Improved Detection of Bladder Tumors Reduces Cancer Recurrence

Researchers at the Mayo Clinic (Rochester, MN, USA), the University of Texas M.D. Anderson Cancer Center (Houston, TX, USA) and other institutions conducted a large, multi-center phase III clinical trial of the fluorescent agent hexaminolevulinate, which involved 766 patients in 28 centers in the United States and Europe. The researchers compared use of the traditional white-light cystoscopy with photodynamic diagnosis (PDD) cystoscopy using a special light source and lenses that can switch from white to blue light, designed specifically for use with hexaminolevulinate. The study enrolled patients with higher risk of tumor recurrence who had either multiple papillary noninvasive bladder cancers or papillary tumors that had recurred within a year of being treated. All patients received an examination with white-light cystoscopy, and half were randomized to receive the agent--which was instilled into a patient's bladder prior to the therapeutic procedure--and blue light examination.

The researchers found that the new technology detected at least one additional Ta/T1 tumor in 16.9% of the 278 patients randomized to blue light. There was also a 46% increase in detection of high-risk bladder cancers known as carcinoma in situ (CIS), using the blue-light technique. Subsequently, the researchers looked at 402 patients with Ta/T1 tumors who completed the study, and found a significant reduction in tumor recurrence in patients diagnosed with fluorescence cystoscopy (36%), compared with patients in the white-light group (46%). In all, the new diagnostic technique found more of the most common bladder tumors than the traditional white-light detection method in almost 17% of the patients, and demonstrated a 22% relative reduction in the recurrence rate within nine months of the procedure. The study findings were presented at the annual meeting of the American Urological Association, held during April 2009 in Chicago (IL, USA).

"The cancers appear bright red compared to normal tissue, which is a lighter blue-green; it is quite dramatic. One sees bladder tumors in a whole new light,” said study presenter urologist Lance Mynderse, M.D. "Using the blue light, it is much easier to tell when we have removed all the tumor in the bladder; when no fluorescence remains, we really have improved our effectiveness in ridding the patient of the cancer.”

The fluorescent agent hexaminolevulinate (Hexvix), developed by Photocure ASA (Oslo, Norway), initiates a series of biochemical reactions in malignant cells, which result in significant, preferential accumulation of photoactive porphryins; when the blue light is turned on, the tumors emit a red fluorescence.

Related Links:
Mayo Clinic
University of Texas M.D. Anderson Cancer Center