Messing EM, et al. - Experts investigated if immediate post-transurethral resection of bladder tumor (TURBT) intravesical instillation of gemcitabine decreased recurrence of suspected low-grade non-muscle-invasive urothelial cancer vs saline. Compared with instillation of saline, immediate postresection intravesical instillation of gemcitabine significantly decreased the risk of recurrence over a median of 4 years among these patients.

Methods

• Researchers conducted a randomized double-blind clinical trial at 23 US centers.
• They enrolled patients with suspected low-grade non–muscle-invasive urothelial cancer based on cystoscopic appearance without any high-grade or without more than two low-grade urothelial cancer episodes within 18 months before index TURBT between January 23, 2008, and August 14, 2012, and followed up every 3 months with cystoscopy and cytology for 2 years, and then semiannually for 2 years. August 14, 2016 was the final date of follow-up.
• For tumor recurrence, progression to muscle invasion, survival, and toxic effects, patients were monitored.
• They participants were randomized to receive intravesical instillation of gemcitabine (2 g in 100 mL of saline) (n=201) or saline (100 mL) (n=205) for 1 hour immediately following TURBT.
• Time to recurrence of cancer was included as the primary outcome, and time to muscle invasion and death due to any cause were secondary end points.

Results

• Results demonstrated that in the intention-to-treat analysis, cancer recurrence within 4 years was seen in 67 of 201 patients (4-year estimate, 35%) in the gemcitabine group and 91 of 205 patients (4-year estimate, 47%) in the saline group (hazard ratio, 0.66; 95% CI, 0.48-0.90; P <.001 by 1-sided log-rank test for time to recurrence).
• Experts noted that among the 215 patients with low-grade non-muscle-invasive urothelial cancer who had undergone TURBT and drug instillation, cancer recurrence was seen in 34 of 102 patients (4-year estimate, 34%) in the gemcitabine group and 59 of 113 patients (4-year estimate, 54%) in the saline group (hazard ratio, 0.53; 95% CI, 0.35-0.81; P=.001 by 1-sided log-rank test for time to recurrence).
• Tumors that progressed to muscle invasion were seen in 15 patients (5 in the gemcitabine group and 10 in the saline group; P=.22 by 1-sided log-rank test) and 42 died of any cause (17 in the gemcitabine group and 25 in the saline group; P=.12 by 1-sided log-rank test).
• There were no grade 4 or 5 adverse events and no significant variances in adverse events of grade 3 or lower.