Histologic Subtype Needs to Be Considered After Partial Nephrectomy in Patients with Pathologic T1a Renal Cell Carcinoma: Papillary Vs. Clear Cell Renal Cell Carcinoma

Purpose: We compared the oncological outcomes of papillary renal cell carcinoma (pRCC) with clear cell renal cell carcinoma (ccRCC) after partial nephrectomy (PN) in patients with pathologic T1a RCC.

Methods: After excluding patients with synchronous multiple renal tumors, familial RCC, and pathologic stage T1b or above, 759 patients with ccRCC and 84 patients with pRCC were included. We assessed the impact of histologic subtypes on oncologic outcomes after PN in patients with pathologic T1a RCC (median follow-up duration, 67 months).

Results: There was no difference in patient and tumor characteristics between the 2 groups, except Fuhrman grade (p = 0.006). Kaplan-Meier analysis identified 5-year recurrence-free survival of 98.7 and 95.6% in patients with ccRCC and pRCC, respectively. However, 10-year recurrence-free survival in patients with ccRCC and pRCC was 96.1 and 73.0%, respectively (p < 0.001). Recurrence ≥5 years post surgery was more common in patients with pRCC compared with those with ccRCC (0.3 vs. 4.8%; p < 0.001). In multivariate analysis, pRCC [hazard ratio (HR) 5.309; p = 0.001] was a significant risk factor for recurrence after PN in patients with pathologic T1a RCC, in addition to larger tumor size (HR 1.861; p = 0.038) and Fuhrman grade ≥3 (HR 5.176; p = 0.003).

Conclusions: In patients with pathologic T1a RCC, recurrence after PN occurred more commonly in pRCC compared with ccRCC. As over half of the recurrence cases in patients with pRCC occurred ≥5 years post surgery, a longer follow-up time is required, even for those with pathologic stage T1a disease.