Hypothesis / aims of study
The Artificial Urinary Sphincter (AUS) is the gold standard for post-prostatectomy incontinence. However, surgical implantation of the AUS is not without complications, and the timing of implantation remains controversial. We evaluated the factors that affect the survival of the AUS after radical prostatectomy (RP) and radiotherapy (RT).
Study design, materials and methods
Ninety-six prostate cancer patients who underwent AUS between 2011 and 2020 were included. Comorbidities (hypertension (HTN) or diabetes mellitus (DM)) were evaluated. Complications were divided into mechanical, erosion, infection, and sub-cuff atrophy. Comparisons were made for two different groups. The first group consisted of patients who did not have RT compared with those who received RT at some point. The second group was compared between those patients who had RT followed by salvage-RP and those who had RP and then salvage-RT. Kaplan-Meier was used for the AUS survival with SPPSv29.
Results
Sixty-seven patients underwent radical prostatectomy (RP) followed by AUS and twenty-nine patients received radiotherapy (RT). Eighteen of these patients underwent salvage-RT and eleven salvage-RP. The median age was similar in both groups (76.85 vs. 77.45), and the mean follow-up was 9.45 years.
Comorbidities were found to be associated with complications by 17% for HTN (HR 95% 1.17 [0.61-2.26], p-value 0.62) and 27% for DM (HR 95% 1.27 [0.60-2.68], p-value 0.52).
Complications:
1) Non-RT group vs RT :
No differences were found: mechanical (15 versus 3, p=0.11), erosion (3 versus 2, p=0.6), and sub-cuff atrophy, which was higher in the non-RT group (8 cases vs. 3 cases, p=0.81). Only the infection was higher in the RT group, with a p-trend value (p=0.08).
2) Salvage-RT group vs Salvage-RP:
Seven complications were found in the salvage-RT (3 infections, two cuff atrophy, and two mechanical) and five in the salvage-RP (one infection, one cuff atrophy, one mechanical, and two erosions) (p=0.73).
AUS Survival:
AUS survival was found to be higher in the non-RT group in the first 20 months after the implant surgery. The salvage-RT group had higher AUS survival than salvage-RP (62 months (95% CI [13.8-111.9]) vs 29.8 months (95% CI [0-64])).
Interpretation of results
The results of the AUS and the relationship with the RT are open to debate, given that they have implications for clinical decision-making. Analysing which factors could predict the outcomes and success of the AUS is important. Taking this into account, one of the parameters is the comorbidities. We found no statistically significant differences between groups, however, both HTN and DM were found to be at high a risk by 17% and 27%, respectively.
The complication rates observed in both groups were found to be comparable: 41.8% for the non-RT group and 41.3% for the RT group. Furthermore, there were no observed differences in the incidence of complications between salvage RT and salvage RP. However, the infection rate was found to be higher in the salvage RT group, with three complications arising in seven cases. This finding is likely attributable to the RT modality.
About the AUS survival, it was found that this was higher in the non-RT group during the first 20 months following the implantation. A further comparison of patients who received RT revealed that AUS survival was higher in the salvage RT group than in the salvage surgery group (62 months (95% CI [13.8-111.9]) vs. 29.8 months (95% CI [0-64])). This finding provides a valuable indication of the optimal timing for AUS implantation, which is likely to be most beneficial for patients who have undergone RP followed by RT.