Purpose: This study aimed to retrospectively evaluate the radiological features between rapid- and slow-growing renal cell carcinoma (RCC).
Materials and Methods: Twenty-five pathologically proven RCCs were reviewed with computed tomography (CT). Each tumor underwent at least 2 CT sessions. Growth rate was evaluated in terms of its maximal diameter and volume change with the serial CT scan. We reviewed 8 reports from 8 single-institution series in the world literature regarding growth rate of RCCs and determined mean growth rate. Slow- and rapid-growing RCCs were compared in relation to several radiological factors (tumor shape, initial size, initial volume, initial location, enhancement pattern, and cystic change). In addition, we evaluated differences in growth rate between asymptomatic and symptomatic RCCs.
Results: The mean diameter growth rate of RCC was determined as 0.49 cm/y (8 studies, 126 cases). There were 14 cases of rapid-growing RCCs (mean growth rate, 1.3 cm/y) and 11 cases of slow-growing RCCs (mean growth rate, 0.1 cm/y). The slow-growing tumors showed round shape, small initial size, small initial volume, and outer location of the kidney compared with the rapid-growing tumors. Sixteen patients (64%) were treated for incidental and 9 patients (36%) were treated for symptomatic RCCs. The asymptomatic RCCs grew at a slow rate both diametrically (P = 0.007) and volumetrically (P = 0.003).
Conclusions: Rapid- and slow-growing RCCs tend to show some different radiological features with respect to tumor shape, initial size, initial volume, and location. Radiological features may be helpful to predict growth rate.