PATHOLOGICAL STAGE DOES NOT ALTER THE PROGNOSIS FOR RENAL LESIONS DETERMINED TO BE STAGE T1 BY COMPUTERIZED TOMOGRAPHY

Abstract

Pathological stage has been the most widely used prognosticator for evaluating surgically managed cases of renal cell carcinoma. Minimally invasive surgical approaches are being increasingly used to treat small masses for which traditionally pathological information is lacking (morcellation) or absent (radio frequency ablation or cryoablation). Preoperative cross-sectional imaging by computerized tomography (CT) or magnetic resonance imaging has been used to stage renal tumors clinically but it can lead to variances with traditional pathological staging systems, particularly with respect to microscopic invasion beyond the renal capsule. In this study we assessed whether radiographically staged clinical T1 lesions that were pathological T1 behave differently than those that were clinical stage T1 and up staged to pT3a. The records of 296 patients who underwent surgical treatment for renal cell carcinoma at The Johns Hopkins Hospital between 1990 and 1999 were retrospectively reviewed. All patients had undergone preoperative CT or magnetic resonance imaging, which was used to assign a clinical stage and size (largest diameter) to each tumor in accordance with the 1997 TNM staging system. Following surgical resection pathological stage, size and tumor grade were determined. Only the 186 patients with clinical T1 tumors were included in this analysis. Of the 186 patients who were clinically found to have T1 lesions 125 (67%) had pathological T1 and 57 (31%) had pathological T3a lesions. All surgical margins and lymph nodes were negative at surgical resection. Mean tumor size ± SD was 3.9 ± 1.5 cm for pT1 lesions and 3.8 ± 1.5 cm for pT3a lesions. When comparing these pathological groups using Kaplan-Meier analysis, 5-year recurrence-free survival was not statistically different in patients with pT1 and pT3a lesions (90.6 and 97.5%, respectively). Patients in whom the initial classification of T1 renal cell carcinoma by CT was up graded to T3a on pathological analysis (invasion of fat within Gerota's fascia) showed the same recurrence-free survival rate as patients with pathologically confirmed T1 lesions. Thus, smaller tumors (less than 7 cm) that are up graded to T3a based on capsule invasion behave much like T1 tumors and exact pathological T staging does not appear to impact overall survival.