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 0.21cm. In T1a group, the difference was 0.33cm. 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.

Is tumor size a reliable predictor of histopathological characteristics of renal cell carcinoma?

To determine whether smaller tumor size is associated with less-aggressiveness in renal cell carcinoma [RCC]. Series records of 505 patients diagnosed with RCC were retrospectively reviewed and the data concerning tumor size and pathological information were extracted and analyzed. Five hundred and eight RCCs were identified. The mean tumor size was 5.02 +/- 2.70 cm. No correlation was detected between the size of tumor and the histological subtype. The overall nuclear grade distribution was 57.1% and 42.9% for low-grade and high-grade disease, respectively. Each 1 cm increase in tumor size was associated with a significant increase in the odds ratio of high-grade disease by 1.46. 91.1% were found low-stage lesions and the odds ratio for the association of high-stage disease with each 1 cm increase in tumor size was 1.67. Multinomial models revealed that each 1 cm increase in the tumor size was associated with a 35% increase in renal capsule involvement and 66% renal vascular invasion. The cut-off point of tumor size in renal vascular invasion was 5.6 cm. Tumor size is not an independent predictor for the histological subtype of RCC. However, it is closely correlated to histopathological features, with the indications that the greater the tumor size, the more aggressive potential the RCC is