Imaging

Abstract

sicker patients to the large medical centers also might tend to increase complication rates. Overall the rates have been stable over time, suggesting that this is about what anyone might expect given a certain level of experience and capability with laparoscopy. Roentgenol. 2004; 182: 217-25 Objective: The purpose of our study was to determine the accuracy of MRI for preoperative staging of renal cell carcinoma using the 1997 TNM classification. Dr. J. Stuart Wolf Jr.Materials and Methods: We conducted a retrospective review of MRI performed in 40 consecutive patients with 42 renal cell carcinomas before radical (n = 35) or partial (n = 4) nephrectomy or exploratory laparotomy (n = 3). The interval between imaging and surgery ranged from 1 to 59 days (mean, 17.9 days). Imaging was performed with T1-and T2-weighted, dynamic gadolinium-enhanced, and time-of-flight sequences. MRI and surgical-pathologic staging was performed using the 1997 TNM staging system. MRI staging was compared with surgical-pathologic staging as the gold standard. Agreement between the two staging methods was assessed using the kappa statistic.Results: Agreement between MRI and surgical-pathologic staging was good for T staging (kappa = 0.72 and 0.78 for reviewers 1 and 2 respectively), poor for N staging (kappa = 0.13, both reviewers), good for M staging (kappa = 0.66, both reviewers), and excellent for the assessment of venous involvement (kappa = 0.93, both reviewers). MRI overestimated the T stage in five patients and the N stage in five and underestimated the T stage in three, the N stage in four, the M stage in one, and the extent of venous thrombosis in two patients.Conclusion: MRI is a reliable method for preoperative staging of renal cell carcinoma using the 1997 TNM classification, in particular for assessing venous involvement. Editorial CommentThe TNM staging system for renal cell carcinoma was revised by the American Joint Committee on Cancer (AJCC) and the International Union Against Cancer (UICC) in 1997. The 1997 TNM staging system for renal cell carcinoma reclassifies tumors using criteria for size and for extent of renal vein / vena cava involvement that are different from the criteria used in the 1987 staging system. With this new TNM staging classification the size limit for T1 tumor was changed from 2.5 to 7 cm.This paper adresses very clearly the problems of the imaging criteria for adequate preoperative evaluation of tumor size, presence of perirrenal extension and regional adenomegaly. It's well known that on the basis of imaging features distinction between stage T1/T2 and stage T3a tumor cannot be reliably made. This occurs because the assessment of invasion of the renal capsule and Gerota's fascia in tumor larger than 3 cm of diameter is based on the utilization of poor predictive radiological