Small renal masses: surgery or surveillance

The incidence of kidney cancer has been rising over the past two decades, especially in cases in which the disease is localized and small in size (<4 cm). This rise is mainly due to the widespread use of routine abdominal imaging such as ultrasonography, computed tomography, and magnetic resonance imaging. Early detection was initially heralded as an opportunity to cure an otherwise lethal disease. However, despite increasing rates of renal surgery in parallel to this trend, mortality rates from renal cell carcinoma have remained relatively unchanged. Moreover, data suggest that a substantial proportion of small renal masses are benign. As a result, the management of small renal masses has continued to evolve along two basic themes: it has become less radical and less invasive. These shifts are in part a reflection of an improved understanding that the biology of incidentally discovered renal cell carcinoma may be more indolent than previously thought. However, not all small renal masses are indolent, and de novo metastatic disease can develop at the initial presentation. Therefore, it is with this background of clinical uncertainty and biological heterogeneity that clinicians must interpret the benefits and disadvantages of various clinical approaches to small renal masses.