Introduction

pT3a disease is known to represent a poor prognostic factor in renal cell carcinoma (RCC) with an approximate four-fold increased risk for recurrence regardless of size when compared to pT1 disease. The impact of incidental pT3a upstaging in patients undergoing partial nephrectomy (PNx) for cT1 disease, however, is not well defined.

Methods

A retrospective chart review was completed at the University of Michigan and Moffitt Cancer Center to identify patients who underwent PNx between 1996-2015 for cT1 RCC with subsequent pathologic upstaging to pT3a disease. Patients with pT3a disease were compared to controls who underwent PNx for cT1 disease with final pathology confirming pT1 disease. Recurrence-free survival (RFS) and cancer-specific survival (CSS) were estimated using the Kaplan-Meier method.

Results

A total of 95 patients with pT3a upstaging were identified and compared to 1164 controls. Median follow up in our series was 38.2 (IQR 11.6-56.8) months. Following PNx, 20 (21%) patients with incidental pT3a upstaging suffered disease recurrence at a median of 28.7 months (IQR 10.3-43.5), consisting of 4 (4%) local recurrences and 17 (18%) distant metastases. In comparison, 8 (0.7%) controls suffered disease recurrence at a median of 46.6 months (IQR 17.7-74.2). In patients with pT3a disease, the 5- and 8-year RFS was 71% and 59%, compared to 88% and 78% in controls (p<0.0001). CSS was also significantly different between cohorts, with pT3a patients experiencing a 5- and 8-year CSS of 92% and 79%, compared to 99% and 98% in controls (p=0.001). Kaplan-Meijer curves are depicted in Figure 1. There were a total of 7 (7%) RCC related deaths, which occurred at a median of 28.5 months (IQR 9.3-54.3) in the pT3a cohort, while there were 5 (0.4%) RCC related deaths at a median of 96.5 months (IQR 56.9-96.9) in those with final pT1 disease.

Conclusions

The data presented here suggests that patients with cT1 disease and incidental pT3a upstaging following PNx experience a significantly reduced RFS and CSS compared to those with final pT1 disease, and thus may benefit from modified follow up protocols or early adjuvant therapies.

Funding

None