Washington, Apr 27: Mayo Clinic researchers have come up with a novel diagnostic tool that not only helps detect bladder tumours but will substantially reduce the rate at which these cancers come back.

They claim that the new technique helped found more of the most common bladder tumours than the traditional white-light detection method in almost 17 percent of the patients.

It also demonstrated a 22 percent relative reduction in the recurrence rate within nine months of the procedure.

The research team led by Dr Barton Grossman, of The University of Texas M. D. Anderson Cancer Centre compared use of the traditional white-light cystoscopy with new photodynamic diagnosis using a special light source and lenses that can switch from white to blue light.

Making tumours inside the bladder fluoresce red under blue light allows physicians to more easily find and remove them.

The blue light is designed for use with the study drug (hexaminolevulinate), which is instilled into a patient''s bladder prior to the therapeutic procedure.

This acts as a prodrug that initiates a series of biochemical reactions in malignant cells. When the blue light is turned on, the tumours emit a red fluorescence.

"The cancers appear bright red compared to normal tissue, which is a lighter blue-green. It is quite dramatic. One sees bladder tumours in a whole new light," said urologist Lance Mynderse, who practices at Mayo Clinic''s campus in Rochester, Minn.

With the new technique, there was a 46 percent increase in detection of high-risk bladder cancers known as carcinoma in situ (CIS).

"Using the blue light, it is much easier to tell when we have removed all the tumor in the bladder," said Mynderse.

"When no fluorescence remains, we really have improved our effectiveness in ridding the patient of the cancer," said Mynderse.

The findings were presented at annual meeting of the American Urological Association. (ANI)