Hybridization Assay Monitors Urothelial Cell Cancer

The FISH assay was used with routine follow-up in the monitoring of patients with a previous history of NMIUCC, which has a high tendency to recur and affected patients must be monitored regularly using invasive cystoscopies.

Scientists at Hospital del Mar Research Institute, (Barcelona, Spain) prospectively studied an unselected cohort of patients under surveillance for a previous history of NMIUCC. A total of 248 examinations in 223 patients were analyzed. Each exploration was comprised of cytological and FISH microscopic examination of voided urine samples and cystoscopy. The sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values for tumor recurrence of all three techniques were determined.

Urine samples were prepared using the ThinPrep liquid-based cytology technique (Hologic Inc, Bedford, MA, USA). The UroVysion assay (Abbott Laboratories. Abbott Park, IL, USA) is a multitargeted fluorescence in situ hybridization technique designed to detect chromosomal aberrations associated with bladder cancer: aneuploidies of chromosomes 3, 7, and 17 and loss of 9p21. The sensitivities of FISH and cystoscopy were not found to be significantly different, 92.9% and 82.1%, respectively. The specificities of FISH and cystoscopy were 92.7% and 89.7%, respectively. The PPV and NPV of FISH were 53.5% and 97.2%, respectively, whereas those of cystoscopy were 63.4% and 98.9%, respectively. No significant differences were found between these two tests. In contrast, the sensitivity and specificity of cytology were 14.3% and 99.5%, respectively.

The authors concluded that the FISH assay is a useful initial monitoring tool in patients with a previous history of NMIUCC. A negative FISH result strongly indicates that no tumor is present without the need for an invasive cystoscopy, whereas a positive FISH result strongly indicates that a tumor is present, requiring invasive cystoscopy to detect the tumor features. Given the lack of statistically significant differences in the FISH and cystoscopy results, they proposed that FISH could be a useful initial diagnostic tool in the surveillance of patients with a previous history of NMIUCC. The study was published in the December 2011 issue of the journal Cancer Cytopathology.

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