A novel nomogram provides improved accuracy for predicting biochemical recurrence after radical prostatectomy / 中华医学杂志(英文版)

BACKGROUND@#Various prediction tools have been developed to predict biochemical recurrence (BCR) after radical prostatectomy (RP); however, few of the previous prediction tools used serum prostate-specific antigen (PSA) nadir after RP and maximum tumor diameter (MTD) at the same time. In this study, a nomogram incorporating MTD and PSA nadir was developed to predict BCR-free survival (BCRFS).@*METHODS@#A total of 337 patients who underwent RP between January 2010 and March 2017 were retrospectively enrolled in this study. The maximum diameter of the index lesion was measured on magnetic resonance imaging (MRI). Cox regression analysis was performed to evaluate independent predictors of BCR. A nomogram was subsequently developed for the prediction of BCRFS at 3 and 5 years after RP. Time-dependent receiver operating characteristic (ROC) curve and decision curve analyses were performed to identify the advantage of the new nomogram in comparison with the cancer of the prostate risk assessment post-surgical (CAPRA-S) score.@*RESULTS@#A novel nomogram was developed to predict BCR by including PSA nadir, MTD, Gleason score, surgical margin (SM), and seminal vesicle invasion (SVI), considering these variables were significantly associated with BCR in both univariate and multivariate analyses (P < 0.05). In addition, a basic model including Gleason score, SM, and SVI was developed and used as a control to assess the incremental predictive power of the new model. The concordance index of our model was slightly higher than CAPRA-S model (0.76 vs. 0.70, P = 0.02) and it was significantly higher than that of the basic model (0.76 vs. 0.66, P = 0.001). Time-dependent ROC curve and decision curve analyses also demonstrated the advantages of the new nomogram.@*CONCLUSIONS@#PSA nadir after RP and MTD based on MRI before surgery are independent predictors of BCR. By incorporating PSA nadir and MTD into the conventional predictive model, our newly developed nomogram significantly improved the accuracy in predicting BCRFS after RP.

Application of U-shaped convolutional neural network in auto segmentation and reconstruction of 3D prostate model in laparoscopic prostatectomy navigation / 北京大学学报(医学版)

OBJECTIVE@#To investigate the efficacy of intraoperative cognitive navigation on laparoscopic radical prostatectomy using 3D prostatic models created by U-shaped convolutional neural network (U-net) and reconstructed through Medical Image Interaction Tool Kit (MITK) platform.@*METHODS@#A total of 5 000 pieces of prostate cancer magnetic resonance (MR) imaging discovery sets with manual annotations were used to train a modified U-net, and a set of clinically demand-oriented, stable and efficient full convolutional neural network algorithm was constructed. The MR images were cropped and segmented automatically by using modified U-net, and the segmentation data were automatically reconstructed using MITK platform according to our own protocols. The modeling data were output as STL format, and the prostate models were simultaneously displayed on an android tablet during the operation to help achieving cognitive navigation.@*RESULTS@#Based on original U-net architecture, we established a modified U-net from a 201-case MR imaging training set. The network performance was tested and compared with human segmentations and other segmentation networks by using one certain testing data set. Auto segmentation of multi-structures (such as prostate, prostate tumors, seminal vesicles, rectus, neurovascular bundles and dorsal venous complex) were successfully achieved. Secondary automatic 3D reconstruction had been carried out through MITK platform. During the surgery, 3D models of prostatic area were simultaneously displayed on an android tablet, and the cognitive navigation was successfully achieved. Intra-operation organ visualization demonstrated the structural relationships among the key structures in great detail and the degree of tumor invasion was visualized directly.@*CONCLUSION@#The modified U-net was able to achieve automatic segmentations of important structures of prostate area. Secondary 3D model reconstruction and demonstration could provide intraoperative visualization of vital structures of prostate area, which could help achieve cognitive fusion navigation for surgeons. The application of these techniques could finally reduce positive surgical margin rates, and may improve the efficacy and oncological outcomes of laparoscopic prostatectomy.

