Prediction of a positive surgical margin and biochemical recurrence after robot-assisted radical prostatectomy

A Clinically Feasible Electrode Array for 3D Intraoperative Electrical Impedance Tomography-Based Surgical Margin Assessment in Robot-Assisted Radical Prostatectomy

OBJECTIVE

A novel small form factor circular electrode array was designed specifically for electrical impedance tomography (EIT) based assessment of surgical margins during robot assisted radical prostatectomy (RARP).

METHODS

The electrode array consists of 33 gold-plated electrodes arranged within a 9.5 mm diameter circular footprint on the end of a surgical probe that can be introduced through a standard 12 mm laparoscopic port used during RARP. The electrode array contains 8 larger, low-contact impedance outer electrodes dedicated for current drive and an internal grid of 25 smaller electrodes for simultaneous voltage measurement. Separating electrode geometry by function is designed to improve current delivery, speed, and resolution while reducing hardware requirements.

RESULTS

Simulations demonstrated that 1 mm diameter hemispherical prostate cancer inclusions could be localized within regions of adipose and benign prostate tissue; 1.5 mm diameter inclusions were required for localization within muscle tissue. A 2.38 mm diameter aluminum rod in 0.2 S/m saline could be localized throughout the imaging domain with a position error of less than 2.5 mm for depths from the electrode array surface of up to 1.7 mm. Ex vivo tissue experiments with a bovine model demonstrate visual congruence of muscle and adipose tissue locations between the sample and reconstructed images.

CONCLUSION

Simulation and experimental results indicate good detection and location of inclusions.

SIGNIFICANCE

These results suggest the proposed electrode array design can provide sufficient accuracy in the detection and localization of prostate cancer against clinically relevant background tissues for use during RARP.

Overall Survival and Cancer-Specific Mortality in Patients with Prostate Cancer Undergoing Definitive Therapies: A Narrative Review

The overall survival (OS) of patients with prostate cancer (PCa) who receive locally definitive therapy is generally better than that of patients who do not receive definitive therapy. There is no difference in the incidence of local recurrence or distant metastasis between treatment modalities. Because the prognosis of PCa is relatively good, many studies have focused on quality of life after treatment as an endpoint. However, a limited number of patients develop biochemical recurrence after definitive treatment for PCa and subsequently develop distant metastasis or die from PCa. Therefore, we believe that preventing local recurrence and distant metastasis and prolonging the OS should be emphasized when selecting a treatment modality for PCa. In this review, the significance and usefulness of radical prostatectomy and radiation therapy as the main modalities of definitive therapies for local PCa and locally advanced PCa were evaluated, as well as the outcomes of OS and PCa-specific mortality and the treatment options after biochemical recurrence to improve the oncological outcomes.

Development of preoperative nomograms to predict the risk of overall and multifocal positive surgical margin after radical prostatectomy

OBJECTIVE

To develop preoperative nomograms using risk factors based on clinicopathological and MRI for predicting the risk of positive surgical margin (PSM) after radical prostatectomy (RP).

PATIENTS AND METHODS

This study retrospectively enrolled patients who underwent prostate MRI before RP at our center between January 2015 and November 2022. Preoperative clinicopathological factors and MRI-based features were recorded for analysis. The presence of PSM (overall PSM [oPSM]) at pathology and the multifocality of PSM (mPSM) were evaluated. LASSO regression was employed for variable selection. For the final model construction, logistic regression was applied combined with the bootstrap method for internal verification. The risk probability of individual patients was visualized using a nomogram.

RESULTS

In all, 259 patients were included in this study, and 76 (29.3%) patients had PSM, including 40 patients with mPSM. Final multivariate logistic regression revealed that the independent risk factors for oPSM were tumor diameter, frank extraprostatic extension, and annual surgery volume (all p < 0.05), and the nomogram for oPSM reached an area under the curve (AUC) of 0.717 in development and 0.716 in internal verification. The independent risk factors for mPSM included the percentage of positive cores, tumor diameter, apex depth, and annual surgery volume (all p < 0.05), and the AUC of the nomogram for mPSM was 0.790 in both development and internal verification. The calibration curve analysis showed that these nomograms were well-calibrated for both oPSM and mPSM.

