Diagnosis of bladder carcinoma using protoporphyrin IX fluorescence induced by 5-aminolaevulinic acid

Objective To report the results of a clinical study investigating the diagn osis of malignant and dysplastic bladder lesions by protoporphyrin IX (PPIX ) fluorescence and to compare them with those from earlier studies. Patients and methods The study included 55 patients with suspected bladder carcinoma (at initial diagnosis or at tumour follow-up visits); 130 bladder biopsies from 49 patients were classified by pathological analysis. All pa tients received an intravesical instillation of 50 mL, of a 3% 5-aminolaevu linic acid (ALA) solution a mean of 135 min before cystoscopy, which was th en performed under white and blue light. Malignant/ dysplastic lesions show ing red fluorescence under blue-light excitation were noted and the increas e in detection rate calculated. Results There were 63 benign and 67 malignant/dysplastic areas biopsied; 10 malignant/dysplastic lesions (four transitional cell carcinoma, two carcin oma in situ, four dysplastia) were not detected during routine white-light cystoscopy but were identified under blue light. Fluorescence cystoscopy im proved the overall diagnosis of malignant/dysplastic bladder lesions by 18% over standard white-light cystoscopy. The improvement was greater for dysp lastic lesions and carcinoma in situ (50%). However, the improvement over s tandard cystoscopy was less than that found by other groups, Conclusion The ALA-based fluorescence detection system significantly enhanc ed the diagnosis of malignant/dysplastic bladder lesions. However, determin ing the optimum drug exposure time requires further investigation using wel l-characterized instrumentation and study protocols, which would then allow comparison of the results from different groups.