Hilar location is an independent prognostic factor for recurrence in T1 renal cell carcinoma after nephrectomy.

Purpose: We investigated the prognostic significance of tumor location at the renal hilum near the sinus structure on the recurrence in T1 renal cell carcinoma (RCC).

Methods: A total of 1,818 T1 RCC patients who underwent radical (RN) or partial nephrectomy (PN) from 1997 to 2011 were retrospectively reviewed. A hilar tumor was defined as a tumor abutting the main renal artery and/or vein or its segmental branches, without invasion. We compared the recurrence-free survival (RFS) rates between hilar and nonhilar T1 RCC and analyzed predictors of RFS after nephrectomy.

Results: Patients with hilar tumors showed a poorer 5-year RFS compared with nonhilar tumors both in T1a (89.7 vs. 98.5 %, p < 0.001) and T1b (81.6 vs. 95.1 %, p < 0.001) RCCs. Among patients who underwent RN and PN, hilar tumors were associated with lower 5-year RFS (87.6 vs. 97.2 % for RN, 78.1 vs. 98.2 % for PN, both p < 0.001). In T1a hilar tumor, PN was associated with poorer 5-year RFS than RN (79.5 vs. 93.0 %, p < 0.001). In multivariate analysis, a hilar location remained as an independent predictor of recurrence in both T1a and T1b tumors (both p = 0.001).

Conclusions: Hilar tumors show a higher recurrence rate than nonhilar counterparts in T1 RCC. In T1a hilar tumors, PN demonstrated poorer RFS than RN. Potential intrinsic renal anatomical or lymphovascular structural differences as well as differences in cancer characteristics need further investigations.