Presentation Authors: Kassem Faraj*, Yu-Hui Chang, Kyle Rose, Paul Andrews, Erik Castle, Aqsa Khan, Mitchell Humphreys, Robert Ferrigni, Christopher Wolter, Scott Swanson, Mark Tyson, Phoenix, AZ
Introduction: Mitomycin C (MMC) and Thiotepa are two intravesical agents that are effective in reducing recurrence in the perioperative management of low grade, non-invasive bladder cancer. There are few data comparing the efficacy between these two agents and no studies comparing these agents in the context of single-dose perioperative instillation. Herein we performed the first comparative study to test the hypothesis that a single perioperative intravesical MMC instillation provides longer cancer free intervals than Thiotepa.
Methods: This is a retrospective study that reviewed the charts of patients who underwent a cystoscopic bladder mass excision for a small, low grade, treatment-naÃ¯ve, noninvasive, wild-type urothelial carcinoma of the bladder and received either intravesical Thiotepa (30mg/15cc) or Mitomycin (40mg/20cc) between 2002-2016. Data for demographics, comorbidities, operative information, surveillance, and recurrence was collected. The primary outcome was disease-free survival. The comparison of the average effect between treatment groups was performed by a doubly robust estimation approach that specified both outcome and treatment models simultaneously.
Results: In 154 total patients, 84 and 70 patients received intravesical MMC and Thiotepa, respectively. There were no statistically significant differences between the groups with respect to age, gender, race, BMI, smoking status, or baseline comorbidities. There were no statistically significant differences in mass size, tumor multifocality, or tumor grade between the groups. There were no differences in unadjusted (Figure 1) recurrence rates (MMC: 36% vs. Thiotepa: 46%, p=0.33) at a similar median length of follow up (MMC: 20.4 vs. Thiotepa: 22.8 months, p=0.46). A doubly robust estimation was then performed using logistic regression to model the probability of recurrence. This analysis yielded no differences in the recurrence rates between the two groups (OR 0.65; 95% CI: 0.33-1.31, p=0.23). No episodes of myelosuppression or frozen pelvis were identified in either cohort.
Conclusions: As single-dose perioperative agents, both Thiotepa and MMC result in similar recurrence free survival rates. Larger prospective studies are needed to confirm the external validity of these observations.
Source of Funding: This study was generously supported by funding from the Robert D. and Patricia E. Kern Center for Health Care Delivery Science, the Christian Haub Family Career Development Award for Cancer Research Honoring Dr Richard Emslander, and the Eric and Gail Blo