Purpose: A relationship between the urinary albumin excretion rate (UAE) and different types of tumors has been previously described but little is known about UAE and renal cell cancer (RCC). We evaluated the prognostic significance of UAE and its correlation with tumor clinicopathological findings in patients with RCC treated with recombinant interleukin-2 (rIL-2) and recombinant interferon-alpha (rIFN-alpha). Because rIL-2 and rIFN-alpha increase glomerular permeability, we also determined whether the first immunotherapy cycle induced a significant increase in UAE and whether it was related to tumor parameters.
Materials and methods: A total of 51 consecutive patients with RCC were enrolled. Inclusion criteria were patient age at diagnosis younger than 70 years and serum creatinine less than 1.8 mg/dl. Patients with central nervous system metastases and diabetes mellitus were excluded. Nephrectomy was followed by systemic treatment with 1-month cycles of low dose rIL-2 and rIFN-alpha, which were repeated every 4 months, UAE was determined before and after the first treatment cycle.
Results: Univariate analysis showed that pre-cycle and post-cycle UAE greater than 30 mg/24 hours significantly influenced survival (p = 0.006 and 0.007, respectively). A multivariate model adjusted for age at onset, performance status, post-cycle UAE, tumor stage and grade, and metastases showed that pre-cycle UAE greater than 30 mg/24 hours had an independent prognostic role (p = 0.011). The first treatment cycle increased UAE 81.8% vs baseline (p = 0.002). The post-cycle vs pre-cycle increase was significant in patients with stages III-IV (p = 0.003) and grades 3-4 (p = 0.028) tumors. Pre-cycle and post-cycle UAE were significantly higher in stages III-IV than in stages I-II cases (p = 0.030 and 0.007, respectively).
Conclusions: UAE is an independent prognostic factor that is related to disease stage in patients with RCC.