CONCLUSIONS

The proposed nomograms showed good performance and were feasible in predicting oPSM and mPSM, which might facilitate more individualized management of prostate cancer patients who are candidates for surgery.

Clinical risk prediction model and external validation of positive surgical margin in laparoscopic radical prostatectomy based on MRI lesion location

OBJECTIVE

To clarify the composition of lesions in different magnetic resonance imaging (MRI) partitions of positive surgical margins (PSM) after laparoscopic radical prostatectomy, explore the influence of lesion location on PSM, and construct a clinical prediction model to predict the risk of PSM.

MATERIALS AND METHODS

This retrospective cohort study included 309 patients who underwent laparoscopic radical prostatectomy from 2018 to 2021 in our center was performed. 129 patients who met the same criteria from January to September 2022 were external validation cohorts.

RESULTS

The incidence of PSM in transition zone (TZ) lesions was higher than that in peripheral zone (PZ) lesions. The incidence of PSM in the middle PZ was lower than that in other regions. Prostate specific antigen (PSA), clinical T-stage, the number of positive cores, international society of urological pathology (ISUP) grade (biopsy), MRI lesion location, extracapsular extension, seminal vesicle invasion (SVI), pseudo-capsule invasion (PCI), long diameter of lesions, lesion volume, lesion volume ratio, PSA density were related to PSM. MRI lesion location and PCI were independent risk factors for PSM. Least absolute shrinkage and selection operator (LASSO) regression was used to construct a clinical prediction model for PSM, including five variables: the number of positive cores, SVI, MRI lesion location, long diameter of lesions, and PSA.

CONCLUSION

The positive rate of surgical margin in middle PZ was significantly lower than that in other regions, and MRI lesion location was an independent risk factor for PSM.

Research on the mean maximum Young's modulus value as a new diagnostic parameter for prostate cancer

Ultrasound-based shear wave elastography (SWE) can non-invasively assess prostate tissue stiffness for the diagnosis of prostate cancer (PCa). So far, there is no widely recognized standard for the detection process and calculation method of Young's modulus value in transrectal SWE ultrasound imaging (TSWEUI). In our study, the mean maximum Young's modulus value (m-Emax) of the maximum cross-section of prostate is obtained by calculating the mean of 12 measured Emax in the four quadrants. This retrospective study included 209 suspected malignant prostate disease patients with pathological results in our hospital. Among the 209 patients, 75 patients completed TSWEUI, and 63 of the 75 patients completed magnetic resonance imaging (MRI). The area under the receiver operating characteristic (ROC) curve (AUC) of 75 patients for m-Emax was 0.754. The prostate volume, prostate-specific antigen, and m-Emax were used to develop a nomogram (AUC = 0.868). The nomogram could effectively predict the probability of PCa, thereby reducing the needle biopsy rate for diagnosing PCa. The AUC of 63 patients was not statistically different between m-Emax (AUC = 0.717) and MRI (AUC = 0.787) (P = 0.361). These indicate that m-Emax can be used as an innovative parameter in TSWEUI to diagnosis PCa. TSWEUI is more cost-effective than MRI in diagnosing PCa.

Risk classification system using the detailed positive surgical margin status for predicting biochemical recurrence after robot-assisted radical prostatectomy

AIM

This study aimed to evaluate the risk classification system using the detailed positive surgical margin (PSM) status to predict biochemical recurrence (BCR) after robot-assisted radical prostatectomy (RARP).

METHODS

We retrospectively analyzed 427 patients who underwent RARP between January 2016 and March 2020. We investigated risk factors for BCR using univariate and multivariate Cox proportional hazard regression models. The biochemical recurrence-free survival (BRFS) rate was assessed using the Kaplan-Meier method.

