RARP quickly became the most widespread surgical procedure for prostate cancer in recent years [16]. Despite technical and methodological improvements in RP, UI does occur and negatively affects quality of life [17]. Assessment of risk factors associated with UI has been tried in many studies [7,14,18,19]. This is important for patients and surgeons [18]. 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 UI is stable 12 months postsurgery [2]. Hence, many previous reports mainly address CRs within one year post RARP. Few data are available at more than 24 months follow-up for UI. In our study, CRs one, two, three, and four years after surgery were 78.77%, 79.96%, 79.51%, and 76.50%, respectively (Table 2). 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 [20]. 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 [22]. 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 12 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 [14]. The definition of postoperative urinary continence varied among several studies. There is no consensus on UI after RP so far [23]. We chose the ICS definition of incontinence, which seems to be the strictest. It has been reported that continence rate one year after RARP is 69% to 97% [1,24]. 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 UI, we defined early continence as return of urinary continence within three months after surgery, just as Lavigueur-Blouin and Hatiboglu described [25,26]. Because UI tends to be stable 12 months after surgery, late continence was regarded as return of urinary continence three months after surgery [2].
In general, PLND was selectively performed for sampling purposes in intermediate- and high-risk patients [27]. However, some surgeons perform routine lymphadenectomy in our center. 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, six, and 12 months after surgery, there were no significant differences in both groups. Logistic analysis showed that PLND was a significant independent predictive factor of early urinary continence at one month. Men who had more PLND during surgery had a higher risk of UI. More 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.
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 [25]. In their group, 44% of patients were pad-free one month after RARP. 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 [28]. Greco and assists performed a study that compared continence outcomes in RARP in older men with those of younger men [29]. 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 [30]. Our results show that age is a significant determinant of continence six and 12 months after surgery (defined as late stages). Men of advanced age had a higher risk of UI. Kumar explained that age may affect functional outcomes in several ways: (1) aged men may have chronic diseases with associated poor urinary function; (2) older men have poor endothelial dysfunction, which affects the vascular supply of the NVBs; and (3) it is difficult to perform pelvic floor exercises (PLE) due to an age-related decrease in skeletal muscle and neuronal plasticity mass [17].
Limitations
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. 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.