Application of machine learning models in predicting early stone-free rate after flexible ureteroscopic lithotripsy for renal stones / 北京大学学报(医学版)

OBJECTIVE@#To establish predictive models based on random forest and XGBoost machine learning algorithm and to investigate their value in predicting early stone-free rate (SFR) after flexible ureteroscopic lithotripsy (fURL) in patients with renal stones.@*METHODS@#The clinical data of 201 patients with renal stones who underwent fURL were retrospectively investigated. According to the stone-free standard, the patients were divided into stone-free group (SF group) and stone-residual group (SR group). We compared a number of factors including patient age, body mass index (BMI), stone number, stone volume, stone density and hydronephrosis between the two groups. For low calyceal calculi, renal anatomic parameters including infundibular angle (IPA), infundibular width (IW), infundibular length (IL) and pelvic calyceal height (PCH), would be measured. We brought above potential predictive factors into random forest and XGBoost machine learning algorithm respectively to develop two predictive models. The receiver operating characteristic curve (ROC curve) was established in order to test the predictive ability of the model. Clinical data of 71 patients were collected prospectively to validate the predictive models externally.@*RESULTS@#In this study, 201 fURL operations were successfully completed. The one-phase early SFR was 61.2%. We built two predictive models based on random forest and XGBoost machine learning algorithm. The predictive variables' importance scores were obtained. The area under the ROC curve (AUROC) of the two predictive models for early stone clearance status prediction was 0.77. In the study, 71 test samples were used for external validation. The results showed that the total predictive accuracy, predictive specificity and predictive sensitivity of the random forest and XGBoost models were 75.7%, 82.6%, 60.0%, and 81.4%, 87.0%, 68.0%, respectively. The first four predictive variables in importance were stone volume, mean stone density, maximal stone density and BMI in both random forest and XGBoost predictive models.@*CONCLUSION@#The predictive models based on random forest and XGBoost machine learning algorithm can predict postoperative early stone status after fURL for renal stones accurately, which will facilitate preoperative evaluation and clinical decision-making. Stone volume, mean stone density, maximal stone density and BMI may be the important predictive factors affecting early SFR after fURL for renal stones.

Impact of diagnostic ureteroscopy and biopsy on radical nephroureterectomy of upper tract urothelial carcinoma / 北京大学学报(医学版)

OBJECTIVE@#To investigate the impact of preoperative diagnostic ureteroscopy and biopsy (UB) on radical nephroureterectomy (RNU) and the prognosis of upper tract urothelial carcinoma (UTUC).@*METHODS@#The clinical data of UTUC patients receiving RNU between Jan. 2007 and Dec. 2016 were retrospectively collected. The median follow up time was 40 months. The operation time and blood loss of RNU were compared between UB group and non-UB group. Subgroup analyses were conducted according to the time interval between UB and RNU, and surgery methods of lower ureter. The linear regression model was used to adjust for other common factors that impacted operation time.@*RESULTS@#A total of 163 UTUC patients were included in the final analysis. For the lower ureter, open ureterectomies were performed in 91 patients (55.9%), while retroperitoneal laparoscopic ureterectomies were performed in 72 patients (44.1%). A total of 110 (67.5%) patients received preoperative UB. Compared with non-UB group, the average operation time of UB group was significantly longer [(252.5±79.8) min vs. (221.3±79.8) min, P=0.019], but no difference of blood loss was found (median, 50 mL vs. 50 mL, P=0.143). In subgroup analysis, the average operation time of RNU was significantly prolonged when RNU was performed after 1 week of UB (P=0.023). Meanwhile, the median blood loss of RNU increased significantly when it was done after 2 weeks of UB compared with non-UB group (100 mL vs. 50 mL, P=0.012). UB was also significantly prolonged the operation time of RNU in retroperitoneal laparoscopic ureterectomy group (P=0.012). In multivariable analysis, UB (P=0.049), ≥pT3 (P=0.039), pN+ (P=0.018) and ureterectomy method (P=0.005) were independent risk factors of prolonged operation time. The 3-year cancer specific survival (CSS) rate was 87.2% in our cohort. UB had no significant impact on cancer specific survival (P=0.435).@*CONCLUSION@#UB was an independent risk factor of prolonged RNU time, but did not significantly influence cancer specific survival of upper tract urothelial carcinoma patients.

