Accuracy of cytology, cystoscopy results challenged

Montreal-Cystoscopy and cytology are the default gold standards for surveillance of recurrence and progression of transitional cell carcinoma of the bladder, but the accuracy of those standards may be tarnished by subtle-to-significant variations in procedural steps that begin with specimen collection and conclude with analysis and reporting of findings.

"To our knowledge, there is only one study [of variability in urine cytology], and it showed that the tests were quite uniform among cancer referral centers, academic institutions, and community laboratories, so we were surprised by the results," Serge Benayoun, MD, chief resident in the University of Montreal's urology program, told Urology Times.

Data were available from 2,542 patients at 10 institutions. All had a history of TCC, and all TCC recurrences were confirmed pathologically. Of these, 898 patients (35%) presented with recurrence. The incidence of recurrence between institutions ranged from 14% to 54%. The inter-institutional accuracy of the test's ability to predict recurrence ranged from 63% to 89%. The ability of the test to predict recurrence in high-grade tumors ranged from 63% to 89%, and the ability to predict recurrence in tumors staged at T2 or higher ranged from 66% to 100%.

Where do weaknesses lie?

Pierre I. Karakiewicz, MD, head of the prognostics unit and associate professor in the department of urology at the University of Montreal, noted that a weakness in this initial report was that the study was not designed to identify the strongest or weakest steps in a diagnostic procedure that contains many steps.

Drs. Benayoun and Karakiewicz intend to pursue these issues through detailed studies designed to find exactly where discrepancies appear and how they might be resolved. They noted that the present data are more than a clinical curiosity because consequential diagnostic decisions are based on cytology reports.

"First, we are going to look at what is happening in our institution. We are going to collaborate with our pathologists and take a close look at each step in the process to identify those that are most likely to contribute to low yields in cytopathology," Dr. Karakiewicz said.

"I think this should be the first step at every institution," said Dr. Benayoun. "Each center should confirm the accuracy of their urine cytology and not assume that the results will be similar to what has been published."

Both physicians noted weakness in the study that they hope to correct at some future date.