Natural History and Management of Small Renal Masses
AbstractSmall renal masses (SRMs) are defined as cortical renal masses smaller than 4cm in diameter. The observed stage migration contributes to the increased detection of SRMs. Between 1983 and 2002 the incidence of renal tumors 2 to 4 cm in diameter rose from 1.0 to 3.3 cases per 100,000, representing a 244% increase.1 In the 1970s, approximately 10 percent of RCCs were discovered incidentally, compared to 60 percent in 1998.2Increased detection of asymptomatic SRMs cannot be fully explained by the more frequent use of abdominal imaging. Mindrup et al compared the frequency of occult RCC detected at autopsy between the periods of 1955-60 and 1991-2001 and noticed that despite the recent use of more frequent and sophisticated imaging techniques, there is no difference in the frequency of occult RCC (0.4%.and 0.5% respectively).3 In this series, the mean size of the occult RCC detected at autopsy was 65% smaller in the more recent group (1.65 cm vs 4.63 cm).3
Peak RCC incidence occurs in patients older than 65 years.4 Patients in this age group often have significant medical co morbidities which might impact on the choice of therapeutic options.
Management of SRMs must be individualized as several patient and tumor related factors will impact on our management strategy. The identification of such parameters necessitates revisiting the natural history of SRMs as well as the safety and efficacy of different available treatment modalities.