Inadequacy of biopsy for diagnosis of upper tract urothelial carcinoma: implications for conservative management.

OBJECTIVE: To report changes in grade and stage between initial diagnostic and repeat biopsies or resection for urothelial carcinoma (UTUC) and investigate the consequences for endoscopic management. Ureteroscopic management of upper tract UTUC is an alternative to nephroureterectomy, which is less invasive and preserves renal function. However, concerns about potential understaging, inaccurate grading, incomplete resection, lack of effective tertiary chemoprevention, and need for ureteroscopic surveillance limits it appeal.
METHODS: Clinicopathological records of patients with UTUC treated at our institution were reviewed. Fifty-six patients with a histologic diagnosis of UTUC and 2 or more consecutive biopsies or biopsy followed by surgical resection were included, resulting in 65 biopsy specimens.
RESULTS: The median interval between diagnostic biopsy and subsequent biopsy or resection was 6 weeks (range, 1 week to 60 months). Change in grade from the diagnostic biopsy occurred in 24 of 65 biopsies (37%), including 9 in which diagnosis changed from low to high grade. Change in the stage from the diagnostic biopsy occurred in 25 of 65 biopsies (38%). Overall, 24 (43%) patients were reclassified from low-grade, noninvasive disease to high-grade and/or invasive disease.
CONCLUSION: A change in grade and/or stage from the diagnostic biopsy occurred in more than one third of patients with UTUC managed conservatively. Because of the short median time interval between biopsies, this finding likely represents variability in tumor sampling on biopsy. Because of the concerns of undergrading and understaging, appropriate patient selection and vigilant endoscopic surveillance are mandatory for UTUC managed endoscopically.