Objective: Interleukin-2 (IL-2) is a glycoprotein that influences the immunoendocrine network by several actions. This cytokine is commonly used in the patients with renal carcinoma, both as neo-adjuvant treatment prior to surgery and as adjuvant therapy. The aims of our study were to evaluate the IL-2 efficacy on postoperative survival rate in patients with metastatic renal carcinoma, to compare the efficacy of treatment with IL-2 alone with the results achieved by conventional systemic chemotherapy or association protocols IL-2-based and to examine the toxic effects of the IL-2-based therapeutic regimens in renal cell carcinoma (RCC).
Design: We enrolled 7 randomised trials concerning the IL-2-based treatments of RCC and performed meta-analytic processing by the Mantel-Haenszel-Peto method in order to achieve odds ratios and 95% confidence intervals of the examined treatments. We also considered 11 non-randomised trials, evaluating them in terms of survival rate through the endpoints available. In all trials taken into account, we finally examined the toxic effects as WHO grade, specifying study by study the main site involved.
Results and conclusions: Complete or partial response rates have been obtained in 6% to 30% of treated patients in all the trials considered. Our study revealed the need for careful screening as well as a continuous adjustment of doses when an immunotherapeutic protocol is employed in order to treat a metastatic renal carcinoma. Treatment with IL-2 alone achieves better results than systemic chemotherapy, even if the two types of treatment showed an almost overlapping medium- to long-term mortality rate. IL-2 plus lymphokine-activated killer cells accomplish only a partial response. The protocol with IL-2 plus IFN alpha displayed an interesting efficacy associated with a low toxicity even if the cumulative toxic effect of the two drugs should be carefully monitored. To date, the association of tumour-infiltrating lymphocytes, IL-2 and IFN alpha provided the best results in terms of survival and toxicity.