High Apoptotic Index in Urine Cytology Is Associated with High-Grade Urothelial Carcinoma

Abstract

BACKGROUND The significance of apoptosis and its association with high-grade urothelial carcinoma (HGUC) in urine cytology has yet to be determined. METHODS A computerized search of the study laboratory information system was performed over a 3-year period for all urine cytology specimens processed using the SurePath liquid-based preparation technique. Only those cases with correlating surgical pathology obtained within 6 months after the urine cytologic samples were included in the current study. Cases from ileal conduit samples were excluded. A semiquantitative numerical scoring system (apoptotic index) was used to assess the amount of pyknosis or karyorrhexis, with 0 indicating none, 1 indicating < 10 per 10 high-power fields, 2 indicating 10 to 30 per 10 high-power fields, and 3 indicating > 30 per 10 high-power fields. Statistical analysis using the Pearson chi-square test was performed. RESULTS A total of 228 cases including 105 benign cases, 79 cases of HGUC, and 44 cases of low-grade urothelial carcinoma (LGUC) diagnosed on follow-up surgical pathology were selected. A score of 0 was observed in 70 benign, 11 HGUC, and 8 LGUC cases; a score of 1 was observed in 31 benign, 21 HGUC, and 23 LGUC cases; a score of 2 was observed in 3 benign, 27 HGUC, and 9 LGUC cases; and a score of 3 was observed in 1 benign, 20 HGUC, and 4 LGUC cases. CONCLUSIONS Excluding ileal conduit urine specimens, the finding of a high apoptotic index (score ≥ 2) with the presence of pyknosis or karyorrhexis in ≥10 per 10 high-power fields in the urine cytology appears to be significantly associated with HGUC (P<.05).