Fig. 10

Linear GR calculation of a SRM in AS in a 73-year-old patient. a Contrast-enhanced CT of a renal mass (arrow) with a MTD of 1.7 cm (16.95 mm) at the beginning of AS and (b) 3 months later (arrow), showing a MTD of 2.4 cm (23.96 mm). Using the linear GR formula, the difference of MTD (2.4 cm − 1.7 cm = 0.7 cm) is divided by the time between the two CT scans (3 months), and the result (0.3 cm) is multiplied by 12, resulting in 2.6 cm. c Taking into account that the mass presented a GR of more than 0.5 cm/year, this mass should be considered as progressive, and AS should be discontinued. Following evaluation by a multidisciplinary committee, the patient underwent partial nephrectomy (arrow)