Can Endoscopic Appearance, Selective Cytology, and Pathological Sampling During Ureteroscopy Accurately Predict Tumor Grade of Upper-Tract Urothelial Carcinoma?

This study examined the reliability of the various parameters obtained in diagnostic ureteroscopy for upper-tract urothelial carcinoma (UTUC) in predicting the degree of differentiation in the final pathological report after radical nephroureterectomy (RNU). We conducted a retrospective review of patients undergoing RNU at a single tertiary hospital between 2000 and 2020. Only patients who underwent preoperative diagnostic ureteroscopy (URS) were included. The results of urine selective cytology, endoscopic appearance of the tumor, and biopsy taken during ureteroscopy were compared to the final pathological report. In total, 111 patients underwent RNU. A preliminary URS was performed in 54. According to endoscopic appearance, 40% of the "solid"-looking tumors were high grade (HG), while 52% of those with a papillary appearance were low grade (LG). Positive cytology predicted HG tumors in 86% of cases. However, 42% of patients with negative cytology had HG disease. The biopsies acquired during URS showed that HG disease findings matched the final pathology in 75% of cases. However, 25% of patients noted as being HG, based on URS biopsies, were noted to have LG disease based on nephroureterectomy biopsies. Full analyses revealed that 40% of the cases diagnosed as LG based on the URS biopsies actually had HG disease. Direct tumor observation of papillary lesions, negative cytology, and biopsies indicating LG disease are of low predictive value for classifying the actual degree of tumor differentiation. No single test can accurately rule out HG disease. In light of the rising use of neo-adjuvant chemotherapy in UTUC, a reliable predictive model should be developed that accurately discriminates between HG and LG disease.