Single-dose perioperative mitomycin-C versus thiotepa for low-grade noninvasive bladder cancer

Mitomycin-C (MMC) and thiotepa are intravesical agents effective in reducing the recurrence of low-grade noninvasive bladder cancer when instilled perioperatively. No studies have compared these agents as a single-dose perioperative instillation. This study tests whether there is a difference in recurrence-free survival in patients with low-grade noninvasive bladder cancer who received intravesical MMC versus thiotepa.

A retrospective review was performed of patients who underwent cystoscopic excision of a bladder mass identified as a small, low-grade, treatment-naïve, noninvasive, wild-type urothelial carcinoma of the bladder and who received either intravesical thiotepa (30 mg/15 cc) or MMC (40 mg/20 cc) between January 1, 2002, and January 1, 2016. Data were collected for demographic characteristics, comorbid conditions, operative information, surveillance, and recurrence. The primary outcome was disease-free survival. Cohorts were compared via the doubly robust estimation approach, which used logistic regression to model the probability of recurrence.

Of 154 total patients, 84 received intravesical MMC; 70, thiotepa. No statistical differences were shown between groups for age, sex, race, body mass index, smoking status, or baseline comorbid conditions; mass size, tumor multifocality, or tumor grade; and unadjusted recurrence rates (MMC, 36.0%; thiotepa, 46.0%; p = .33) at similar median follow up (MMC, 20.4; thiotepa, 22.8 months; p = .46). The robust logistic regression analysis yielded no differences in recurrence rates between MMC and thiotepa (OR, 0.65 [95% CI, 0.33-1.31]; p = .23). No episodes of myelosuppression or frozen pelvis were identified.

As single-dose perioperative agents, both thiotepa and MMC were associated with similar recurrence-free survival rates.