In recent years, robot-assisted surgery has been rapidly increasing in popularity. In particular, the shift from open and laparoscopic surgery to robot-assisted radical prostatectomy (RARP) is progressing. Compared to open surgery, RARP is minimally invasive, requiring less blood loss, shorter hospitalization, and smaller incisions. On the other hand, urinary incontinence and decreased sexual function, which are complications inherent to radical prostatectomy, remain significant problems. It is known that urinary incontinence and sexual dysfunction significantly reduce the patient's postoperative quality of life (QOL), so it is important to preserve the function. In Japan, however, many patients who undergo RARP are elderly, and many patients have preoperative sexual dysfunction. In the present study, we evaluated the 5-year long-term outcome of recovery of postoperative sexual function and urinary incontinence by preoperative sexual function in patients who underwent RARP.

Patients who underwent RARP between October 2010 and December 2017 at our department for prostate cancer (stages cT1–cT3 N0 M0) were included in the present study. All patients consented after being fully informed in accordance with the ethics committee at our institution. All study data were analyzed retrospectively. Age, body mass index (BMI), prostate-specific antigen (PSA), prostate volume (PV), clinical stage, Gleason score (GS), and operative results were recorded. The International Prostate Symptom Score (IPSS), the International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF), and QOL index were evaluated before RARP and at 1, 3, 6, 12, 24, 36, 48, 60 months after RARP. Regarding sexual function, the International Index of Erectile Function (IIEF-EF) was used to evaluate before RARP and at 1, 3, 6, 12, 24,36, 48, 60 months after RARP. 
However, Japanese patients are known to be less sexually active than other races. In order to evaluate by sexual function, the IIEF-EF parameters were examined separately for Q1 (How often were you able to get an erection during sexual activity?) less than 2 and Q1 greater than 2. In addition, to see the effect of nerve sparing, cases with Q1 less than 2 and greater than 2 with nerve sparing were also examined.
Data are presented as median value and interquartile range (IQR). Values of p<0.05 were considered significant. Statistical analyses were performed using EZR, which is a modified version of R Commander.

In Table 1 patients’ characteristics are presented. The total number of eligible patients was 172, with 72 patients with Q1 less than 2 and 100 patients with Q1 greater than 2. The only preoperative factor that showed a significant difference between the two groups was age; no other factors showed significant differences (Q1<2: 68, Q1≥ 2: 64, p＝0.00008). There were no significant differences in perioperative outcomes in terms of nerve preservation rate, operative time, blood loss, or console time. Table 2 shows the trends in sexual function and urinary function. The ICIQ-SF in both groups recovered rapidly by the 12th postoperative month and remained almost unchanged thereafter, but neither group recovered to the preoperative level. IPSS recovered to the preoperative level at 6 months postoperatively and remained almost unchanged thereafter, and QOL index deteriorated in the first month postoperatively but recovered to the preoperative level thereafter. There were no significant differences between the two groups. IIEF-EF showed significant differences preoperatively for Q1 less than 2 and greater than 2, and postoperatively for all periods except the first month. However, the group with a preoperative Q1 of 2 or greater also remained significantly lower postoperatively and did not recover to the preoperative level. To evaluate the impact of nerve sparing, cases with nerve sparing were analyzed in the groups with Q1 less than 2 and Q1 greater than 2. Similarly, no significant differences were found with respect to urinary incontinence and QOL. However, compared to the nerve non-sparing group, the patients had a favorable outcome.There was a significant difference between the two groups for IIEF-EF from preoperative to all postoperative periods, and there was also improvement in IIEF-EF, but recovery to preoperative values was not observed.

In the present study, the course of sexual function and urinary incontinence after RARP was examined by preoperative sexual function. The results suggest that preoperative sexual function does not affect urinary incontinence after RARP. On the other hand, urinary incontinence was preserved better in the patients who underwent nerve sparing. For patients with poor preoperative sexual function, producer of nerve sparing did not improve sexual function, suggesting that the impact on sexual function was low, but postoperative urinary incontinence could be maintained. Therefore, aggressive nerve sparing was considered useful in cases where it was possible.

One reason for the poor recovery of sexual function in patients with preserved preoperative sexual function may be a decrease in the frequency of sexual intercourse following RARP. Although we did not examine the frequency of attempted sexual intercourse or its psychological impact in the present study, it is necessary to increase the number of cases and prospectively examine these issues in the future.