Endoscopic stent insertion is commonly used in the palliative setting for patients with malignancy of the upper and lower gastrointestinal tract (from the esophagus to the rectum). However, in the urologic field, the use of metallic stents remains a challenge.  We tried to evaluate the efficacy of a self-expandable covered metallic stent in the prostatic urethra, by comparing benign prostatic disease and prostate cancer (PC).

The study protocol was approved by the ethical review board of our institution. We reviewed 42 cases of insertion of self-expandable covered metallic stents with barbs. The self-expandable covered metallic stent (Taewoong Medical, Gyeonggi-do, Korea) was placed in a retrograde manner. The stent consisted of 0.2-mm nitinol wire with 2-mm barb for preventing migration and was covered with expanded polytetrafluoroethylene. The cohort was divided into 2 groups: non-PC and PC. Uroflowmetry variables, residual urine volume, International Prostate Symptoms Score (IPSS), quality of life (QOL), and duration from stent insertion to removal were surveyed. Logistic regression analysis was conducted to predict early stent removal within 3 months. All statistical tests were 2-tailed, with p<0.05 considered to indicate statistical significance.

The PC group showed similar baseline characteristics, including age, body mass index, and prostate volume, to the non-PC group. The average flow rate (4.9 vs. 2.0 mL/s, p=0.044), peak flow rate (6.3 vs. 11.8 mL/s, p=0.010), flow time (25.9 vs. 49.3 s, p=0.018), residual urine volume (34 vs. 124 mL, p=0.019), IPSS (10 vs. 26, p<0.001), and QOL (2 vs. 5, p<0.001) improved after stent insertion compared with before stent insertion. There was no difference in the median time to stent removal between non-PC and PC (6.0 vs. 5.7 months, p=0.627). Medical history, prostate volume, PC, and stent size were not significant factors affecting early stent removal within 3 months.

Initially, we were concerned that a self-expandable covered metallic stent might be less effective in PC because the general status of patients with cancer may be worse than that of patients with benign disease, and PC can compress the urethra or bladder structurally. In our study, patients in the PC group had poorer Charlson comorbidity index and much higher AUR incidence than those in the non-PC group. We compared patients with and without PC who complained of urethral obstructive symptoms. These patients could be typical subjects for TURP or other procedures, and 9 patients had a history of another operation. There is no gold standard for obstructive symptoms in patients with terminal disease or those who are difficult to anesthetize. In castration-resistant PC with lower urinary tract symptoms, palliative TURP could show a 30–40% failure rate. Our study offers an additional solution for such cases. There was no difference between patients in the non-PC and PC groups in baseline characteristics such as age, body mass index, and prostate volume. Consequently, the PC group did not show inferior results to the non-PC group in terms of the incidence of, reason for, and time to stent removal. In addition, the presence or absence of PC did not influence early stent removal within 3 months. We confirmed the significant effect of the stent by using objective and subjective tools of evaluating urinary function. The use of a stent can be a valid option for both patients with and those without PC.

Our self-expandable covered metallic stent was maintained for about 6 months, and uroflowmetry variables and IPSS and QOL scores were improved after the stent insertion. The PC group, which showed similar baseline characteristics such as age, body mass index, prostate volume, and operation history, showed a comparable maintenance period to the non-PC group. Considering the characteristics of this stent, patients with a short life expectancy, unsuitability for general anesthesia, prior radiation therapy, and failure of previous operation for prostatic obstruction can be the proper candidates for stent insertion.