Interferon therapy of metastatic renal cell cancer.

There is no curative therapy for metastatic or recurrent renal cell carcinoma (RCC). Almost three-quarters of such patients die of their malignancy in 1 year and less than 5% of such patients are alive at 3 years. Few patients respond to hormonal therapy or chemotherapy, and when responses occur, they are usually brief and partial with little impact on survival. Interferon therapy in metastatic RCC has been associated with response rates of approximately 15-20%, and tumor regression has been demonstrated in patients treated with both partially purified and, more recently, recombinant interferon. Analysis of published trials shows no clear dose-response relationship; however, the highest therapeutic index appears associated with a daily dosage of 5-10 million units. The time to response is variable and may occasionally be prolonged; however, some patients have durations of response exceeding 12 months. Although nephrectomy may be associated with higher response rates, review of available data indicates that nephrectomy has frequently been an eligibility criteria, and indeed there are adequate descriptions of responses in patients that have not undergone this procedure. Patients with pulmonary metastases have the highest response rate. Recently, laboratory and clinical investigations of interferons and several chemotherapeutic agents, notably vinblastine, suggest synergy, but further data is needed to confirm these findings. The role of interferon therapy in improving survival is unknown. There is little doubt, however, that symptomatic patients who respond to interferon therapy may show improvement in their quality of life and prolongation of survival.