High rate of pathologic upgrading at nephroureterectomy for upper tract urothelial carcinoma

Objective: To determine the association between endoscopic biopsy grade and the final pathologic characteristics at nephroureterectomy for upper tract urothelial carcinoma (UTUC). Endoscopic biopsy is an important tool for patients with UTUC because the results can influence the management decisions. Methods: We identified 481 patients who had undergone nephroureterectomy for UTUC at the Mayo Clinic from 1995 to 2008. Of these patients, 184 underwent endoscopic cup or brush biopsy before nephroureterectomy. The biopsy tumor grade was then compared with the tumor grade and stage obtained at nephroureterectomy. Results: Of the 184 patients, 27 (15%) had nondiagnostic biopsy results and 21 (11%) had positive biopsy results with no histologic grade. Of the 24 patients with grade 1 tumors on biopsy, 23 (96%) had the tumor upgraded on the final pathologic examination: 16 (67%) to grade 2 and 7 (29%) to grade 3. Similarly, 23 (40%) of 57 grade 2 tumors on biopsy were upgraded to grade 3 after nephrouretecomy. Only a few patients, 7 (4%) of 184, were found to have a lower histologic grade on the final pathologic examination. The number of patients with invasive UTUC for endoscopic grade 1, 2, and 3 tumors was 9 (38%) of 24, 31 (54%) of 57, and 47 (85%) of 55, respectively. Conclusion: In the context of patients selected for nephroureterectomy, we observed a greater than expected rate of tumor upgrading and invasive disease, particularly in those with low-grade tumors at biopsy. These findings should be considered when electing to use conservative or endoscopic management of low-grade UTUC.