Survival in renal cell carcinoma-a randomized evaluation of tamoxifen vs interleukin 2, α-interferon (leucocyte) and tamoxifen

Abstract

Metastatic renal cell carcinoma (RCC) has a poor prognosis. Conventional treatment strategies, including chemotherapy and hormonal therapy, have limited value. Although encouraging results have been achieved in terms of objective response using immunological manipulations, no conclusive studies yet exist with a controlled comparative evaluation of survival. Therefore, the present study was undertaken, which compared one of the present (and presumed best) treatments, interleukin 2/interferon-alpha (IL-2/IFN-alpha) and tamoxifen, with a control arm of tamoxifen only. Tamoxifen has been shown to potentiate in vivo anti-tumour activity of IL-2, and because of its non-toxic behaviour it was included in both groups. The study was open, randomized and included seven institutions in Sweden. The patients were stratified according to the different centres involved. An interim analysis was planned when a minimum of 100 patients were evaluable. The 128 patients finally included had a histologically documented metastatic RCC, with a life expectancy of more than 3 months, a performance status WHO 0-2 and no prior chemo- or immunotherapy. Informed consent was obtained from each patient. The patients randomized to the control arm (n = 63) received only tamoxifen 40 mg p.o. daily for at least 1 year or until progression. The patients (n = 65) randomized to biotherapy received subcutaneous recombinant IL-2, leucocyte IFN-alpha in a treatment cycle of 42 days, as well as tamoxifen p.o. In the absence of undue toxicity or disease progression, these patients received one additional treatment cycle of 42 days followed by maintenance treatment, consisting of 5 days therapy every 4 weeks, for 1 year, or until proven progression. Only two patients in the tamoxifen-only group received immunotherapy when the disease progressed, but without any beneficial effect. All patients received appropriate local treatment when indicated. The interim analysis demonstrated no survival advantage for either group, and therefore further inclusion of patients was stopped. The median follow-up was 11 months (range 0.4-48 months). The final survival analysis showed no significant differences between the two treatment arms in so far as comparison from the day of diagnosis of primary disease, from the day of first evidence of metastatic spread, or from the onset of treatment. This was valid both when the evaluation was performed with regard to intention to treat and when the analysis was directed only to patients that managed at least one treatment cycle (42 days) of IL-2/IFN-alpha. The adverse effects were more pronounced in the IL-2/IFN-alpha group. Although the number of patients is limited, the results raise doubt concerning immunotherapy with IL-2 and IFN-alpha as a routine treatment in the management of advanced RCC. The difference in cost of drugs and health care (drug costs per patient: IL-2/IFN-alpha $27000 vs tamoxifen $360) as well as adverse effects caused by IL-2/IFN-alpha are also factors of importance. The study emphasizes the need for more effort to find the 'optimal schedule' of immunotherapy, as well as the need for randomized controlled studies before approval of a new treatment in the routine setting.