Impact of Pathology Review in Adverse Histological Characteristics and pT Stages of Upper Tract Urothelial Cancer in a Multicenter Study

Purpose

Pathology reviews for upper urinary tract cancer (UTUC) remained scarce in the literature. Here, we reported the interobserver variation among the review and local pathologies of featured histologic characteristics for UTUC.

Methods

Patients who underwent definitive surgical treatments for UTUC were retrospectively reviewed for eligibility of pathology review. In the Taiwan UTUC Collaboration cohort, 212 cases were reviewed, of which 154 cases were eligible for pathology review. Agreement between original pathology and review pathology was measured by the total percentage of agreement and by simple kappa statistics. The prognostic impact was analyzed by the Cox regression model with the estimation of hazard ratios (HR) and 95% confidence intervals.

Results

There were 80 women and 74 men enrolled in this study, and the median age at treatment was 71.7 years. The agreement is moderate agreement for surgical margin status (87.7%; κ = 0.61), tumor grade (82.5%; κ = 0.43), tumor invasiveness (76.6%; κ = 0.45), lymphovascular invasion (70.8%; κ = 0.42) and T stage (67.5%; κ = 0.52). The interobserver agreements for perineural invasion and variant histology identification were slight. Kaplan–Meier analysis for disease-free survival revealed comparable results in local and review pathology for localized (Tis, Ta, T1–2) or advanced T stage (T3–4).

Conclusions

Pathology review of UTUC had minimal impact on clinical practice based on current available disease treatment guidelines. However, significant interobserver variations were observed in featured adverse histopathological characters.

Upper urinary tract urothelial carcinoma with intratubular spread

Upper urinary tract urothelial cell carcinomas (UUT-UCs) are uncommon and are defined as urothelial carcinoma involving the urinary tract from the renal calyces, renal pelvis to the distal ureter. One well-known an peculiar histopathological finding in UUT-UC is urothelial carcinoma with intratubular spread (retrograde spread within renal tubules). However, this special feature has not been systematically studied. We therefore collected a total of 53 consecutive cases of upper urinary tract urothelial carcinomas (UUT-UCs), and studied the clinical and pathological features of intratubular spread (IS). A cocktail stain comprised of antibodies PAX8 and p63 together with PAS was validated and employed to facilitate the study of intratubular spread. Seventeen cases (31.5%) showed intratubular spread demonstrated by either H&E stain and/or the cocktail stain. All of the 17 cases wit intratubular spread had tumor involvement of the renal calyx; the majority of these (14/17, 82.4%) were high grade urothelial carcinoma and the remainder (3/17, 17.6%) were low grade. 4 of 17cases (23.5%) were non-invasive. We classified intratubular spread into 4 different types, based on histopathological patterns: pagetoid, typical, florid, and secondary invasion from intratubular spread. In conclusion, study shows intratubular spread of urothelial carcinoma is fairly common phenomenon in UUT-UC and is associated with a variety of clinical-pathological features. High grade UUT-UC tends to have more extensive intratubular spread and secondary invasion into renal parenchyma. Distinct morphological characteristics as well as the staining pattern from a unique cocktail stain help to identify and evaluate intratubular spread of urothelial carcinoma. Recognizing these different types of intratubular spreading (IS) is crucial for accurate staging of some upper urinary tract urothelial carcinomas (UUT-UCs).