New England Section of the American Urological Association

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Outcomes of Pathologic Upstaging of Clinical T1b and T2 Renal Cell Carcinoma
Melissa J. Huynh, MD, Douglas M. Dahl, MD, MPH, Edouard Nicaise, BA, Naren Nimmagadda, MD, MPH, Alice X. Yu, MD, Yichuan Hsieh, PhD, Michael L. Blute, MD, Adam S. Feldman, MD, MPH
Massachusetts General Hospital, Boston, MA

Background
Partial nephrectomy is the gold standard for the treatment of clinical T1a renal masses according to the American Urological Association guidelines, while the European Association of Urology extends their recommendations to also include T1b renal masses in order to maximize postoperative renal function and minimize metabolic and cardiovascular morbidity. In this study, we investigate the outcomes of clinical T1b and T2 renal cell carcinoma (RCC) treated by partial nephrectomy (PN) and radical nephrectomy (RN).
Materials & Methods
This was a retrospective single-institutional study of patients with clinical T1b and T2 renal masses undergoing either PN or RN from 2000-2017. Patients with metastatic disease on preoperative imaging were excluded from the study. The rates of pathologic upstaging and clinical outcomes including margin status, local recurrence, distant metastasis, and survival were compared between the 2 treatment groups.
Results
There were 462 clinical T1b and T2 renal masses in 454 unique patients. The median follow-up of the whole cohort was 35.6 months. Partial nephrectomy was performed in 149 patients, and 305 underwent radical nephrectomy (Table 1). Ten tumors (6.7%), all cT1b, were upstaged to pT3a in the PN group, while 122 (40.0%) were upstaged in the RN group (p<0.001). There was no statistically significant difference in the risk of positive margins or local recurrence, but there was an association of increased risk of metastasis in the RN group (p=0.04). For the 18 patients who experienced an RCC recurrence, the median time to recurrence was 13.6 months for PN and 11 months for RN (p=0.7703). There were more deaths in the radical nephrectomy group (17.4% vs. 6.0% for PN), although in the survival analysis, the difference in overall survival between the 2 groups did not reach statistical significance (log rank p=0.0601). In patients who had pathological upstaging, there was no associated increased risk of death from RCC or death from all causes between the partial and radical nephrectomy groups (p=0.198 and p=0.267, respectively).
Conclusions
There is a significant risk of pathologic upstaging in cT1b and larger tumors. However, when appropriately selected, partial nephrectomy for these tumors does not appear to compromise clinical outcomes and does not result in decreased survival compared to radical nephrectomy even in patients with pathological upstaging. When technically achievable, partial nephrectomy should be considered for these larger clinically localized renal masses.
Table 1. Clinical outcomes of clinical T1b and T2 renal cell carcinoma treated by partial nephrectomy and radical nephrectomy.

Partial NephrectomyRadical NephrectomyP-value
Patients (n)149305-
Tumors (n)152310-
Median follow-up (mos, [IQR])25.9 [18.8, 31.3]45.1 [37.2, 50.1]-
Clinical T1b (n, %)142 (46.7)162 (53.3)-
Clinical T2 (n, %)10 (6.3)148 (93.7)-
Tumor size (cm, median [IQR])5 [4.4, 5.5]6.8 [5.3, 9]<0.001
RCC histology
Clear cell106 (69.7)246 (79.4)0.023
Papillary31 (20.4)33 (10.6)0.004
Chromophobe15 (9.9)30 (9.7)0.948
Collecting duct0 (0)1 (0.3)0.483
Upstaged (%)10 (6.7)122 (40.0)<0.001
cT1b to pT3a1052<0.001
cT2 to pT3a0670.004
Positive margins (%)700.222
Local recurrence (%)10 (6.7)24 (7.8)0.653
Development of distant metastasis (%)10 (6.7)40 (13.1)0.04
RCC recurrence (local or distant) (%)18 (12.1)50 (16.4)0.222
Median time to relapse (mos, [IQR])13.6 [7.0, 54.9]11 [5.9, 40,2]0.7703
Deaths (%)9 (6.0)53 (17.4)0.001
Deaths from RCC (%)4 (2.7)27 (8.8)0.016
Deaths in upstaged patients (%)4 (40.0)29 (23.8)0.267
RCC deaths in upstaged patients (%)3 (30.0)18 (14.8)0.198


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