancer Institute between 1986 and 2006

BACKGROUND. The treatment of metastatic renal cell carcinoma (RCC) with high-dose interleukin-2 (HD IL-2) has resulted in durable tumor regression in a minority of patients. The current study presents the authors' 20-year experience administering this immunotherapeutic agent. METHODS. Patients with metastatic RCC (n = 259) were treated with HD IL-2 alone from January 13, 1986 through December 31, 2006 at the Surgery Branch of the National Cancer Institute. Potential predictive factors for response and survival, both pretreatment and treatment-related, were first subjected to univariate analysis and then to multivariate logistic regression or a Cox proportional hazards model. Finally, the authors investigated Memorial Sloan-Kettering Cancer Center (MSKCC) prognostic factors for survival to assess their predictive value in the patient population in the current study. RESULTS. A total of 23 patients experienced a complete response and 30 patients achieved a partial response, for an overall objective response rate of 20%. All partial responders had developed disease recurrence at the time of last follow-up, but only 4 complete responders had experienced disease recurrence by that time. Despite toxicities, only 2 patients developed treatment-related mortalities over this same time period. A higher baseline weight (P = .05) and MSKCC prognostic factors (P = .02) were found to be the variables most associated with response. For survival >4 years and overall survival, several pretreatment and treatmentrelated factors maintained significance, but none more so than response (P < .0001). CONCLUSIONS. HD IL-2 can induce complete tumor regression in a small number of patients, and many patients have experienced extended disease-free intervals. Given its relative safety, HD IL-2 should still be considered a first-line therapy in patients with metastatic RCC who have an overall good performance status.