[834] Low-Grade Papillary Urothelial Carcinoma (LG-TCC) of the Urinary Bladder: Clinicopathologic Outcome Analysis in a Post WHO/ISUP Classification Single Academic Center Cohort

H Miyamoto, JS Miller, DA Fajardo, TK Lee, GJ Netto. Johns Hopkins, Baltimore

Background: Few long-term single academic center large cohort studies have addressed outcome in patients with primary non invasive LG-TCC following implementation of the WHO/ISUP consensus classification.
Design: Our surgical pathology records were searched for all primary urinary bladder LG-TCCs diagnosed between 1998-2008. All histologic sections initially diagnosed by non-specialized urologic pathologists were reevaluated for accuracy of classification. Electronic medical records were retrospectively reviewed.
Results: A total of 99 cases initially diagnosed as LG-TCC were identified. Of 42 cases initially diagnosed by non-urologic pathologists, 6 (14%) were reclassified as non invasive high-grade papillary urothelial carcinoma (HG-TCC) and were excluded from outcome analysis. Our cohort of 93 primary LG-TCC patients included 68 males and 25 females (mean age: 64.7 years). On follow-up (mean: 37.6; range: 2-107 months), none of our patients died of bladder cancer. Forty-eight (51.6%) patients developed recurrent tumor, including 31 (33.3%) recurrences of LG-TCC or lower grade tumors and 17 (18.3%) recurrences of HG-TCC. 5/17 (29%) patients with grade progression also developed stage progression (3 invasive and 2 metastatic TCC) resulting in 5.3% stage progression rate for the entire cohort. Radical cystectomy was performed in 6 patients. The mean number of recurrence episodes was 2.98 (range: 1-16), mean time to first recurrence was13.9 months (range: 2-72) and mean time to progression to HG-TCC was 26.7 months (range: 2-74). The mean LG-TCC tumor size was 1.68 cm. There was no significant correlation between tumor size and likelihood for recurrence (1.84 cm vs 1.54 cm in cases with or without recurrences respectively) or grade progression (1.58 cm vs 1.47 cm in cases with or without progression to HG-TCC). A trend for higher rate of recurrence was seen in patients with multiple LG-TCC tumors at the time of their initial diagnosis compared to those with a single tumor (Odds ratio = 3.82; p = 0.08).
Conclusions: None of our non-invasive LG-TCC patients died of carcinoma. More than half developed recurrent tumor with 18.3% grade and 5.3% stage progression. Tumor size, time to first recurrence, and number of recurrences did not predict recurrence or progression. Patients with multiple lesions at initial diagnosis tended to have a higher risk for recurrence. A tendency to undercall HG-TCC as LG-TCC continues to exist even in an academic setting.
Category: Genitourinary (including renal tumors)

Monday, March 9, 2009 1:00 PM

Poster Session II # 121, Monday Afternoon