Delayed nephrectomy has comparable long-term overall survival to immediate nephrectomy for cT1a renal cell carcinoma: A population-based analysis.

Objectives: Early surgical resection remains the recommended treatment option for most small renal mass (≤4 cm). We examined the long-term overall survival (OS) of patients managed with delayed and immediate nephrectomy of cT1a renal cancer.
Patient and Methods: We utilized the National Cancer Database (2005-2010) to identify 14,677 patients (immediate nephrectomy: 14,050 patients vs. late nephrectomy: 627 patients) aged <70 years with Charlson Comorbidity Index 0 and cT1aN0M0 renal cell carcinoma. Immediate nephrectomy and late nephrectomy were defined as nephrectomy performed <30 days and >180 days from diagnosis, respectively. Inverse probability of treatment weighting-adjusted Kaplan-Meier curves and Cox proportional hazards regression analyses were used to compare OS of patients in the 2 treatment arms. Influence of patient age and Charlson Comorbidity Index on treatment effect was tested by interactions. Sensitivity analysis was performed to explore the outcome of delaying nephrectomy for >12 months.
Results: Median patient age was 55 years with a median follow-up of 82.5 months. Inverse probability of treatment weighting-adjusted Kaplan-Meier curves suggest no significant difference between treatment arms (immediate nephrectomy [<30 days] vs. delayed nephrectomy [>180 days]) (Hazard ratio 0.96; 95% confidence interval 0.73-1.26; P = 0.77). This outcome was consistent between all patients regardless of age (P = 0.48). Sensitivity analysis reports no difference in OS even if nephrectomy was delayed by >12 months (P = 0.60).
Conclusions: We report that delayed and immediate nephrectomy for cT1a renal cell carcinoma confers comparable long-term OS. These findings suggest that a period of observation of between 6 and 12 months is safe to allow identification of renal masses, which will benefit from surgical resection.
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