Prognostic importance of combined WHO/ISUP gradi̇ng system in clear cell renal cell carcinoma

Aim: Several parameters have been proposed to predict prognosis in renal cell carcinomas. Although the tumor grade is an important prognostic data in the RCC, there is a low correlation between the observers. The aim of this study was to establish a new grading system based on the combination of different tumor grades in the tumor and the resulting data show the relationship with parameters that are prognostic significance. Materials and Methods: 185 cases of clear cell RCC treated between 2000 and 2013 were included in this study. Demographic features of the disease were obtained from prognostic data from patient records and pathology reports. In fact, the current WHO/ISUP grading was performed by a uropathologist (BT) and a surgical pathology resident (SŞ), and the presence of necrosis in the tumor was also assessed. Combined WHO/ISUP grading system has been applied for tumors with one or more degrees. Combined grade scores are grouped as low, medium and high. The relationship between new grades and prognostic parameters was investigated statistically. Pearson Chi-square test was used for the analyzes. It was also assessed by the kappa statistical test between the two observers and within the observers. Results: According to the Combined WHO/ISUP grading system, 39 (21%) of the 185 cases had the same degree and the remaining 146 (79%) cases had more than one degree. According to the combined grade score group, 77 low grade, 85 intermediate and 29 high grade were evaluated. The agreement between the two observers is "good". Uropatholysis was found to be "excellent" in itself, and "good" in surgical pathology resident. Conclusion: An ideal grading system should have objective criteria, be applicable and repeatable. We think that we have solved the observer inconsistency in large measure by including different grades in the tumor in our study and by including the threshold value we have included in the grading system.