There is a lack of literature that have directly compared the accuracy of chest CT with chest radiography for detecting pulmonary metastases in the initial staging of RCC. However, limited data have demonstrated that CT is more sensitive than radiography for the detection of pulmonary metastases from RCC [49]. Hence, CT chest with IV contrast is recommended by the current NCCN guidelines [13]. Apart from identifying pulmonary metastases, chest CT has a high sensitivity for the detection of hilar and mediastinal nodal metastases from RCC [50]. Although it is generally accepted that CT has a high sensitivity for detecting pulmonary nodules, it should be noted that presence of small subcentimeter pulmonary nodules does not equate to pulmonary metastases. Most patients with small T1a RCCs are unlikely to have pulmonary metastases. Prior studies have reported that the risk of metastases is highly correlated with size of the tumor and is virtually nonexistent in tumors <2 cm in size, occurs <1% in tumors of 2 to 3 cm, and occurs approximately 1% to 2% for lesions 3 to 4 cm [51-53]. Hence, the presence of small subcentimeter pulmonary nodules in T1a RCCs is often likely to be a false-positive finding (ie, intrapulmonary lymph nodes and granulomas) but can lead to further unnecessary and potentially invasive investigations. CT Head Most patients with metastases to the central nervous system are symptomatic. Thus, current guidelines from the EAU and NCCN do not support routine imaging of the brain to search for metastases in asymptomatic patients in the initial staging of RCC. Brain imaging should be performed only in cases with suggestive signs or symptoms [5,13]. Recent studies indicate that up to 4% of patients with advanced, metastatic RCC may harbor asymptomatic brain metastasis [56,57]. Hence, routine brain imaging with IV contrast may be considered in patients with advanced, metastatic RCC, even if they are asymptomatic [56,57].
Staging of Renal Cell Carcinoma. There is a lack of literature that have directly compared the accuracy of chest CT with chest radiography for detecting pulmonary metastases in the initial staging of RCC. However, limited data have demonstrated that CT is more sensitive than radiography for the detection of pulmonary metastases from RCC [49]. Hence, CT chest with IV contrast is recommended by the current NCCN guidelines [13]. Apart from identifying pulmonary metastases, chest CT has a high sensitivity for the detection of hilar and mediastinal nodal metastases from RCC [50]. Although it is generally accepted that CT has a high sensitivity for detecting pulmonary nodules, it should be noted that presence of small subcentimeter pulmonary nodules does not equate to pulmonary metastases. Most patients with small T1a RCCs are unlikely to have pulmonary metastases. Prior studies have reported that the risk of metastases is highly correlated with size of the tumor and is virtually nonexistent in tumors <2 cm in size, occurs <1% in tumors of 2 to 3 cm, and occurs approximately 1% to 2% for lesions 3 to 4 cm [51-53]. Hence, the presence of small subcentimeter pulmonary nodules in T1a RCCs is often likely to be a false-positive finding (ie, intrapulmonary lymph nodes and granulomas) but can lead to further unnecessary and potentially invasive investigations. CT Head Most patients with metastases to the central nervous system are symptomatic. Thus, current guidelines from the EAU and NCCN do not support routine imaging of the brain to search for metastases in asymptomatic patients in the initial staging of RCC. Brain imaging should be performed only in cases with suggestive signs or symptoms [5,13]. Recent studies indicate that up to 4% of patients with advanced, metastatic RCC may harbor asymptomatic brain metastasis [56,57]. Hence, routine brain imaging with IV contrast may be considered in patients with advanced, metastatic RCC, even if they are asymptomatic [56,57].