Comparison of radiographic and pathologic sizes of renal tumors

ARtIcLe INFO _________________________________________________________ ___________________ Vol. 39 (2): 189-194, March April, 2013 doi: 10.1590/S1677-5538.IBJU.2013.02.06 IBJU | RadiogRaphic and pathologic SizeS of Renal tumoRS 190 tive size of renal tumors as measured by CT and the pathologic size as determined from surgical specimens (5-7). A difference in tumor size can alter patients’ status regarding tumor stage and prognosis. Also, such discrepancy may result in inadvertent exclusion of a significant number of patients from the opportunity to receive NSS. As maximum preservation of kidney function as well as adequate cancer control is important for the management of RCC, such potential discrepancy should be identified. In this study, we compared the radiographic and pathologic renal tumor sizes of patients in our department who received open NSS or laparoscopic NSS. The main aim of our study was to determine if radiographic size is equal to pathologic size among renal tumors and, if not, whether radiography overestimates or underestimates tumor size and by how much. MAteRIALS AND MetHODS Upon securing approval from the institutional review board of our hospital, we reviewed the records of 169 patients who received open NSS or laparoscopic NSS for renal lesions suspected of malignancy from January 2006 to December 2010. Only the patients who underwent preoperative CT scans at our institution less than 4 weeks before undergoing surgery were included. The size of renal tumors on contrast-enhanced CT scans was measured in three axes including the anterior-to-posterior, superior-to-inferior, and left-to-right axes. The radiographic size was accepted as the largest of these three diameters. Pathologic size was defined as the largest diameter of the tumor as determined by pathologic examination. In patients with multifocal renal tumors, the tumor with the largest diameter was evaluated. The measurement of tumor size by CT scan and pathologic size were performed by one radiologist and one pathologist. The clinical informations, including each patient’s age, gender, tumor side, histologic subtype and primary tumor classification, were recorded. The primary tumor classification was established according to the AJCC 7th edition of RCC TNM-staging system. In our study, patients were categorized according to radiographic tumor size and pathological diagnoses. The mean values of radiographic and pathologic tumor size, along with differences in these sizes, were calculated for each category. The correlation between radiographic and pathologic tumor size was also analyzed. All categorical variables were analyzed by either a two-tailed Fisher’s exact test or a Chi-square test, as appropriate. All continuous variables were analyzed by either a two-tailed Student’s t test or a one-way analysis of variance, as appropriate. Statistical Package for Social Sciences 17.0 software (SPSS Inc., Chicago, IL, USA) was used for statistical analysis. P values < 0.05 were considered statistically significant.