Metallic stents efficacious for malignant ureteral obstruction

San Diego-A new study suggests that metallic Resonance ureteral stents are a good option for management of malignant ureteral obstruction because they promote strong long-term outcomes.

The stents offer "excellent treatment outcomes and improved cost effectiveness," said study co-author Philippe E Spiess, MD, MS, of Moffitt Cancer Center and the University of South Florida, Tampa.

According to Dr. Spiess, metallic ureteral stents offer an alternative to traditional polymer stents and require annual exchanges instead of once every 3-4 months.

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"Over recent years, several retrospective studies have been performed to validate their efficacy and longevity in the setting of malignant ureteral obstructions of various genitourinary and non-genitourinary etiologies," he said. "However, there is limited data on their long-term viability and outcomes."

Only one kind of metallic ureteral stent-the Resonance-is available for use in the U.S., said study co-author Timothy Juwono, MD, of the University of South Florida Morsani College of Medicine.

For the new single-center study, which was presented at the 2017 American College of Surgeons Clinical Congress in San Diego, the authors tracked 148 metallic Resonance ureteral stents that were placed in 80 cases of malignant ureteral obstruction from 2009-2016.

"Our patients were managed with Resonance metallic ureteral stent for a range of between 24-83 months with a median of five stent exchanges during the study duration. The median stent life was 10 months, which is 6-7 months longer than the traditional polymer stent," Dr. Juwono said.

Next: 85.1% success rate

The success rate was 85.1% for stents that were successfully placed in patients who didn't die or become lost to follow-up.

"These patients were excluded since meaningful data, meaning stent success or failure, could not be determined," Dr. Juwono said.

The stent failure rate was reported at 9.6%, "which is well below that reported of polymer stents," Dr. Juwono added. "Malignant ureteral obstruction is a difficult condition to manage, with reported failure rates of up to 40%-50% with polymer stents reported with refractory malignant obstruction and in the long-term setting. Our data indicates that Resonance metallic ureteral stents are, in fact, more effective and resistant to ureteral compression provided they are used in the right clinic setting; ie, malignant ureteral obstruction."

Another 5.3% of stents had to be removed due to intolerability (flank pain, hematuria, and/or urinary frequency) within 2 months of placement.

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Study co-author Adam Baumgarten, MD, of the University of South Florida Morsani College of Medicine, described the study findings this way: "No stent is able to stay indwelling lifelong, but this study shows that most placed metallic ureteral stents are capable of staying indwelling for their indicated duration, which saves the patient frequent minor surgical procedures with their inherent risk and cost."

What about cost?

"In our prior study, we actually calculated the total cost-OR time, anesthesia, equipment, and the cost of the stent-of using metallic stents and compared it to polymer stents," Dr. Spiess said.

As reported in the 2014 study, the authors found that the annual estimated cost for polymer stents exchanged every 90 days ranged from $9,648-$13,128 but dropped to $4,211-$5,313 for those exchanged a median of every 288 days (Int Braz J Urol 2014; 40:225-31).

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