Urinary collecting system invasion is no independent prognostic factor in renal cell carcinoma

To assess the specific impact of urinary collecting system (UCS) invasion on the long-term prognosis of patients with renal cell carcinoma (RCC).

We evaluated 1,678 patients with complete information about UCS invasion of their primary RCC who had undergone renal surgery between 1990 and 2005 in two high volume centers (MH Hannover and Marburg, Germany); the mean follow-up was 5.4 years.

Hundred and forty-nine (8.9%) patients demonstrated collecting system invasion. These patients incurred a significant increase in the likelihood of cancer-related death (HR 1.7, 95% CI: 1.4–2.0; P < 0.001), their median 5-year tumor-specific survival rate was 45% as opposed to 73% for patients without UCS invasion (P < 0.001). UCS invasion was significantly associated with tumor stage, grade, lymph node, and visceral metastasis at diagnosis but not with age, gender, histologic subtype, or body mass index. However, using multivariate analysis, UCS invasion disqualified as individual prognostic factor for RCC, neither for localized nor for advanced disease.

Facing the results of this large trial, we do not support the inclusion of UCS invasion into upcoming TNM staging systems. In contrast, future research should focus on novel molecular markers expressed by the tumor and/or specific immunological characteristics of patients with RCC which could improve prediction of RCC-associated prognosis.