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 = 58.1 mo; 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.