The Modern Basis for Nephron-Sparing Surgery in Patients with Renal Cancer: Biologic Heterogeneity, the Significance of Tumor Biopsy, and the Changing Roles of Partial Nephrectomy and Tumor Ablation

Although complete surgical removal is the primary objective in the treatment of small renal masses (SRMs), technological advances have led to greater use of nephron-sparing surgery and other minimally invasive therapies. With increasing recognition that the malignant potential of SRMs is heterogeneous, ranging from benign tumors (15–20%) to aggressive kidney cancers (20%), enthusiasm for more conservative management strategies in the elderly and infirmed, such as active surveillance (AS) and ablative therapy (AT), has grown considerably. The role of renal mass biopsy (RMB) to help guide individualized therapy is also changing. However, significant intratumoral heterogeneity in clear-cell renal cell carcinoma (RCC) raises profound questions concerning the genetic landscape of cancer and how tumor heterogeneity may affect, and possibly confound, targeted diagnostic and therapeutic interventions. Herein we review the modern basis for nephron preservation in patients with RCC, identify challenges posed by biologic heterogeneity, highlight the evolving role of RMB, and discuss the roles of partial nephrectomy and tumor ablation.