Low power seven-step two-lobe holmium laser enucleation of the prostate technique for surgical treatment of benign prostatic hyperplasia / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the safety and efficacy of the seven-step two-lobe holmium laser enucleation of the prostate (HoLEP) technique with low power laser device, and to introduce the detailed operating procedures, key points, short-term outcomes of this modified HoLEP technique.@*METHODS@#From March 2016 to November 2017, 90 patients underwent HoLEP in Peking University Third Hospital. The patients were divided into two groups: high-power group (32 patients) were performed with traditional Gilling's three-lobe enucleation using high power (90 W) laser; Low-power group (58 patients) were performed with seven-step two-lobe enucleation using low power (40 W) laser. The main steps of the low power seven-step two-lobe HoLEP phase included: (1) The identification of the correct plane between adenoma and capsule at 5 and 7 o'clock laterally to the veru montanum; (2) The connection of the bilateral plane by making a adenoma incision at the proximal point of veru montanum; (3) The extension of the dorsal plane under the whole three lobes between adenoma and capsule towards the bladder neck; (4) The separation of the middle lobe from two lateral lobes by making two retrograde incisions separately from apex 5 and 7 o'clock towards the bladder neck; (5) The enucleation of the middle lobe adenoma by extending the dorsal plane through into the bladder; (6) The prevention of the apex mucosa by making a circle incision at the apex of the prostate; (7) The en-bloc enucleation of the two lateral lobe adenomas by extending the lateral and ventral plane between adenoma and capsule from 5 and 7 o'clock to 12 o'clock conjunction and through into the bladder.@*RESULTS@#The mean patient age was (66.25±5.37) years vs. (68.00±5.18) years; The mean body mass indexes were (24.13±4.06) kg/m2 vs. (24.57±3.50) kg/m2; The mean prostate specific antigen values were (3.23±2.47) μg/L vs. (6.00±6.09) μg/L; The average prostatic volumes evaluated by ultrasound was (49.03±20.63) mL vs. (67.55±36.97) mL. There was no significant difference between the two groups. Furthermore, there were no significant differences in terms of perioperative and follow up data, including operative time; enucleation efficiencies; hemoglobin decrease; blood sodium and potassiumthe change postoperatively; catheterization duration and hospital stay; the international prostate symptom scores and quality of life scores pre- and post-operatively. There was 1 transurethral resection of the prostate (TURP) conversion in high-power group and 1 transfusion in low-power group during the operations. The follow-up one month after operation showed no severe stress incontinence in both the groups, whereas 3 cases ejaculatory dysfunctions in high-power group versus 1 case in low-power group were observed; Other surgeryrelated complications included: 2 cases postoperative hemorrhage (Clavien II and Clavien IIIb) in high-power group, 2 cases postoperative temperature more than 38 °C (Clavien I) and 1 case dysuria following catheter removal (Clavien I) in low-power group.@*CONCLUSION@#Low power laser device can be applied safe and effectively for HoLEP procedure using the seven-step two-lobe HoLEP technique. The outcomes comparable with high power laser HoLEP can be achieved.

Influence of holmium laser and thulium laser enucleation of the prostate on erectile function / 中华男科学杂志

In recent years, holmium laser enucleation of the prostate (HoLEP) and thulium laser enucleation of the prostate (ThuLEP) have been widely used in the treatment of benign prostatic hyperplasia (BPH) because of their significant clinical effects, high safety, and low incidence of complications. With the improvement of living standards, BPH patients care about not only the improvement of lower-urinary-tract symptoms (LUTS) secondary to BPH but also that of sexual function, especially erectile function, after treatment. However, there are comparatively few studies about the effects of HoLEP and ThuLEP on erectile function and relevant opinions are quite controversial. Most studies reported that HoLEP and ThuLEP did not impair erectile function, but some showed that a few patients experienced a decrease of erectile function after operation. Before surgery, urologists should explain clearly to the patients the potential impact on sexual function, as mental factors may also induce erectile dysfunction. This study presents an overview of recent studies about the infuence of HoLEP and ThuLEP on erectile function.