RESULTS

The median follow-up period was 43.4 months and 99 patients developed BCR. In the multivariate analysis, maximum PSM length > 5.0 mm and the International Society of Urological Pathology grade group (ISUP GG) at the PSM ≥3 were predictive factors for BCR in patients with a PSM. In the multivariate analysis, these factors were also independent predictive factors in the overall study population, including patients without a PSM. We classified the patients into four groups using these factors and found that the 1-year BRFS rates in the negative surgical margin (NSM) group, low-risk group (PSM and neither factor), intermediate-risk group (either factor), and high-risk group (both factors) were 94.9%, 94.5%, 83.1%, and 52.9%, respectively. The low-risk group showed similar BRFS to the NSM group (p = 0.985), while the high-risk group had significantly worse BRFS than the other groups (p < 0.001).

CONCLUSION

Maximum PSM length > 5.0 mm and ISUP GG at the PSM ≥3 were independent predictive factors for BCR after RARP. Risk classification for BCR using these factors is considered to be useful and might help urologists decide on additional treatment after RARP.

Imaging classification of prostate cancer with extracapsular extension and its impact on positive surgical margins after laparoscopic radical prostatectomy

Abstract

To explore the impact of different imaging classifications of prostate cancer (PCa) with extracapsular extension (EPE) on positive surgical margins (PSM) after laparoscopic radical prostatectomy.

Methods

Clinical data were collected for 114 patients with stage PT3a PCa admitted to Ningbo Yinzhou No. 2 Hospital from September 2019 to August 2023. Radiologists classified the EPE imaging of PCa into Type I, Type II, and Type III. A chi-square test or t-test was employed to analyze the factors related to PSM. Multivariate regression analysis was conducted to determine the factors associated with PSM. Receiver operating characteristic curve analysis was used to calculate the area under the curve and evaluate the diagnostic performance of our model. Clinical decision curve analysis was performed to assess the clinical net benefit of EPE imaging classification, biopsy grade group (GG), and combined model.

Results

Among the 114 patients, 58 had PSM, and 56 had negative surgical margins. Multivariate analysis showed that EPE imaging classification and biopsy GG were risk factors for PSM after laparoscopic radical prostatectomy. The areas under the curve for EPE imaging classification and biopsy GG were 0.677 and 0.712, respectively. The difference in predicting PSM between EPE imaging classification and biopsy GG was not statistically significant (P>0.05). However, when used in combination, the diagnostic efficiency significantly improved, with an increase in the area under the curve to 0.795 (P<0.05). The clinical decision curve analysis revealed that the clinical net benefit of the combined model was significantly higher than that of EPE imaging classification and biopsy GG.

Conclusions

EPE imaging classification and biopsy GG were associated with PSM after laparoscopic radical prostatectomy, and their combination can significantly improve the accuracy of predicting PSM.

CCT6A dysregulation in surgical prostate cancer patients: association with disease features, treatment information, and prognosis

OBJECTIVE

Chaperonin-containing tailless complex polypeptide 1 subunit 6A (CCT6A) involves several solid cancers' development and progression, while its clinical utility in prostate cancer management is rarely revealed. Consequently, the present study intended to investigate the linkage of CCT6A with disease features, treatment information, and prognosis of surgical prostate cancer patients.

METHODS

CCT6A in 220 surgical prostate cancer patients was determined via immunohistochemistry. Additionally, survival analyses on data from the public databases were performed to validate the prognostic value of CCT6A further.

RESULTS

CCT6A expression was upregulated in tumor tissue than in adjacent tissue (P < 0.001). Increased CCT6A was related to elevated Gleason score (P < 0.001) and pathological T stage (P = 0.029). CCT6A was increased in patients with positive surgical margin status (vs. negative) (P = 0.029) and patients with adjuvant external-beam radiation therapy (vs. no) (P = 0.001). Concerning the prognostic value, high tumor CCT6A was linked with shortened disease-free survival (DFS) (P = 0.009), which was also validated through further Cox's proportional hazard regression model analyses (hazard ratio: 2.695, 95% CI: 1.086-6.683, P = 0.032), whereas CCT6A was not correlated with overall survival (OS) (P > 0.050). Additionally, the Gene Expression Profiling Interactive Analysis database indicated that high tumor CCT6A was related to shortened DFS (P = 0.036), but it was not associated with OS (P > 0.050); meanwhile, the Human Protein Atlas database suggested that high tumor CCT6A was linked with reduced OS (P = 0.048).

