Quantitative fluorescence in situ hybridization and its ability to predict bladder cancer recurrence and progression to muscle-invasive bladder cancer

Fluorescence in situ hybridization (FISH) testing is used to detect bladder cancer in urine specimens. The purpose of this study was to determine whether there are associations between the percentage of chromosomally abnormal cells by FISH and time to bladder cancer recurrence and progression to metastasis. Clinical records were searched to identify patients with urine FISH results, history of non-invasive bladder cancer, and at least one follow-up pathological diagnosis. Covariates analyzed included age, gender, smoking status, treatment after FISH, cystoscopy result, and prior stage of bladder cancer. The percentage of abnormal cells (hazard ratio [HR] 1.03, 95% CI 1.02-1.03; P < 0.001), age (HR 1.02, 95% CI 1.00-1.03; P = 0.033), male gender (HR 0.60, 95% CI 0.41-0.87; P < 0.001), treatment (HR 0.37, 95% CI 0.25-0.55; P < 0.001), and history of TIS/T1-stage tumors (HR 1.66, 95% CI 1.23-2.24; P = 0.001) were significantly associated with time to cancer recurrence. Time to invasive cancer was significantly associated with the percentage of abnormal cells (HR 1.02, 95% CI 1.01, 1.03; P < 0.001), history of TIS/T1 tumor (HR 3.73, 95% CI 1.88, 7.38; P = 0.001), and treatment (HR 0.33, 95% CI 0.13, 0.83; P = 0.019), suggesting that the percentage of abnormal cells independently predicts cancer recurrence and progression to invasive disease in patients with a history of non-invasive bladder cancer.