Interferon adjuvant to radical nephrectomy in Robson stages II and III renal cell carcinoma : a multicentric randomized study

PURPOSE: Because interferon gave promising results in the management of metastatic renal cell carcinoma in the 1980s, a multicentric randomized controlled trial was planned to compare adjuvant recombinant interferon alfa-2b (rIFNalpha2b) with observation after radical nephrectomy in patients with Robson stages II and III renal cell carcinoma. Overall and event-free survival were to be evaluated together with prognostic factors. PATIENTS AND METHODS: Overall and event-free survival curves for 247 patients (124 controls and 123 treated) were estimated by the Kaplan-Meier method and compared using the log-rank test. Cox's multiple regression models were adopted to perform a joint analysis of treatment and prognostic factors. RESULTS: The 5-year overall and event-free survival probabilities were 0.665 and 0.671, respectively, for controls and 0.660 and 0.567, respectively, for the treated group; the differences were not statistically significant (2P = .861 for overall and 2P = .107 for event-free survival with the log-rank test). Regarding prognostic factors, only grade, pT, and pN demonstrated a significant prognostic role. First-order interactions of treatment with pT and pN category were investigated; a significant interaction was found between pN and treatment. A harmful effect of rIFNalpha2b in the 97 treated pN0 patients and a protective effect in the 13 treated pN2/pN3 patients were statistically significant. CONCLUSION: Adjuvant rIFNalpha2b is not indicated after radical nephrectomy for renal cell carcinoma. The protective effect in the small group of pN2/pN3 patients requires further investigation.