Preceding transurethral resection of a bladder tumor (TURBT) with 2 doses of intravesical mitomycin-C (IMMC) is a safe and effective method for reducing non-muscle-invasive bladder cancer (NMIBC) recurrence and progression following TURBT, according to results from a phase 2 study published online ahead of print in Journal of Urology.

Currently, instillation of IMMC is recommended directly following TURBT for NMIBC. However, “a lack of compliance occurs due to the associated complications,” wrote Hye Won Lee, MD, National Cancer Center, Goyang, Korea, and colleagues, who conducted this phase 2 study to assess the safety and efficacy of IMMC administered prior to TURBT in this patient population.

This single-center, open-label, parallel-arm trial enrolled 99 patients with NMIBC scheduled to receive TURBT. The patients were randomized on a 1:1 basis to receive 2 doses of 40mg/20mL IMMC 1 day and 4 hours before TURBT (intervention; n = 49) or no treatment before TURBT (control; n = 50). The primary end point was recurrence-free survival (RFS), and secondary end points included adverse events.

Of the 99 enrolled patients, 77 were eligible for analysis. The duration of the study enrollment was 52.4 months, and 61 patients have been followed for at least 10.4 months with no incidence of recurrence. In the intervention arm, 3 patients showed recurrence, compared with 8 patients in the control group. The 1-year RFS rate in the intervention group was 97%, versus 89% in the control group.

According to Dr Lee et al, neoadjuvant IMMC reduced  the relative recurrence risk by 63% (hazard ratio, 0.37; 80% 1-sided confidence interval, -∞ to 0.65; P = .11). No patients had disease progression in the intervention group, whereas 3 in the control group did (P = .051).

In the intervention group, 15% of patients experienced drug-related adverse events, all grade 1 or 2; the most common adverse events were urinary frequency (9.1%) and hematuria (6.1%).

“The use of neoadjuvant IMMC instillation immediately before operation appears feasible and demonstrated promising therapeutic efficacy in patients with NMIBC without significant [adverse events],” Dr Lee and researchers concluded.

The authors suggest future larger studies with longer follow-up in this patient population comparing both neoadjuvant IMMC and post-TURBT IMMC, as well as the feasibility and therapeutic efficacy between mitomycin-C and gemcitabine in the neoadjuvant intravesical setting.

Source:

Lee HW, Lee HH, Park EY, et al. Clinical efficacy of neoadjuvant intravesical mitomycin-c therapy immediately before transurethral resection of bladder tumor in patients with non-muscle-invasive bladder cancer: Preliminary results of a prospective, randomized phase II study. J Urol. Published online October 12, 2022. doi:10.1097/JU.0000000000003002