Accuracy of Grading of Urothelial Carcinoma (UCA) on Urine Cytology: A Measure of Interobserver (INTEROA) and Intraobserver Agreement (INTRAOA).
Michelle D Reid, Adeboye O Osunkoya, Momin T Siddiqui, Stephen W Looney. Emory University Hospital, Atlanta, GA; Medical College of Georgia, Augusta
Background: The accuracy and reproducibility of histologic grading of UCA is well established however cytologic grading of UCA using current World Health Organization (WHO) criteria is not. We determined the accuracy and reproducibility of UCA grading in urine by measuring INTEROA and INTRAOA among 3 pathologists with and without expertise in cytopathology, compared with the gold standard biopsy or resection.
Design: Forty-four UCA-positive urines with tissue confirmation were blindly and independently graded twice (using WHO criteria) by 2 cytopathologists (MR, MS) and 1 genitourinary (GUP) pathologist (AO), with a 1-week-interval between grading. Pathologists were blinded to histologic findings. Coefficient kappa was used to measure INTEROA and INTRAOA. Accuracy was measured by percentage agreement with gold standard, for each pathologist on each occasion and for all pathologists and occasions combined.
Results: Histologic diagnoses included high-grade UCA (32/44, 73%), low-grade UCA (3/44, 7%) and carcinoma in-situ (CIS) (9/44, 20%). Grading accuracy ranged from 64%-89% for the 3 pathologists. AO was more accurate than MR (76% vs 60%) and MS (76% vs 67%) on both occasions combined. Overall accuracy for pathologists and occasions combined was 77% (95% C.I., 72% – 82%). INTEROA was unacceptably low [Table 1].
|MS vs AO||1||0.05||-0.26, 0.36||1.000|
|MS vs MR||1||0.22||-0.08, 0.51||0.235|
|AO vs MR||1||0.37||0.09, 0.66||0.013*|
|MS vs AO||2||0.15||-0.19, 0.50||0.573|
|MS vs MR||2||0.57||0.30, 0.84||<0.001*|
|AO vs MR||2||0.29||-0.01, 0.59||0.053|