Does hexaminolevulinate detect chromosmal aberrations in the false-positive bladder biopsies?

Introduction:With the introduction of photosensitizing drugs allowing photodynamic diagnostic (PDD) for the bladder cancer, diagnosis has become more accurate. The main limitation of the procedure is the false-positive detection rate, which ranges from 12% to 60%. The onset of multifocal transitional cell carcinoma has been described as a panurothelial disease as it evolves because of genetic defects that are present also in histological negative urothelial tissue. Objective:We analyzed chromosomal patterns of false-positive lesions in the PDD and compared them with the findings of random biopsies with the intent to observe if hexaminolevulinate detects chromosomal aberrations in histological healthy tissue. Patients and Methods:Included in the study were 18 patient,16 men and 2 women, with a mean age of 70.5 (range=47-83) years. All had false-positive PDD confirmed in the histology. A random sample was taken from all patients. The chromosomal patterns of all samples were analyzed with fluorescence in situ hybridization (FISH). Results: From January 2012 until November 2014, a total of 266 bladder biopsies were performed in 30 patients with a positive PDD finding. Eighteen patients had false-positive biopsies in a total of 40 biopsies. In these patients, a total of 25 random biopsies were also performed. Seven out of 18 patients showed chromosomal aberration in 10 (25%) of the false-positive biopsies. All 10 biopsies showed aneusomy of the Locus 9p21 (p16), 6 (13%) aneusomy of chromosome 3 and 5 biopsies (12,5%) aneusomy of chromosome 7 and chromosome 17. In 4 patients, the FISH of the control random biopsy was positive. One had an aneusomy of Locus 9p21 (p16), the other three had anuesomy also for chromosomes 3, 7 and 17. Conclusion:In our trial, over a third of the patients with a false-positive PDD finding already express chromosomal aberrations in these lesions.