The accuracy of multidetector Computed Tomography for preoperative staging of renal cell carcinoma.

PURPOSE The purpose of this study was to evaluate the accuracy of multidetector computed tomography (MDCT) in the preoperative staging of renal cell carcinoma (RCC). MATERIALS AND METHODS We retrospectively reviewed the clinical and pathological records of 312 patients with RCC who underwent staging MDCT before surgery. Radiographic findings were compared to the findings at surgery and pathological examination. All staging used 2009 updated TNM classification. RESULTS The difference in tumor size between radiographic and pathological findings was 0.21 cm. In T1a group, the difference was 0.33 cm. Agreement between MDCT and histopathological findings was moderate for T staging (Kappa = 0.469), fair for N staging (Kappa = 0.322), and excellent for M staging (Kappa = 0.932). The sensitivity and specificity of MDCT in detecting perinephric fat invasion were 32.26% and 85.87%, in detecting tumor thrombosis were 84% and 100%, in detecting adrenal gland invasion were 60% and 95.79%, in detecting lymph node involvement were 50% and 96.36%, in detecting distant metastasis were 100% and 99.67%, respectively. In regard to stage grouping, 237 of 314 patients were correctly staged by MDCT, with an overall accuracy of 75.48%. CONCLUSIONS MDCT with a dynamic contrast protocol is able to delineate RCC with high accuracy. However, a great portion of tumors were overstaged by MDCT because of overestimation of tumor size and poor visualization of infiltration of the perinephric fat. In addition, nodal metastatic lesion evaluation relies on node size only and remains a difficult task.