Loop resection or cold-cup biopsy? A prospective randomised study evaluating the accuracy of detrusor muscle representation during transurethral resection of bladder tumours.

Objective To determine which method—loop resection with electrocautery (LR) or cold-cup biopsy (CCB)—provides superior detrusor muscle representation (DMR) quality in transurethral resection of bladder tumours (TURBT), and to evaluate the impact of surgeon experience on the outcome. Methods This prospective randomized study included 120 patients undergoing TURBT, allocated to either LR (n=55) or CCB (n=65). The procedures were performed by less experienced surgeons (LES) or more experienced surgeons (MES). DMR presence and artefacts were assessed from 216 tumour base specimens. Results DMR was obtained in 88% of CCB and 91% of LR cases (p=0.573). In the MES group, DMR was slightly higher with LR (94%) compared to CCB (89%, p=0.481). Artefacts were observed in 53 participants, with MES showing a significant difference: more artefacts occurred with CCB (63%) than LR (30%, p=0.011). No significant differences in artefact rates were noted for LES. Conclusions DMR rates were similar between LR and CCB. However, artefacts were more common with CCB among MES, which could be explained by the MES possibly crushing the deep muscle sample in an attempt to ensure DMR in the specimen. This suggests that LR may be preferable when performed by experienced surgeons. These findings provide guidance in selecting the optimal sampling technique to improve histological outcomes in bladder cancer.