Ureterorenoscopic biopsy and urinary cytology according to the 2004 WHO classification underestimate tumor grading in upper urinary tract urothelial carcinoma.

OBJECTIVES: To determine accuracy of upper tract cytology and ureteroscopic biopsy according to the 2004 World Health Organization (WHO) classification in predicting the correct tumor grade in patients with urothelial cancer of the upper urinary tract (UUT-UC).
METHODS: Pathology reports of 77 nephroureterectomy specimens were retrospectively analyzed for tumor grade and compared with preoperatively gained cytology and ureteroscopic biopsy results. For analysis, the 2004 WHO classification was used.
RESULTS: Overall sensitivity of cytology and biopsy in diagnosis of UUT-UC was 64% and 74%, respectively. Accuracy of cytology and biopsy in predicting high grade cancer was 53% and 58%, respectively. Combination of cytology and biopsy could improve sensitivity (84%) and accuracy (68%), but even for this combination, 15% of high grade tumors were misinterpreted as low grade cancer.
CONCLUSION: Our results show only limited accuracy for preoperative cytology and ureterorenoscopically performed biopsies in the prediction of the correct tumor grading of an UUT-UC. Therefore, we suggest the use of additional diagnostic procedures before the decision for definitive surgical treatment in patients with UUT-UC is made.