Do Urine Cytology and FISH Analysis Have a Role in the Follow-Up Protocol of Upper Tract Urothelial Carcinoma?

Background: Current guidelines recommend a stringent follow-up regimen that includes interval cystoureteronephscopy, CT urography, and selective urine cytology sampling for upper tract urothelial carcinoma (UTUC) patients undergoing endoscopic treatment and management. There are no recommendations regarding FISH analysis. Our purpose was to assess the efficacy of cytology and FISH as part of the follow-up protocol and its significance to clinical decision-making in this scenario. Methods: The medical records of all patients who managed endoscopically for UTUC at our institute between 2014 and 2022 were retrospectively analyzed. Demographic and clinical data, histology, cytology, and FISH results were collected. FISH analysis was considered malignant according to Paris criteria. Results: During the study period, 62 patients underwent 561 ureteroscopies as part of the treatment and follow-up regimen of low-grade UTUC. Urine from the affected upper tract was sampled for cytology in 377 procedures, and FISH analyses were performed in 273. In 75.4% of FISH analyses, the result was different from the cytology results: FISH found malignant aberrations in 15.5% of cases where cytology was benign. Furthermore, FISH classified all the cells defined as atypical via cytology as either benign or malignant. In only one case (0.17%), the urinary cytology report changed the follow-up regimen. Conclusion: Cytology may be omitted from the follow-up protocol of low-grade UTUC. In the handful of cases cytology does assist the diagnosis of UTUC, there is an additional benefit to performing FISH analysis, particularly when cellular atypia is reported in the cytology results.