Bladder cancer is associated with unacceptably high rates of recurrence (50–70%) after endoscopic management, and tumour cell implantation is considered to be a leading cause of early recurrence . Over 100 years ago, Albarran and Imbert first proposed that exfoliated tumour cells could implant directly on the urothelium, a theory that has been supported by the work of Kiefer, Hinman, Boyd, and Soloway [2, 3]. Traditional transurethral resection (TUR) relies on in situ tumour fragmentation for tumour removal and specimen retrieval. This practice violates the basic oncological surgical tenet of en bloc resection, promoting tumour cell dispersal and jeopardizing the pathological integrity of the specimen.
It is with great interest that we read the article by Naselli et al.  on a novel technique for en bloc TUR and retrieval of bladder tumours. Their experience adds to a growing body of evidence that has demonstrated the feasibility of en bloc TUR using a variety of techniques [5-12] since the introduction of this concept in 1980 . Unfortunately, these techniques have not gained widespread adoption, perhaps because, as Naselli et al.  point out, endoscopic retrieval of large tumour specimens after en bloc resection has been a challenge. The authors have applied a technique previously described for laparoscopic nephroureterectomy with endoscopic bladder cuff excision , using an electrocautery Collins knife and laparoscopic forceps, to the excision and retrieval of bladder tumours ≤4.5 cm.
We have encountered similar challenges in our own clinical experience with en bloc resection . Before our adoption of an endoscopic nylon mesh retrieval net, we were forced to divide larger tumour specimens before their removal, a technique that we abandoned because of its violation of tumour integrity and its detrimental effects on pathological assessment. In our series of 11 tumours, following endoscopic snare resection (ESRBT), we were able to extract six medium (2–5 cm) and two large (>5 cm) tumours intact through the urethra using the mesh net retrieval system. As it passes through the urethra, the tumour-containing net is compressed and acts as a sieve, allowing excess water to pass but retaining the tumour mass. We believe that this filtration mechanism allows even the largest bladder tumours, which are composed largely of water, to pass with ease through the urethra.
We applaud the authors' work in adapting an existing surgical technique for the en bloc resection and retrieval of small-to-medium bladder tumours. We too continue to refine our own en bloc resection and tumour extraction techniques. These innovative approaches have the potential to significantly improve bladder cancer outcomes by limiting tumour cell dispersal and hopefully reducing recurrences. We are encouraged by promising preliminary results from our group and others suggesting the safety and efficacy of en bloc resection. Through our support and collaborative efforts with other groups, such as Naselli et al., similarly committed to upholding oncological principles in endoscopic bladder surgery, we hope to expedite the refinement of en bloc TUR and tumour extraction.