CONCLUSION

Tumor CCT6A high expression correlates with the elevated Gleason score, pathological T stage, and shortened DFS in surgical prostate cancer patients.

Risk Biomarkers for Biochemical Recurrence after Radical Prostatectomy for Prostate Cancer Using Clinical and MRI-Derived Semantic Features

OBJECTIVES

This study aimed to assess the impact of the covariates derived from a predictive model for detecting extracapsular extension on pathology (pECE+) on biochemical recurrence-free survival (BCRFS) within 4 years after robotic-assisted radical prostatectomy (RARP).

METHODS

Retrospective data analysis was conducted from a single center between 2015 and 2022. Variables under consideration included prostate-specific antigen (PSA) levels, patient age, prostate volume, MRI semantic features, and Grade Group (GG). We also assessed the influence of pECE+ and positive surgical margins on BCRFS. To attain these goals, we used the Kaplan-Meier survival function and the multivariable Cox regression model. Additionally, we analyzed the MRI features on BCR (biochemical recurrence) in low/intermediate risk patients.

RESULTS

A total of 177 participants with a follow-up exceeding 6 months post-RARP were included. The 1-year, 2-year, and 4-year risks of BCR after radical prostatectomy were 5%, 13%, and 21%, respectively. The non-parametric approach for the survival analysis showed that adverse MRI features such as macroscopic ECE on MRI (mECE+), capsular disruption, high tumor capsular contact length (TCCL), GG ≥ 4, positive surgical margins (PSM), and pECE+ on pathology were risk factors for BCR. In low/intermediate-risk patients (pECE- and GG < 4), the presence of adverse MRI features has been shown to increase the risk of BCR.

CONCLUSIONS

The study highlights the importance of incorporating predictive MRI features for detecting extracapsular extension pre-surgery in influencing early outcomes and clinical decision making; mECE+, TCCL, capsular disruption, and GG ≥ 4 based on pre-surgical biopsy were independent prognostic factors for early BCR. The presence of adverse features on MRI can assist in identifying low/intermediate-risk patients who will benefit from closer monitoring.

Short-term prognosis of low-risk prostate cancer patients is favorable despite the presence of pathological prognostic factors: a retrospective study

BACKGROUND

Prostate cancer patients with pathological prognostic factors have a poor prognosis, but it is unclear whether pathological prognostic factors are associated with prognosis limited to low-risk patients with good prognosis according to NCCN guidelines. The present study examined whether prognosis is influenced by pathological prognostic factors using radical prostatectomy (RP) specimens from low-risk patients.

METHODS

We evaluated diagnostic accuracy by examining biochemical recurrence (BCR)-free survival with respect to clinical and pathological prognostic factors in 419 all-risk patients who underwent RP. Clinical prognostic factors included age, prostate-specific antigen (PSA) levels, PSA density, and risk stratification, while pathological prognostic factors included grade group, lymphovascular space invasion, extraprostatic extension, surgical margins, seminal vesicle invasion, intraductal carcinoma of the prostate (IDCP), and pT. In a subsequent analysis restricted to 104 low-risk patients, survival curves were estimated for pathological prognostic factors using the Kaplan-Meier method and compared using log-rank and generalized Wilcoxon tests.

RESULTS

In the overall risk analysis, the presence of pathological prognostic factors significantly shortened BCR-free survival (p < 0.05). Univariable analysis revealed that PSA density, risk categories, and pathological prognostic factors were significantly associated with BCR-free survival, although age and PSA were not. In multivariable analysis, age, risk categories, grade group, IDCP, and pT significantly predicted BCR-free survival (p < 0.05). Conversely, no statistically significant differences were found for any pathological prognostic factors in low-risk patients.

