Abstract
The standard of care for upper tract urothelial carcinomas is nephroureterectomy, but there is no consensus on the “best method” for distal ureteral/bladder cuff removal, although most agree it is an important oncologic principle in an otherwise uncompromised patient. Numerous methods have been proposed for management of the distal ureter during open, laparoscopic, and robot-assisted nephroureterectomy (OLR-NUx). Some techniques may necessitate advanced instrumentations (robot-assisted) and/or are technically demanding (transvesical, flexible cystoscopy/laser incision). Many urologists choose to complete transurethral incision of the bladder cuff into perivesical fat before OLR-NUx. Technically, a transurethral approach is often more familiar to the urologist and almost assures complete removal of the distal ureter; however, this potentially exposes the perivesical space to tumor spillage during the nephrectomy phase. Cormio and associates present a novel method to potentially decrease tumor spillage during distal ureter bladder cuff excision using a Fogarty balloon catheter to occlude the ureter.
There are several attractive benefits of the group's technique: it is relatively inexpensive, uses skills familiar to most urologists, and needs minimal additional time or resources. Patient risk appears low, especially when the technique is avoided with distal ureteral tumors. While their technique aims to eliminate extravesical escape of tumor cells from the upper tract during surgery, potential exposure from tumor cells that migrated into the bladder before obstruction still exist. The authors attempt to minimize this exposure by limiting extravasation during resection. In the authors' series, the additional time to complete incision surrounding the ureter appeared short (mean time for excision and repositioning of 21.3 minutes and 19.8 minutes, respectively).
Beyond introducing a novel technique, the article by Cormio and colleagues stimulates thought into another aspect of upper tract urothelial carcinoma management: What influence does upper tract hydraulic pressure have in tumor advancement, both locally and into lymphatic and venous systems?
Intuitively, upper tract pressure has always concerned me. Retrograde pyelography can lead to extravasation and lymphatic entry, and bacteremia is common in obstructed urolithiasis or during stone manipulation with ureteroscopy. Urologists attempt to avoid high pressures in all of these situations. Auge and coworkers 2 demonstrated pressures of 94.4 mm Hg with ureteroscopy in the renal pelvis during stone treatment, a pressure that was reduced to 40.6 mm Hg with an access sheath. Opposing any apparent parallels are retrospective studies failing to support the hypothesis that upper tract hydraulic pressure influences tumor spread. In fact, a study by Ishikawa and associates 3 demonstrated an improved cancer-specific survival after ureteroscopy; however, the authors acknowledge that the result more likely represents selective bias (smaller, indeterminate tumors underwent ureteroscopy/biopsy vs nonbiopsied, larger masses). Even more perplexing are the studies on ureteral tumors vs pelvic tumors: Some studies demonstrate a worse prognosis while others show no significant difference, respectively. Measurement of the level of obstruction was not made, however. 4,5
Circling back to the bacteremia analogy, not all infected upper tracts result in bacteremia with obstruction or ureteroscopy. Perhaps not all upper tract tumors seed the vascular and lymphatics, but does the risk exist? At the very least, should we be more judicious with ureteroscopy and biopsy of enhancing upper tract tumors, reserving it for indeterminate lesions or in morbid patients where endoscopic/nephron-sparing treatment is being considered? Moreover, does preoperative and intraoperative fluid administration alter upper tract pressure when the ureter is clipped or obstructed during surgery? Certainly, these topics warrant further study. Perhaps using the technique of Cormio and colleagues, the ureter can be obstructed with the Fogarty but attached to a bag and drained, thereby reducing pressure and allowing analysis of time-phased samples for tumor cells and pressure transducer measurements.
Cormio and coworkers should be applauded for sharing their ingenuity that may not only stimulate thought and debate, but also challenge us to further study our techniques and refine our management of upper tract urothelial carcinomas to accommodate future improved oncologic outcomes.