NEW YORK (Reuters Health) – The urinary marker assay ImmunoCyt can rule out bladder cancer in select patients with atypical urine cytology, according to a report online April 13th in European Urology.
“Atypical cytology is a fairly common finding,” Dr. Badrinath R. Konety from University of Minnesota in Minneapolis told Reuters Health by email. “There are at least two urinary marker tests (ImmunoCyt and Urovysion) that have now been demonstrated to be useful in this setting to arbitrate atypical urine cytology. It remains to be seen if this will lead to greater adoption of this strategy into clinical practice.”
Dr. Konety and colleagues assessed whether the use of ImmunoCyt as a second-level reflex test performed routinely in all patients with a reading of atypical urine cytology could arbitrate results and improve diagnostic efficiency. Their analysis included 506 assays in 324 patients, followed by cystoscopy within 90 days.
Overall, reflex ImmunoCyt provided 75.2% sensitivity, 49.3% specificity, 36.4% positive predictive value, and 83.7% negative predictive value.
Among the 102 patients with no prior history of urothelial cancer, an improved sensitivity (85%) and specificity (59%) led to a higher negative predictive value (94%).
In subgroup analysis, test performance was consistent between patients with a history of low-grade and high-grade or carcinoma in situ disease.
Among 131 patients who underwent a biopsy or transurethral resection within 90 days of ImmunoCyt testing, sensitivity was 86.5% and specificity ranged from 20% to 25%, resulting in low positive and negative predictive values
“When used as a reflex test to arbitrate atypical urine cytology, a negative ImmunoCyt result can be used to predict a negative cystoscopy in select patients,” the researchers conclude. “The high negative predictive value can be used to modify the urgency and nature of further urologic work-up, both in those without a history of urothelial cancer and in those with a history of low-grade urothelial cancer in which a routine follow-up schedule with fewer cystoscopies can be maintained despite a reading of atypical cytology.”
“Reflex testing using ImmunoCyt is simple and convenient,” Dr. Konety said. “It can increase the specificity of the cytology. Due to its relatively low cost, it may be the ideal adjunct to cytology. The high negative predictive value of ImmunoCyt can help limit additional testing in patients with atypical cytology. This can decrease costs and limit morbidity.”
“We would like to obtain longer follow up of patients to see if those with negative ImmunoCyt ultimately develop tumors and if so the grade, stage, and location,” Dr. Konety added. “We would also like to compare results of reflex ImmunoCyt to reflex Urovysion FISH (fluorescent in-situ hybridization) in a prospectively identified cohort of patients with atypical cytology.”
Eur Urol 2012.