Adult Sporadic Multifocal Renal Cell Carcinoma: Helical CT and Pathology Correlations in a Recent and Consecutive Set of Patients Assessed According to a Multidisciplinary Approach

Background and Aims:  To assess helical CT sensitivity in detecting preoperatively Multifocal Renal Cell carcinoma (MFRCC) and clinical occult multifocality in a contemporary and consecutive set of patients according to a multidisciplinary approach. 

Methods: The renal masses were assessed preoperatively by volumetric multislice helical CT with the objective to detect multifocality. Renal cells carcinoma (RCCs) were classified as unifocal (UF) or multifocal (MF). MFRCCs were selected in 2 groups including CT detected (CT+) and CT undetected (CT-). RCCs were classified in UF and MF. MFRCCs were selected in 2 groups including CT+ and CT-. CT and pathologic findings of MFRCCs were correlated and CT sensitivity was assessed. Statistical methods were performed in order  to compare the CT sensitivity with the overall mean sensitivity calculated from the reported literature, to assess statistical inference between UF and MF - RCCs; and to detect statistical significance between CT(+) and CT(-) MFRCCs .

Results: Over a period of 24 months, 116 kidney units (KU) of 111 patients were surgically treated for RCC. Multifocality was assessed in 13/116 KU of 12 patients (10.8%). Helical CT detected preoperative multifocality in 8/111 patients (7.2%) and preoperative occult multifocality was assessed in 4 (3.6%), as well. Helical CT sensitivity difference between our (66.7%) and the reported literature experience (22.9%) was significant (p <0.0001). Significant predictors for multifocality were tumor size (p = 0.007), laterality (p = 0.002), pT (p = 0.008) and surgery (p = 0.0002). Primary tumor size (p = 0.05) and satellite tumor size (p = 0.01) were significantly correlated to CT-undetected (CT-) multifocal tumors. 

Conclusions: In our experience, helical CT was effective in improving preoperative detection of sporadic primary MRCC as well as in lowering clinical occult multifocality. Clinical predictors of multifocality including bilaterality and primary tumor size as well as technical and methodological improvements in performing Helical CT will improve its sensibility in detecting renal masses less than 0.5 cm. CT preoperative detection of clinical multifocality may help in planning effective preoperative surgical treatment as well as lowering local recurrence after nephron sparing surgery.