Is photodynamic diagnosis using hypericin better than white‐light cystoscopy for detecting superficial bladder carcinoma?

Abstract

To review the initial clinical results of photodynamic diagnosis (PDD) using hypericin (a new photosensitizer for PDD that helps to label flat urothelial tumours to facilitate biopsy) for the early detection of superficial bladder carcinoma, as flat noninvasive tumours of the bladder may be missed during conventional white-light cystoscopy (WLC) if there is bladder overdistension or ongoing cystitis. Between 1 January 2001 and 30 October 2004, 41 consecutive patients (mean age 66.1 years, sd 9.1, range 46-81) had transurethral resection for bladder cancer. Hypericin was introduced intravesically for 2 h before cystoscopy. Immediately after WLC, fluorescence cystoscopy (FC) was used at the same location and the same bladder site inspected using violet light. FC findings, e.g. positive or negative red fluorescence, were documented for each specific bladder site examined, and the exact location sampled for biopsy. The mean (sd, range) bladder capacity of the patients was 431 (86, 300-650) mL. In all, 179 biopsies were taken from the 41 patients; urothelial cancers were found in 41% (74) and 80% (33) had macroscopically visible bladder tumours; 40% (71) of the biopsies were positive under FC and 86% (61) of the 71 FC-positive biopsies showed cancer on histology. Twenty-five biopsies (14%) were positive on FC but not WLC. PDD testing with hypericin had a sensitivity of 82% (61/74) and specificity of 91% (95/105), vs WLC, at 62% (46/74) and 98% (103/105), respectively. The PDD test had a positive predictive value of 86% (61/71) and a negative predictive value of 88% (95/108), vs 96% (46/48) and 79% (103/131), respectively for WLC. There were no reports of significant complications after the procedure. PDD using hypericin shows promise, as it has a higher sensitivity but equivalent specificity than WLC. It can be used to detect flat lesions not seen on WLC. PDD testing is also well tolerated with minimal side-effects.