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Charleston, SC--Fluorescent in situ hybridization (FISH) is an effective screening tool for patients who present with signs and symptoms of bladder cancer that warrant an investigation for malignancy, according to a new study from the Medical University of South Carolina. Analysis of the data collected in the study, led by MUSC urology chairman Thomas Keane, MD, showed FISH to be more sensitive than the customary method of cytology.
Of the 300 patient charts reviewed for the study, 134 were new patients and had no history of bladder cancer. Nine malignancies were eventually diagnosed in the population.
"Nine of the malignancies detected were FISH positive, and eight of the malignancies detected were determined as negative by cytology," said H. Mallory Reeves, MD, senior urology resident at MUSC, who presented the findings at the AUA Southeastern Section annual meeting.
FISH is a type of hybridization in which a DNA "probe" is labeled with fluorescent molecules so that it can be seen with a microscope. The assay is designed to detect aneuploidy for chromosomes 3, 7, 17, and loss of the 9p21 locus via FISH in urine specimens.
FISH vs. cytology Among the study population, 104 patients presented with hematuria, eight with irritative voiding symptoms, five with hematuria and irritative symptoms, four with flank pain, and eight with obstructive symptoms. A total of 179 FISH assays were performed, with 31 being positive. A total of 160 cytologies were performed, with two being positive; one was a positive cytology with a concurrent biopsy that showed low-grade TCC, and one suspicious cytology was found to have a concurrent negative FISH and a follow-up negative cytology/negative FISH.
Of the cancers eventually diagnosed, four were low-grade TCC, one was high-grade noninvasive, two were high-grade muscle invasive, one was an upper tract TCC, one was an unspecified TCC, and one was a collecting duct carcinoma. All were FISH positive, while only one was positive by cytology.
"Our data supports the use of FISH and not cytology as an initial adjunct for this subset of patients," Dr. Reeves said.
A question about the cost of FISH versus cytology was raised by an audience member, but Dr. Reeves said the format and setting of the study did not allow for a clear answer to the community urologist.
For one example, the Cleveland Clinic's division of pathology and laboratory medicine said it charges $410 for the test. According to MUSC's cytogeneticist, Daynna Wolff, MD, the cost is approximately $350 per test, Dr. Reeves said.
A comparison of the MUSC data to other urine markers such as NMP-22 (Matritech, Newton, MA) and BTA stat (Polymedco, Cortlandt Manor, NY) is forthcoming, as is an examination of some novel markers, Dr. Reeves noted.
"Those are things you'll be seeing over the next year-and-a-half or so," he said.