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A Publication of the Patrick C. Walsh Prostate Cancer Research Fund


Blue Light Shows Urothelial Cancer

Date: 11/05/2019

Blue Light Shows Urothelial Cancer
Look at the difference a change in light makes! The white light used with conventional cystoscopy is on the left; the same views using blue light are on the right. A and B show a small papillary lesion – which really shows up well under blue light cystoscopy, highlighted by red fluorescence. C and D show areas (in red under blue light cyscoscopy) that need to be biopsied.

Have you ever gone to an event and had your hand stamped? The stamp may not show up at all unless someone shines a black light on it, and then there it is, plain as day! Pathologist Andres Matoso, M.D., and colleagues have discovered something similar by changing the color of light – from white to blue – used during cystoscopy. “Carcinoma in situ (CIS; abnormal cells that may become cancerous and spread; also called stage 0 disease) is difficult to visualize with white light cystoscopy,” says Matoso, “but blue light cystoscopy, using photosensitizing agents, improves detection rates” of urothelial cancer, also known as transitional cell carcinoma, the most common type of bladder cancer.

In a recent study, Matoso and colleagues assessed the sensitivity of blue light cystoscopy, and compared the results with the final pathology diagnoses (see photo to right). “We also focused on cells that looked abnormal in blue light cystoscopy and had a pathology diagnosis that was suspicious, but not diagnostic of CIS. We found that blue light cystoscopy allows us to detect CIS that would have been under-diagnosed with the conventional white light cystoscopy.” Their results were published in Human Pathology.

Bladder cancer that invades the muscle wall: Matoso and colleagues recently completed another study to evaluate the clinical significance of invasive urothelial carcinoma that might be invading the muscle wall of the bladder – but again, it might not. “Urothelial carcinoma that invades the muscle wall has a much worse prognosis than cancer that is non-invasive, or that just invades superficially,” says Matoso. “While most patients can confidently be diagnosed as having either superficial or muscle-invasive bladder cancer, there’s a small subset of cases that are difficult to classify.”

In this study, Matoso and colleagues looked at invasive urothelial carcinoma that appeared ambiguous for muscle wall invasion on initial transurethral resection of bladder tumor (TURBT). They compared clinical and pathologic information from patients whose urothelial carcinoma was considered ambiguous to samples from patients with muscle-invasive disease and from patients diagnosed with superficial bladder cancer who underwent radical cystectomy (surgery to remove the bladder). “We found that the great majority of patients who have ambiguous invasion on initial TURBT turn out to have advanced disease” when the removed bladder specimen is examined. “This emphasizes the need for early repeat TURBT – or even consideration of early cystectomy to lower the risk of worse pathological findings, and to prolong survival.”

This study was published in the World Journal of Urology.