Indications for endoscopic management, as delineated by the European Association of Urology’s Guidelines on Upper Tract Carcinomas in 2013 and summarized in Table 5.2, include unifocal tumor, tumor size (less than 1 cm), low-grade tumors, and no evidence of invasive or advanced disease on imaging [25]. Ideally, cytology should also be negative to rule out the possibility of high-grade disease, as this has been associated with a higher chance of lymphovascular invasion and advanced pathological T stage; however the value of cytology in UTUC is not well investigated [26]. Patients selected for this endoscopic intervention thus must be carefully selected, and demonstrate an understanding that compliance to a close follow-up and surveillance protocol will be essential.

Ureteroscopy can be performed through the retrograde or antegrade fashion, depending on ease of access to the tumor location. With retrograde ureteroscopy, ureteral lesions are easily accessed, versus the use of antegrade (percutaneous) ureteropyeloscopy for renal pelvis lesions that are difficult to access from below, and lower pole calyx lesions, which are also difficult to access through a retrograde approach [24, 27].

Percutaneous therapy has been shown to be safe and effective treatment of low-grade small tumors and it usually requires a second look procedure to assess for any residual disease. It is associated with somewhat higher morbidity than a ureteroscopic approach given its greater invasiveness, and as it is technically more involved, overall this modality is used less frequently than a ureteroscopic approach [25, 28]. However, it has the advantage of being able to debulk larger tumors, as well as easier access to the lower pole collecting system.

Depending on the size of the tumor, these can be biopsied using biopsy forceps or a stone basket, or may be fulgurated using a laser [29]. Because the ureter and renal pelvis is thin walled, caution must be taken not to resect too deeply, as perforation easily occurs. Lasers can then be used for the purposes of achieving hemostasis, to fulgurate the tumor bed, and as resection devices as well. The tissue penetration of the holmium YAG (Ho:YAG) laser is less than 0.5 mm, which provides a decreased risk of thermal damage, and is better suited to treat more superficial tumors. The neodymium:yttrium-aluminum-garnet (Nd:YAG) laser has deeper penetration (5–10 mm), which is helpful in treating larger lesions, especially in the renal pelvis [29, 30].

Endoscopic technique is critical for staging purposes prior to definitive therapy such as with surgical intervention or multimodality therapy with neoadjuvant chemotherapy. Although there have been advancements in endoscopic instruments, there are prognostic factors that are nearly impossible to assess endoscopically, including primary tumor stage and presence of lymphovascular invasion [3].

Some of the limitations to this technique include ureteral perforation and strictures. Ureteral perforation has been reported in approximately 10 % and is managed by discontinuing the procedure, ureteral stenting, or percutaneous nephrostomy tube drainage. Similarly, ureteral strictures are noted to be the most common complication of endoscopic management, at approximately 14 %, which are managed by balloon dilatation, laser incision, or surgical reconstruction [30]. As well, there have been concerns raised regarding the risk of understaging and undergrading [31]. Up to 45 % of cases have been found to be upstaged at nephroureterectomy, although how patients are selected for surgery and how accurately patients are staged clinically radically alter this expectation [32].

Results of endoscopic management are generally evaluated in the context of not only disease survival and recurrence (which should clarify bladder, local, and distant locations), but as well rates of renal preservation and disease progression. Published results of ureteroscopic management have to be considered carefully given the retrospective nature of reports and the highly selected patients they represent. Nevertheless certain consistent results are seen. Patients undergoing endoscopic management generally have a higher local recurrence rate, varying between 15 and 90 %, with an average in these reports of about 61 %. Local recurrence is highly related to tumor grade, with low-grade tumors recurring 14–52 %, and high-grade tumors 40–76 % of the time [33]. Thus, close invasive surveillance is mandatory, given the high recurrence rate of UTUC. Similar data exist with percutaneous therapy, with low-grade tumors recurring 23–35 %, and high-grade tumors 40–42 % of the time, but in this review even more limited number of patients were considered [33].

Bladder recurrences after endoscopic therapy occur between 15 and 70 % in published studies, and these are likely influenced by prior or concurrent bladder disease. Recent data showing a reduction of bladder recurrences after nephroureterectomy with single-dose instillation of chemotherapy would suggest that instituting this practice immediately after endoscopic management may have the same effect [34].

In regard to renal preservation and progression, patient selection affects the results. Nevertheless renal preservation rates for both ureteroscopic and percutaneous therapy are generally favorable, ranging from 50 to 100 % [35]. It should be noted, however, that this is usually associated with multiple procedures. Progression is strongly dependent on tumor grade, with very few well-sampled low-grade tumors progressing, whereas high-grade tumors have a higher likelihood of progression [17].

There have also been concerns about causing metastatic disease by pyelovenous or pyelolymphatic seeding with instrumentation, but this has not been substantiated by several studies which have investigated this issue [36, 37]. Similarly, concerns exist about seeding a percutaneous tract if treatment is performed through this technique, but this is rarely reported and unlikely with proper patient selection with those with low-grade tumors. There is, however, a substantiated and real risk of bladder recurrence, as noted above and likely influenced by a prior history of bladder cancer [38, 39]. Thus patients require lifelong bladder surveillance.