Non–muscle-invasive bladder cancer (NMIBC) is characterized by a relatively high recurrence rate and low rate of progression [1], [2]. To mitigate these outcomes, intravesical instillation of mitomycin C or bacillus Calmette-Guérin (BCG) is generally employed [3]. In addition, pembrolizumab, a systemic immunotherapy agent, has recently been approved for the treatment of BCG nonresponsive high-risk NMIBC [4].

Tumor seeding during transurethral resection of bladder tumor (TURBT) has been implicated as a possible cause of early recurrence [5]. To address this issue, a single bladder instillation with mitomycin C administered 6–24 h after surgery has been studied and adopted by international guidelines [6], [7]. The use of postprocedure continuous bladder irrigation has also been shown to decrease early recurrence rates [8].

In vitro studies have demonstrated that bladder cancer cell line cultures exposed to sterile water experience cellular death by an osmotic effect [9], [10]. Translating this phenomenon into clinical practice, use of sterile water for bladder irrigation during TURBT employing monopolar electrocautery system was introduced to minimize tumor cell seeding during the procedure and potentially reduce recurrence rates [11]. Nevertheless, there is lack of clinical evidence to support this approach.

In the current study, we sought to evaluate whether the use of sterile water compared with glycine as the irrigation fluid during TURBT may reduce tumor recurrence and progression rates. In addition, we performed in vitro studies to evaluate the immunogenic effect of both solutions on bladder cancer cells.