Could indigo carmine enhance sampling quality in the first transurethral resection of bladder cancer?: a randomised controlled clinical trial

Abstract

BACKGROUND: Bladder cancer is the ninth most common cancer worldwide, and transurethral resection of the bladder tumour (TURBT) is the main technique for pathological diagnosis. In cases of non-muscle-invasive bladder cancer, TURBT also serves as a treatment. Proper execution of this procedure is critical in obtaining high-quality tissue samples that include the detrusor muscle layer, which is essential for determining whether the tumour is muscle-invasive or not, thereby optimising disease management. However, 20–60% of TURBT specimens lack detrusor muscle representation, leading to repeat procedures, and increased recurrence and progression rates. Indigo Carmine is widely used in chromoendoscopy to mark the submucosa during colonic polyp resections, helping to avoid muscle layer resection. This clinical trial aims to study the reverse application and explore if submucosal injection of Indigo Carmine can assist in achieving a more complete TURBT with representation of the muscular layer. OBJECTIVES: The aim of this study is to determine if submucosal injection of Indigo Carmine during TURBT improves the likelihood of obtaining tissue samples with detrusor muscle representation compared to conventional TURBT. Secondary objectives include assessing whether the use of Indigo Carmine leads to more tailored treatment strategies, whether this reduces recurrence and disease progression rates, and whether it proves to be a safer technique compared to conventional TURBT. DESIGN: A single-centre, longitudinal, prospective, parallel-group, single-blinded, controlled, and randomised clinical trial conducted at Hospital Universitari Dr. Josep Trueta. PARTICIPANTS AND METHODS: A total of 68 participants diagnosed with bladder cancer for the first time will be consecutively recruited over a one-year period and randomised into two intervention groups: conventional TURBT or TURBT with submucosal injection of Indigo Carmine. Histological analysis will evaluate detrusor muscle presence and other features, classifying patients into risk groups for appropriate treatment and surveillance. There will be a one-year follow-up to evaluate recurrence, progression, and the need for reintervention