Malignant ureteral obstruction (MUO) is a common condition for urologists to manage. MUO may result from obstruction of a primary urothelial tumor, direct invasion from a nonurological malignancy, or compression from a tumor or metastatic lesion. Patients may present with renal colic, mild and nonspecific symptoms, or may be asymptomatic. With the latter, the obstruction is identified through abnormal laboratory findings or hydronephrosis incidentally found on imaging. In addition to pain, MUO may compromise renal function and lead to renal failure.

MUO is associated with unfavorable oncologic prognosis with patients typically having a life expectancy of less than 1 year.¹ Individualized prognosis and end of life or quality of life goals must be considered when deciding whether to intervene with ureteral decompression given that treatment-related side effects can lead to significant decreases in quality of life. Cordeiro et al developed a prognostic model for survival after palliative urinary diversion in MUO.² They found that greater than 4 events related to malignant dissemination (eg, number of metastasis, ascites, pleural effusion) and ECOG (Eastern Cooperative Oncology Group) performance status ≥2 were associated with shorter survival. Median 1-year survival rates were 44.9%, 15.5%, and 7.1% in patients with 0, 1, and 2 of these identified factors, respectively. In the absence of symptoms, observation alone is a very reasonable option for some patients pursuing a palliative approach that optimizes their quality of life. However, even in those with a noncurable diagnosis, ureteral decompression may relieve symptoms or preserve renal function, permitting palliative chemotherapy that may otherwise be contraindicated.

Upper tract decompression can be carried out through several approaches. Cystoscopy with retrograde double-J stenting (DJS) is often the initial management for MUO, but it has limitations. First, in the setting of complete obstruction or altered anatomy, such as with bulky pelvic and retroperitoneal tumors, it may be impossible to advance a wire and stent across the obstruction. Furthermore, traditional DJS composed of polyurethane, silicone, or polymers may fail to provide long-term drainage in almost half of patients with MUO.^3,4 A DJS may also fail from encrustation, migration, patient intolerance, or recurrent infections. Additionally, some polymer stents have a 3- to 4-month dwell time, which necessitates frequent exchanges negatively impacting quality of life. If a DJS fails, placement of tandem ureteral stents (TUSs) is another option. With this approach 2 DJSs are placed side by side. A recent study showed a stent failure rate of 13% with TUSs.⁵ TUSs still have potential drawbacks including still frequent exchanges and increased cost through use of the additional stent.

To better withstand external compressive forces, metallic stents have been developed. The Resonance stent is a 6F DJS constructed of coiled cobalt-chromium-nickel-molybdenum alloy (MP35N). It has an approved dwell time of up to 12 months and is designed to resist encrustation. Stent failure rate has been reported at 33%.⁶ Reducing the number of stent exchange procedures may improve quality of life and be more cost-effective. In our experience, these stents have been more likely to migrate compared with traditional DJS. This can lead to discomfort and malfunction of the stent. Other metallic stent options not available in the United States include the thermo-expandable metal alloy spiral stent (Memokath 051) and the self-expandable metallic mesh stent (UVENTA).

A reinforced silicone stent is also available in the U.S. The Stenostent is a 12F reinforced silicone stent, which tapers to 8F at the coils with a dwell of up to 12 months. In a laboratory model, reinforced stents were shown to be more resistant to extrinsic compression compared to conventional polymer DJS designs.⁷ The wider 12F diameter of the stent can make it difficult to place in stent-naïve patients. We have generally used it in the setting of failure of a standard DJS. Other reinforced tumor stents are also available outside of the U.S. market.

Placement of a percutaneous nephrostomy (PCN) is traditionally the next step when stenting is not successful, not tolerated, or in stent failure. It should also be considered initially in patients needing urgent decompression in the setting of infection. In certain circumstances, patients may prefer PCN over ureteral stenting, and all patients should be counseled on the risks and benefits of PCN and ureteral stent prior to intervention. Advantages of PCN include maximized drainage, ability to be placed under local anesthesia, and easier monitoring of urine output and tube function. Disadvantages include ongoing need for 3-month exchanges and risk of infection, renal complications, and tube dislodgment, and patients actively anticoagulated may not be candidates. Also, the need for external urine collection can have quality of life consequences from impaired physical activity and sleep to negative effects on body image especially in a population likely to have experience with other external drainage or access tubes over the course of their oncologic care. A recent study showed that there were similar negative quality of life effects with both TUS and PCN placement, although patients who had been treated with both preferred TUS over PCN.⁸

Another diversion that can be used in the setting of MUO is permanent subcutaneous pyelovesical bypass. The Detour extra-anatomical urinary diversion is a reinforced silicone-lined tube that is tunneled subcutaneously from the renal collecting system to the bladder, bypassing the ureter. Although more invasive than DJS or PCN, subcutaneous bypass is intended to be permanent, obviating the need for exchange procedures required with the former. In a long-term assessment of 28 patients, the system was in and functioning in 94%, 71%, and 62% of patients at 1, 2, and 3 years, respectively.⁹

In conclusion, MUO can be managed with DJS, tandem ureteral stents, reinforced stents, metallic stents, PCN tubes, or extra-anatomical urinary diversion. All have potential downsides, so quality of life effects of each option, frequency of exchanges, and cost of exchange procedures should be taken into consideration. The indication for decompression should be weighed against goals of care and perceived benefits of decompression, such as ability to receive treatment such as chemotherapy or palliation of symptoms related to obstruction.