RARP quickly became the most widespread surgical procedure for prostate cancer in recent years . Despite technical and methodological improvements in RP, UI does occur and negatively affects quality of life . Assessment of predictors associated with urinary continence has been tried in many studies [7,15,18,19]. This is important for patients and surgeons . Early expectation of a good outcome would help reduce patient anxiety, while early estimation of postoperative outcomes could help surgeons identify patients who are at high risk of UI and counsel them on postoperative expectations for urinary continence.
It has been reported that urinary continence is stable 12 months postsurgery . Hence, many previous reports mainly address CRs within one year post RARP. Few data are available at more than 24 months follow-up for urinary continence. In our study, CRs one, two, three, and four years after surgery were 78.77%, 79.96%, 79.51%, and 76.50%, respectively (Table 1). No significant differences in continence outcomes were observed during the four-year follow-up. Our results certified that one year after RARP was the stable continence period . Few studies have evaluated CR rates after 12 months. Shao and assists reported that CR at 24 months after RARP were 89.4%, while Xylinas and co-workers reported a 24-month urinary continence rate of 88% using the no-pad definition [7,21]. Murphy and colleagues reported a 36-month urinary continence rate of 94.7% using the no-pad or safety pad definition . Mandel and assistants reported that CRs at 24 and 36 months after surgery were 89.5% and 90.9%, respectively . Our CR 48 months after RARP was 76.50%, which we believe is the longest follow-up on the topic to date.
While many studies have evaluated predictors of urinary continence within one year after surgery, these studies either included a relatively small number of patients or had discontinuous follow-up. To our knowledge, this is the first study to evaluate predictors of continence one to 48 months after RARP in a relatively large sample.
In our cohort, CRs one, three, six, and 12 months after RARP were 40.62%, 60.92%, 71.38%, and 78.77%, respectively (Table 1). CR gradually improves at these times. Our results are in agreement with the recent study by Honda and assists which found that CRs at one, three, and six months were 40.7%, 63.0%, and 73.1%, respectively . The definition of postoperative urinary continence varied among several studies. There is no consensus on UI after RP so far . We chose the definition of incontinence as any leakage of urine, which seems to be the strictest. It has been reported that continence rate one year after RARP is 69% to 97% [1,25]. Our overall continence rate at 12 months was 78.77%, based on defining continence as no pad use. Although it is not excellent, it is within the average range.
To identify predictive factors for urinary continence, it was divided into two categories: early continence ( < 3 months) and late continence ( > 12 months) .
In general, PLND was selectively performed for sampling purposes in intermediate- and high-risk patients . One month after surgery, PLND in the continence group occurred in 121 patients (45.83%), while it occurred in 217 patients in the incontinence group (56.22%) (P<0.05). Three months after surgery, there were no significant differences in both groups. Logistic analysis showed that PLND was a significant independent risk factor of early urinary continence at one month. Men who had PLND during surgery had a higher risk of UI. Lymphadenectomy may give rise to more transient damage to nerve vessel bundles (NVBs), which affects the recovery of urinary continence. However, with the recovery of body function, this impact is gradually diminishing.
Our logistic analysis showed that NS was a significant independent protective factor of urinary continence at one month, three months, and six months (Tables 5 and 6). This is in line with Reeves’s study which found that avoiding damage to the nerves around the prostate improves urinary continence in the first six months after surgery . Michl and colleagues investigated long-term CRs (12 months) after RP and showed a significant difference between the NS and non-NS groups . The studies by Kadono and Steineck also indicated that NS is associated with urinary continence in the long term [20,29]. Probably important bias in the studies used for the analysis may have influenced the results. However, all the studies showed that NS during the surgery produced better postoperative continence outcomes.
Multiple studies have demonstrated that age is an independent risk factor for return of continence one to 12 months after RARP. Lavigueur-Blouin and co-workers evaluated early continence after RARP . It showed that advanced age was an independent predictor at one month. Kim and colleagues have demonstrated that younger men are most likely to have an earlier return of continence three months after RARP . Greco and assists performed a study that compared continence outcomes in RARP in older men with those of younger men . They showed that CRs at one, three, and 12 months were comparable in two groups, but the older group had significantly lower continence rate at six months. Their results partly agree with those of our study. Shikanov and co-workers demonstrated that age was one predictor of continence return 12 months after RARP, which is partially in accordance with our results . Our results show that age is a significant risk factor of continence six, 12, and 24 months after surgery (Tables 6 and 7). Men of advanced age had a higher risk of UI. Older men have poor endothelial dysfunction, which affects the vascular supply of the NVBs. In addition, it is difficult to perform pelvic floor exercises (PLE) due to an age-related decrease in skeletal muscle and neuronal plasticity mass . All of these may affect functional outcomes.
One thing to point out is that the optimal time to remove the indwelling catheter has not yet been determined. Traditionally, urinary catheter removal has been performed between 10 and 21 days postoperatively . Generally, the catheter is removed three weeks after operation in our center. It is to ensure better healing of the anastomosis. But most patients returned home after operation and removed the indwelling catheter at the local clinic. This leads to the inconsistency of catheter removal and our duration of indwelling catheter seems longer.
Our results must be considered in light of some limitations. First, this is a retrospective study from a single institution, and surgeries were not performed by a single surgeon. Second, we did not analyze all variables due to undocumented surgical steps of the procedure, variations in surgical experience, and differences in pathological reports. Third, although we used the strict definition of continence, the continence conditions were reported by the patients rather than by using a quality questionnaire. Fourth, potential selection bias operating in those selected for the procedure may influence the results. In addition, missing data were unavoidable because many patients were lost to follow-up. Although our study has the aforementioned limitations, it clearly had a large sample size, and the survey of postoperative UI was time-continuous.