Patency period of a metallic ureteral stent and its determinants in patients with malignant ureteral obstruction: a prospective review

Background Malignant ureteral obstruction caused by extrinsic compression of a primary malignant tumour or by metastatic disease is an indicator of poor prognosis with a median life expectancy of about one year. We examined clinical outcomes following Resonance Metallic Ureteral Stent (Cook Medical, Bloomington, IN) placement in patients with malignant ureteral obstruction. Methods This was a prospective study of patients with malignant ureteral obstruction who underwent Resonance Metallic Ureteral Stent placement from April 2016 to March 2021. We registered 21 patients (27 collecting systems) with malignant ureteral obstruction and observed them prospectively. The patients first underwent polymer ureteral stent placement followed by replacement with a metallic ureteral stent one month later. Primary outcome was the metallic ureteral stent patency period based on both serum creatinine and the level of hydronephrosis; secondary outcomes were factors affecting patency period and stent-related complications such as symptoms of obstruction (flank pain), bladder irritation, haematuria, and urinary tract infection (presence or absence of fever). Results The study comprised 21 patients (six men, 15 women) with a mean age of 72 years. The median stent patency period in days was not available (NA) (95% CI 210–NA) due to the inability to extract this value from the Kaplan–Meier curve because the event rate did not reach 50%, and the one-year patency rate was 59.2% (95% CI 23.2–82.9). A normal serum creatinine (0.65 to 1.07 mg/dL for men and 0.46 to 0.79 mg/dL for women) one week after polymer ureteral stent placement was a significant factor affecting the long-term metallic ureteral stent patency period. There were no major complications. Conclusion The Resonance Metallic Ureteral Stent was effective and safe for patients with malignant ureteral obstruction. A normal serum creatinine level one week after placement of a polymer ureteral stent may predict a longer patency period of metallic ureteral stents in patients with malignant ureteral obstruction.

Effect of Metallic Ureteric Stents on Magnetic Resonance Imaging: Implications for Malignant Ureteral Obstruction

Metallic ureteric stents are increasingly used for the management of malignant ureteric obstruction, a commonly encountered complication in urological and other malignancies. However, there has been limited evaluation of complications associated with these stents, including those that might arise from the use of magnetic resonance imaging (MRI). While most devices are deemed nominally “MRI-safe,” their implication on the quality of imaging produced has not been evaluated in clinical trials, and in our practice, significant artefact has been encountered with some ureteric stents—specifically, the Teleflex Rüsch DD tumour stent—compromising image quality and diagnostic certainty.

A Double Metachronous Ureter Metastasis following Curative Resection of Rectal Cancer

A malignant ureteral obstruction is most often due to primary tumors of the ureter. However, it can occur secondary due to external tumor compression or metastatic infiltration. Distant metastases to the ureter are extremely rare. We present a case of a rare double distant metachronic metastasis to the right ureter as well as to the right renal pelvis in a 58-year-old female with a history of anterior resection for rectal cancer 2 years earlier. She presented with recurrent urinary tract infection and right hydronephrosis caused by an ureteral mass. The patient underwent a right nephroureterectomy via laparotomy. Two metastases of the rectal cancer in the ureteral mucosa were verified at histology. On account of the infiltration of the right ureteral orifice, a completion transurethral resection of the tumor was performed. A follow-up 3 and 6 months later showed no signs of tumor relapse and the patient was doing well. The differential diagnosis of malignant ureteral obstruction in patients with history of colorectal cancer should include the rare possibility of distant metastasis from the primary tumor.