Staging renal cancer

The diagnosis of renal cell carcinoma (RCC) by means of imaging modalities include the identification of the lesion, its characterization, the staging and the follow-up. Staging is an important part of the diagnostic process since it has direct effect on the therapeutical decision. In the case of renal tumour, staging is based on the TNM (AJCC Cancer Staging system) which has replaced other staging classifications such as the Robson classification. Based on the TNM classification, two main types of renal tumours can be defined, the localized RCC (T1-T2) and the locally advanced RCC (T3-T4). In the case of T1 and T2 RCC, the most important parameter is tumour size: the cut point is 7 cm which separates T1 from T2 tumours. T1 tumours are further divided into T1a and T1b if less than 4 cm or between 4 and 7 cm, respectively. This further division has impact on type of surgery, i.e. partial versus radical nephrectomy. In the case of T3 and T4 RCC, different features should be carefully evaluated: these include the perirenal fat invasion, the direct infiltration of the ipsilateral adrenal gland, the infiltration of renal sinus fat, the vena cava and renal vein thrombosis, the urinary collecting system invasion and metastatic disease to local lymphonodes and other organs. CT still represents the method of choice for the staging of renal tumours since, also by using MPR and VR images, it gives all the information for the local and distant evaluation. MRI can support CT in complex cases