Urinary cytology with acridine orange fluorescence is highly valuable for predicting high-grade upper urinary tract urothelial carcinoma

Objectives: To evaluate the clinical value of acridine orange fluorescent staining in urinary cytology for the diagnosis of upper urinary tract urothelial carcinoma. Methods and materials: A retrospective analysis was conducted with 510 cases of upper urinary tract urothelial carcinoma (UTUC) in terms of the results of acridine orange fluorescence (AO-F) staining of the exfoliated cells in urine. The percentage of positive AO-F result and the positive predictive value of AO-F for high-grade and muscle invasive urothelial carcinoma were calculated and analyzed in terms of clinical characteristics. Results: The overall percentage of positive AO-F result was 49% in the 510 patients, 54.1% for males and 40.6% for females. AO-F was positive in 51.9% of the patients with hematuria and 36.2% of the patients without hematuria. AO-F was positive in 56.4% of the patients with renal pelvis carcinoma and 42.8% of the patients with ureteral cancer; in 44.6% of the patients with non-muscle invasive carcinoma and 53.5% of the patients with muscle-invasive carcinoma. AO-F was positive in 26.8% of the cases with low-grade carcinoma and 55.3% of the patients with high-grade carcinoma. The positive predictive value of AO-F was 88% for high-grade cancer, and only 53.6% for muscle invasive carcinoma. Conclusions: Acridine orange fluorescence microscopy cannot increase the sensitivity of urine exfoliative cytology in the diagnosis of UTUC. It may be used as a predictor of high-grade UTUC. Acridine orange fluorescence microscopy in urinary cytodiagnosis does not show high value in predicting muscle invasive UTUC.