Prognostic heterogeneity in T3aN0M0 renal cell carcinoma according to the site of invasion.

PURPOSE: We investigated the influence of the site of invasion on recurrence and survival in patients with pT3aN0M0 renal cell carcinoma (RCC).

MATERIALS AND METHODS: We reviewed the data of 266 patients with pT3aN0M0 RCC who underwent nephrectomy and divided them into the following 5 groups according to the site of invasion: perinephric invasion (PNI), sinus fat invasion (SFI), PNI and SFI without renal vein invasion (RVI) (i.e., PNI+SFI), RVI, and RVI with PNI and/or SFI (RVI+PNI±SFI). Subgroup analysis was performed to verify the differences in prognosis according to the extent of renal vein invasion using Cox regression models.

RESULTS: A total of 111 patients (41.7%) experienced recurrence and 59 patients (22.2%) died of disease during follow-up (median = 58.1mo; interquartile range: 37.2-86.5). Patients with RVI showed significantly poorer outcomes than those with fat invasion in terms of 5-year recurrence-free survival (34.3% vs. 62.2%, P<0.001) and cancer-specific survival (62.8% vs. 84.1%; P<0.001). In multivariate analysis, RVI was an independent prognostic factor for recurrence and survival. In 94 patients with RVI, the 5-year recurrence-free survival rates were 50.0%, 33.9%, and 8.9% for the thrombus-only, the vascular wall invasion with negative surgical margin, and the vascular wall invasion with positive surgical margin groups, respectively (P<0.001), and the cancer-specific survival rates were 82.3%, 56.6%, and 20.0%, respectively (P<0.001). Wall invasion was the only independent prognostic factor for cancer-specific survival in these patients.

CONCLUSIONS: Patients with pT3aN0M0 RCC with RVI have a significantly poorer prognosis than those with fat invasion. The prognosis differs according to the extent of RVI. Wall invasion should be considered a negative prognostic indicator in patients with T3a RCC.