Ten-year survival results in metastatic renal cell cancer patients treated with monoimmunotherapy with subcutaneous low-dose interleukin-2.

ABSTRACT

After more than ten years of clinical investigations, IL-2 immunotherapy appears to constitute the most effective treatment metastatic renal cell carcinoma (RCC),at least in terms of survival time. Moreover, it has been shown that comparable results may be achieved with different schedules of treatment, including intravenous high-dose or subcutaneous (SC) low-dose IL-2. Finally, it has been demonstrated that the association with interferon-alpha does not increase the efficacy of IL-2. Therefore, SC low-dose IL-2 alone may be considered as an adequate therapy for metastatic RCC. In fact, our previous studies with SC low-dose IL-2 alone have shown a 5-year survival time similar to that described with higher and more toxic doses of IL-2. This study was performed to analyze the 10-year survival results with SC low-dose IL-2 in metastatic RCC The study included 44 consecutive metastatic RCC patients, with a minimum follow-up of 120 months. One comlete immunotherapeutic cycle consisted of IL-2 at 3 million IU twice/day SC, 5 days/week for 6 consecutive weeks. In non-progressing patients, a second cycle was planned after a 21-day rest period. Complete response (CR) was achieved in only 2 out of 44 (4%) patients, while partial response (PR) was obtained in 8 out of /44 (18%) patients. Therefore, the response rate (CR + PR) was 10 out of 44 (22%), with a median response duration of 12 months. Stable disease (SD) occurred in 21 out of 44 (48%) patients,whereas the remaining 13 out of 44 (30%) patients had a progressive disease (PD). A 10-year survival was achieved in 2 out of 44 (5%) and the percent of survival at 10 years was significantly higher in patients with response or SD than in those with PD. This study confirms at 10 years the results previously referred to by other authors and by ourselves, in showing that the efficacy of IL-2 immunotherapy in terms of control of cancer growth is associated with a clear prolongation of the overall survival time in metastatic RCC.