Management Of The Small Renal Mass
January 11, 2018
Small renal masses are defined as stage T1a lesions (less than 4cm), but certainly lesions less than 2cm fall into this definition. There is a 126% increase in the detection of renal cell cancers since 1950, due to increased imaging and incidental detection of renal masses. It is suggested that the mean tumor growth rate of a grade 2 renal cancer is 0.28cm/yr, compared to 0.93cm/yr for a grade 3 tumor. The adequacy of a renal biopsy has been demonstrated to by over 96% in numerous studies, with sufficient tissue acquired when an 18 gauge core needle is used. Most often, the core sample is sufficient to provide a histology and tumor grade. These improved biopsy outcomes are the result of improved imaging and the use of a core needle as opposed to needle aspirations, which were historically used. Some argue that a needle biopsy will not change treatment, but 4 studies show that treatment was changed in 30-60% of patients who had a biopsy.
Surveillance is based upon using a biopsy to determine histology and grade. Over 90% of renal masses are