Clinical Versus Pathologic Staging of Renal Tumors: Role of Multi-Detector CT Urography

Introduction: Our ability to diagnose renal cell carcinoma (RCC) has increased in the past 30 years as a result of the extensive application of imaging techniques, such as ultrasonography, computed tomography, and magnetic resonance imaging. Multi-detector computed tomography (MDCT) remains the most appropriate imaging modality for the diagnosis and staging of RCC. The aim of this work was to compare the findings of MDCT with surgical pathology to determine the accuracy of delineating tumor size, localization, organ confinement, lymph node metastases, and the extent of tumor thrombus in the renal vein and inferior vena cava.

Methods: The clinical, surgical, and anatomo-pathologic records of 99 patients treated by nephrectomy (radical or partial) for solid renal tumors at Theodor Bilharz Research Institute and Nasser Institute from 2005 to 2011 were reviewed retrospectively. All cases were staged pre-operatively with abdominal MDCT (pre- and post-contrast enhancement) in addition to the routine biochemical, hematological, and radiological work-up. The tumors' histologic types were determined according to the WHO classification of renal tumors in adults in 2004, and staging was updated to the TNM 2010 system. Data were analyzed using the t-test.

Results: The mean age was 52 (range 21-73). Seventy-eight patients were males, and 21 patients were females (Male/Female ratio: 3.7:1). There were no significant differences in the mean tumor size between radiographic and pathologic assessments in different tumor stages. The overall incidence of lymph node invasion in surgical specimens was 76%, whereas MDCT showed a positive incidence in 68.4% of cases (false negative result in 7 cases, 7.6%).

Conclusion: Our findings indicated that MDCT urography is an accurate method to estimate renal tumor size, lymph node, vascular and visceral metastases preoperatively. Also, preoperative staging of renal tumors with MDCT represents a valuable and accurate tool.