The portion of the kit that provided the most additional diagnostic value, said Dr. Epstein, was the use of toluidine blue, which was directly swabbed onto suspect sites after visualization with the chemiluminescent light source, per the kit’s directions. Toluidine blue is thought to bind to sites of putative loss of tumor suppressor genes that have been associated with progression of oral mucosal lesions to cancer and in oral cancer. Of the 96 lesions tested with the dye, 34 were false positives, 20 were true positives, and 42 were true negatives. There were no false negatives. The false positive rate was decreased by 59% with the dye, said Dr. Epstein during his presentation of the trial data at the Multidisciplinary Head and Neck Symposium in January.
Explore This IssueMay 2007
Value of the Study
I think the study is valuable, said Ann M. Gillenwater, MD, Associate Professor and Associate Surgeon, at The University of Texas M.D. Anderson Cancer Center in Houston. A lot of the patients and physicians are reluctant to have the biopsy done unless they are really suspicious. A test like this could help tip the balance so that physicians perform only the biopsies that truly need to be done.
The current trial was not designed to determine whether the kit or the dye can detect lesions that would be missed with standard visual exams. That question is key, said Dr. Gillenwater, who is involved in several trials testing other diagnostic devices in oral cancer.
When asked about that issue, Dr. Epstein said that several trials designed to answer that very question are ongoing. In those studies, the toluidine blue dye will be used as an oral rinse rather than applied directly to suspect lesions. One of the multicenter trials is testing the approach in individuals at high risk for oral cancer but who have not yet been diagnosed with the disorder. Participants in the trial must be over 45 years of age, and smoke cigarettes or drink alcohol. Other trials are testing the approach in patients who have been previously treated for premalignant or malignant lesions and are being followed to look for new lesions or recurrence.
In the meantime, the current trial data suggest that the diagnostic kit can reduce the need for biopsies of lesions already identified by visual and chemiluminescent examination.
Dr. Epstein is on the medical advisory board of Zila, Inc. The trial was funded by Trylon Corp Inc. Both companies have financial ties to the ViziLite Plus device kit.