In a systematic review of the literature, researchers found no significant difference between the growth rates of benign masses (0.3 cm/y) and those of malignant masses (0.35 cm/y) [82]. Furthermore, studies have shown that even masses without growth may be malignant [8,76,77,81]. In spite of this, growth rates are generally accepted as surrogates for aggressive behavior and metastatic potential in small renal masses [76,81]. Therefore, the guidelines recommend defining the growth rate of renal masses with serial imaging of the abdomen with CT or MRI within 6 months of the initiation of active surveillance for masses that are shown to be RCCs or oncocytic neoplasms and for those with indeterminate histology features [2,9]. Imaging should be performed at least annually thereafter with CT, MRI, or US. Imaging surveillance of the chest on a yearly basis (or more frequently depending on clinical behavior) is recommended only in those patients with RCC or tumors with oncocytic features [2,9]. Radiography Chest Metastatic progression occurs infrequently in patients with T1a renal masses on active surveillance [76,77,81]. Nevertheless, it has been reported that 20% to 30% of T1a tumors have potentially aggressive histologic features, thus requiring surveillance of the chest [9]. No studies have compared chest radiography and chest CT in the setting of active surveillance; however, chest radiography is the most commonly used method for surveillance [2,9]. This is in part because of concerns about potential false-positive findings with chest CT (ie, intrapulmonary lymph nodes and granulomas) that can lead to further unnecessary and potentially invasive investigations [9,12]. Radiography Abdomen There is no relevant literature regarding the use of abdominal radiographs in the surveillance of small localized renal masses, and this method is not recommended by the guidelines [2,9,11].
Post Treatment Follow up and Active Surveillance of Renal Cell Carcinoma. In a systematic review of the literature, researchers found no significant difference between the growth rates of benign masses (0.3 cm/y) and those of malignant masses (0.35 cm/y) [82]. Furthermore, studies have shown that even masses without growth may be malignant [8,76,77,81]. In spite of this, growth rates are generally accepted as surrogates for aggressive behavior and metastatic potential in small renal masses [76,81]. Therefore, the guidelines recommend defining the growth rate of renal masses with serial imaging of the abdomen with CT or MRI within 6 months of the initiation of active surveillance for masses that are shown to be RCCs or oncocytic neoplasms and for those with indeterminate histology features [2,9]. Imaging should be performed at least annually thereafter with CT, MRI, or US. Imaging surveillance of the chest on a yearly basis (or more frequently depending on clinical behavior) is recommended only in those patients with RCC or tumors with oncocytic features [2,9]. Radiography Chest Metastatic progression occurs infrequently in patients with T1a renal masses on active surveillance [76,77,81]. Nevertheless, it has been reported that 20% to 30% of T1a tumors have potentially aggressive histologic features, thus requiring surveillance of the chest [9]. No studies have compared chest radiography and chest CT in the setting of active surveillance; however, chest radiography is the most commonly used method for surveillance [2,9]. This is in part because of concerns about potential false-positive findings with chest CT (ie, intrapulmonary lymph nodes and granulomas) that can lead to further unnecessary and potentially invasive investigations [9,12]. Radiography Abdomen There is no relevant literature regarding the use of abdominal radiographs in the surveillance of small localized renal masses, and this method is not recommended by the guidelines [2,9,11].