Introduction: In the management of superficial bladder cancer with intravesical chemotherapy (IVCT), the relationship between agent dose, treatment efficacy and the incidence of damage to healthy urothelium remains unclear. Most IVCT agents act by injuring DNA. We examined the relationship between IVCT agent concentration and induced DNA damage in superficial bladder cancer and normal urothelium. Materials and methods: Single-cell suspensions (110) were derived from transurethral biopsies of superficial bladder tumour (13 patients) and normal urothelium (eight patients). Each cell suspension was incubated for l h with either saline (control) or IVCT agent (doxorubicin, epirubicin. mitomycin C or thiotepa) at a concentration of 2. 20 or 200 ug/mL. Each cell suspension was then processed via a gel electrophoresis (comet) assay which quantifies nuclear damage (DNA strand breaks) in individual cells. Results: For all IVCT agents, there was an increase in the frequency of DNA strand breaks with increasing drug concentration. This rise was more marked for bladder tumour than for normal urothelium. IVCT agent Mean (SD) % DNA damage concentration normal urotheliwn bladder tumour (μg/ml.) Efi MMC f-pi MMC 0 5.7(1.7) 6.4(1.3) 22.7(7.3) 14.7(1.1) 2 28.8(6.7)* 13.0(3.7)* 46.3(6.71* 38.0(4.2)* 20 31.2(5.5)* 24.8(4.6)* 48.2(7.7)* 38.4(5.3)* 200 42.5(5.6)* 32.5(4.3)* 66.5(6.8)* 41.4(5.3)* * P < 0.05) when compared with control values by Mann-Whitney U-nonparametric testing; Epi. epirubicin. Similar dose-response relationships were also found for doxorubicln and thiotepa. Conclusion: The most commonly used IVCT agents cause doserelated DNA damage. Increasing agent dose may be more effective in ablating tumours or preventing recurrence, but may also increase damage to healthy urothelial DNA.
|Number of pages||2|
|Journal||British journal of urology|
|Issue number||SUPPL. 4|
|Publication status||Published - 01 Dec 1998|
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