Standard cystoscopy uses white light.
Blue light cystoscopy (photodynamic diagnosis PDD)
Instillation of hexaminolevulinate (HAL) 1 – 3 hours prior to cystoscopy.
Taken up by tumour cells which then shine red under the blue light.
Reported to improve detection of tumours and lower recurrence rates (level 1a evidence), particularly with improved detection of CIS.
May be false positives with concurrent UTI or inflammation, and following intravesical treatments – may be lower specificity cf. white light.
Inconvenient and expensive, requires new equipment and patient catheterisation prior to cystoscopy.
No strong evidence that blue light cystoscopy reduces progression rates.
PHOTO trial in UK multicentre RCT 2022 – blue light guided TURBT made no difference for progression or recurrence when used at first TURBT cf. normal TURBT.
Narrow band imaging
Optical image enhancement technology – splits white light into two short green and blue wavelengths.
Improved visualisation of tumours and can distinguish blood vessels at tumour and base.
May reduce recurrence rates when used.