Neutrophil Number After Interferon-Alfa Treatment is an Independent Predictive Marker of Overall Survival in Metastatic Renal Cell Carcinoma

BackgroundThe purpose of this study was to assess the outcome in patients treated by immunotherapy using interferon-alpha (IFN-α) and to evaluate the significance of the neutrophil count after IFN-α immunotherapy as a predictive marker for metastatic renal cell carcinoma (RCC).Patients and MethodsWe identified 84 patients with metastatic RCC who underwent immunotherapy with IFN-α between 1998 and 2006. The predictive values of the neutrophil count before and after IFN-α treatment as well as other clinical and laboratory parameters were assessed retrospectively.ResultsOn univariate analysis, the significant correlation with overall survival (OS) was recognized in the Eastern Cooperative Oncology Group (ECOG) performance score (PS), lactate dehydrogenase (LDH) levels, corrected calcium levels, interval from diagnosis to treatment, and the ratio of neutrophil number before and after treatment with INF-α. Multivariate analysis showed that ECOG PS, corrected calcium levels, interval from diagnosis to treatment and neutrophil number after IFN-α treatment were independent factors for OS. Using the number of neutrophils after IFN-α treatment, subgroups were identified using the Memorial Sloan-Kettering Cancer Center (MSKCC) model. The 1-year survival rate was 93% vs. 63% in the intermediate-risk group and 34% vs. 8% in the poor-risk group. In the favorable-risk group, all patients had a good decrease in neutrophil number after treatment with IFN-α.ConclusionNeutrophil number after IFN-α treatment can be a good predictive marker for OS in metastatic RCC. By combining MSKCC score with neutrophil number after treatment with IFN-α, we can subdivide each group.