Influencing Factors in Magnetic Resonance Imaging of Prostate to Predict the Time of Regaining Continence after Robot-assisted Radical Prostatectomy
Ping-Hsuan Yu1, Chih-Chieh Lin1,2,3, Hsiao-Jen Chung1,2,3, Tzu-Ping Lin1,2,3,
Eric Yi-Hsiu Huang1,2,3, Tzu-Hao Huang1,2,3, I-shen Huang1,2,3,
Alex T.L. Lin1,2,3, William J.S. Huang1,2,3
1 Department of Urology, Taipei Veterans General Hospital
2 Department of Urology, School of Medicine, National Yang-Ming University
3 Shu-Tien Urological Science Research Center
Purpose: Post-prostatectomy incontinence is bothersome and hard to cure in those patients with moderate to severe urinary incontinence. Predictive factors for longer time to regain continence are of interest and help to illustrate the surgical risk in shared decision making. In this study, we search for possible predictive factors by cancer profiles and by magnetic resonance image findings.
Materials and Methods: Patients planning to perform robot-assisted radical prostatectomy were recruited from January 2019 to July 2020. Demographic data were recorded including age, initial PSA, and Gleason score. MR image was used to obtain the staging, prostate volume, intravesical prostatic protrusion (IPP), urethral angle inside the prostate, and history of previous transurethral resection of prostate (TURP). Specially, we measured the length and width of bladder neck by sagittal and coronal view to calculate the bladder neck area with ellipse area formula. During the surgery, whether the neurovascular bundles were preserved and whether the bladder neck reconstruction was performed would be recorded. After the surgery, the time intervals from the surgery to Foley removal and to continence were reported. We calculate the correlation of time to regain continence with all the factors mentioned above.
Results: Total 85 patients were recruited in this study with median 67 years old and median initial PSA 11.8ng/ml. Most patients have diseases with Gleason score group 2 (40%) and MRI staging T3a (45.88%). According to the MRI findings, the mean prostate volume is 42.16ml with IPP in 22.35% patients and TURP history in 8.24% patients. The mean urethral angle is 57.32˚,and the bladder neck area by ellipse area formula is 8.23cm2. During the surgery, 50% patients got bilateral neurovascular bundles preserved, and 77.65% patients did not undergo bladder neck reconstruction. The median of Foley removal is on post-OP day 4. The median time to regain continence is 46 days. We find a moderate correlation between the bladder neck area and time to regain continence (coefficient 0.510, p<0.001). The larger bladder neck area might also predict a higher possibility of bladder neck reconstruction (area in those with bladder neck reconstruction vs without reconstruction: 9.89 vs 7.78, p=0.002). There is no correlation between time to regain continence with other factors including age, initial PSA, Gleason score, staging, prostate volume, IPP, TURP history, and urethral angle.
The time to regain continence after robot-assisted radical prostatectomy is correlated with the area of bladder neck by pre-op magnetic resonance image. Otherwise there is no correlation between the time to regain continence with other cancer profiles or image parameters.