Does topical instillation therapy influence chromosomal aberrations in superficial bladder cancer?

Patients with a high risk for superficial bladder cancer are treated by topical immuno-or chemotherapy after transurethral resection to reduce the chance of recurrence and/or progression. The aim of this study was to analyse if cytogenetical abnormalities, which are known to be constantly related to bladder cancer, are modified or eliminated by topical immuno- or chemotherapy.

Using fluorescence in situ hybridization (FISH), the influence of topical instillation therapy with Bacillus Calmette-Gúerin (BCG) and Mitomycin C (MMC) on numerical aberrations of chromosomes 7, 9 and 17 was investigated in 25 patients with transitional cell cancer (TCC) of the bladder. Data were compared with histological and clinical outcome. Fifteen TCC patients with similar histological criteria without instillation therapy served as controls. Median follow-up was 30 +/- 2 months.

After BCG treatment 10 of 15 patients (66.6%) developed recurrent and 2/15 (13.3%) progressive disease. Three of 15 patients (20.0%) had no evidence of disease. Numerical aberrations did not change in 8 of the 15 BCG patients (53.3%) and changed to a more aggressive pattern in 40.0% (6/15). Five of 10 MMC treated patients (50.0%) developed a recurrent tumor, 2/10 (20.0%) progressed and 3/10 (30.0%) had no evidence of disease. Four of 10 (40.0%) of these patients showed stable and 5/10 (50.0%) progressive chromosomal patterns. Only one patient in each group with primary chromosomal alterations changed to a regular diploid chromosomal pattern after therapy according to a complete clinical remission.

Even though topical immuno- and chemotherapy may be useful to delay recurrence and progression, chromosomal patterns remain basically unstable.