Simon CT, et al. - Researchers assessed 117 upper tract urothelial carcinoma (UTUC) resections with upper urinary tract (UUT) biopsy and/or cytology specimens from 2000 to 2016 for the concordance between biopsy, cytology, and resection specimens in a large UTUC population. They noted 26% of renal pelvis UTUC and 36% of ureter UTUC invasive on resection only. They also found previous radical cystectomy among 39% of 18 UTUCs cases reclassified from noninvasive high-grade papillary urothelial carcinoma to invasive high-grade papillary urothelial carcinoma. They noted abnormal cytology results among 88% of high-grade UTUC and 58% of low-grade UTUC. Similar rates of recurrence (38% vs 38%) and metastasis (25% vs 27%) were observed in biopsy-resection pairs with concordant invasion status and pairs with discordant invasion status. They noted a lack of diagnostic neoplastic material in 14% of UUT biopsies. They concluded invasion was more likely to be seen on resection but not biopsy in UTUC cases with previous cystectomy.