CT Staging of Renal Cell Carcinoma Using the Revised 1997 TNM Staging Criteria: In Comparison with the Previous One

PURPOSE: To assess the accuracy of preoperative CT staging of RCC and to compare the relationship between T stage and the incidence of metastasis on the basis of the old (1992) and the new (1997) UICC & AJCC tumor classification system. MATERIALS AND METHODS: In 112 cases of surgically resected RCC, the stagings of preoperative CT scans were de-termined retrospectively by two radiologists and were compared with the results of pathologic examinations. In 70 cases which had been followed up over three years after surgery, the incidence of metastasis at initial diagnosis and during the follow-up period was assessed. All cases were reconsidered, and using the old and the new TNM classification, the incidence of metastasis was compared. RESULTS: According to the old TNM classification, 5 cases (4%) were staged at T1, 73(65%) at T2, 21(19%) at T3a, 9(8%) at T3b, 0 at T3c, and 4(4%) at T4. Using the new TNM classification, we also staged 54 cases (48%) at T1 and 24(21%) at T2. Overall, using this new classification, CT correctly staged 79% of patients (88/112) overstaged 15%(17/112) and understaged 6%(7/112) . CT had a sensitivity of 84% and specificity of 91% in new T1 tumors, 71% and 95%, respectively, in new T2 tumors, 69% and 88% in T3a tumors, 78% and 98% in T3b tumors, and 75% and 99% in T4 tumors. CT had a sensitivity of 44% and a specificity of 99% in old T1 tumors, and 82% and 71%, respectively, in old T2 tumors. The incidence of metastasis in CT-staged (cT) tumors was 0% (0/4) in old cT1, 8% (3/39) in new cT1, 29% (4/14) in new cT2, 67% (6/9) in cT3a, and 75% (6/8) in cT3b. CONCLUSION: In the staging of T1 tumors, CT is more sensitive when the new TNM classification is used. Even though the cut off point between T1 and T2 tumors had been in creased from 2.5 to 7.0 cm, T1 tumors staged according to the new system did not show a significantly higher incidence of metastasis than those staged according to the old.

CT Staging of Renal Pelvis Tumor

PURPOSE: To assess the value of computed tomography (CT) in the preoperative staging of transitional cellcarcinoma (TCC) of the renal pelvis. MATERIALS AND METHODS: We retrospectively evaluated the CT TNM staging of 38patients with TCC of the renal pelvis who had undergone preoperative abdominal CT examination between January 1990and January 1998. In CT staging for differentiation between early-stage (TO-2) and advanced-stage disease (T3-T4),three criteria were used, namely the presence or obliteration of the renal sinus fat layer, the smoothness orirregularity of margin between the tumor and renal parenchyma, and the presence or absence of hydronephrosisproximal to the tumor. CT staging was performed by two genitourinary radiologists blinded to the pathologicresults, and was compared with pathologic staging. RESULTS: Pathologic results revealed 19 cases of early stagedisease (TO=8, T1=9, T2=2) and 19 of advanced stage (T3=12, T4=7). Overall CT staging accuracy was 82%(31/38);fourcases were overstaged and three were understaged. In early-stage disease, sensitivity and specificity were 79%,and 84%, and in advanced stage disease were 83% and 80%. Three of four overstaged cases showed hydronephrosisproximal to the tumor. In the second CT staging, using proximal hydronephrosis of the tumor as a criterion forearly-stage disease, the sensitivity and specificity of early-stage disease were 95% and 75%, respectively, andthe specificity of advanced-stage disease was 95%. CONCLUSION: When hydronephrosis proximal to a tumor wasconsidered to be a sign of early stage disease, the CT staging of renal pelvic TCC was highly accurate.