CONCLUSIONS

In low-risk patients, pathological prognostic factors did not affect BCR-free survival, which suggests that additional treatment may be unnecessary even if pathological prognostic factors are observed in low-risk patients with RP.

Quantitative Dynamic Contrast-Enhanced Magnetic Resonance Parameters Could Predict International Society of Urological Pathology Risk Groups of Prostate Cancers on Radical Prostatectomy

BACKGROUND

The International Society of Urological Pathology (ISUP) grade and positive surgical margins (PSMs) after radical prostatectomy (RP) may reflect the prognosis of prostate cancer (PCa) patients. This study aimed to investigate whether DCE-MRI parameters (i.e., Ktrans, kep, and IAUC) could predict ISUP grade and PSMs after RP.

METHOD

Forty-five PCa patients underwent preoperative DCE-MRI. The clinical characteristics and DCE-MRI parameters of the 45 patients were compared between the low- and high-risk (i.e., ISUP grades III-V) groups and between patients with or without PSMs after RP. Multivariate logistic regression analysis was used to identify the significant predictors of placement in the high-risk group and PSMs.

RESULTS

The DCE parameter Ktrans-max was significantly higher in the high-risk group than in the low-risk group (p = 0.028) and was also a significant predictor of placement in the high-risk group (odds ratio [OR] = 1.032, 95% confidence interval [CI] = 1.005-1.060, p = 0.021). Patients with PSMs had significantly higher prostate-specific antigen (PSA) titers, positive biopsy core percentages, Ktrans-max, kep-median, and kep-max than others (all p < 0.05). Of these, positive biopsy core percentage (OR = 1.035, 95% CI = 1.003-1.068, p = 0.032) and kep-max (OR = 1.078, 95% CI = 1.012-1.148, p = 0.020) were significant predictors of PSMs.

CONCLUSION

Preoperative DCE-MRI parameters, specifically Ktrans-max and kep-max, could potentially serve as preoperative imaging biomarkers for postoperative PCa prognosis based on their predictability of PCa risk group and PSM on RP, respectively.

Experience with an innovative surgical approach: 321 cases modified extraperitoneal single-incision robot-assisted laparoscopic radical prostatectomy without dedicated PORT based on Da Vinci SI system

To summarize surgical experiences with a new modified technique involving extraperitoneal single-incision robot-assisted laparoscopic radical prostatectomy based on Da Vinci SI system by reviewing case data, including follow ups, and to evaluate the safety and clinical efficacy of the surgical procedure. The case data from December 2020 to September 2022 of 321 patients undergoing modified single incision (without dedicated PORT) robotic-assisted laparoscopic radical prostatectomy via an extraperitoneal approach were reviewed. All procedures were performed by the same surgeon at our center. Perioperative data and postoperative urinary control, tumor control, and erectile function recovery were assessed. The immediate, 3-months, 6-months, 12-months, 18-months and 24-months complete urinary control rates were 34.3%, 56.6%, 79.7%, 85.7%, 89.6% and 90.7%, respectively; the 3-months, 6-months, 12-months, 18-months and 24-months biochemical recurrence rates were 3.4%, 5.2%, 9.1%, 21.7% and 30.2%, respectively; and for those with normal preoperative erectile function, the 3-months, 6-months, 12-months, 18-months and 24-months postoperative erectile function recovery rates were 52.2%, 60.0%, 70.7%, 72.2% and 73.9%, respectively. The new modified technique involving extraperitoneal single-incision robotic-assisted laparoscopic radical prostatectomy is safe and feasible. This technique has satisfactory surgical results, and this new method results in satisfactory urinary control, tumor control and recovery of erectile function. In addition, this new method is not limited to specific dedicated access devices, which facilitates its application.

Prognostic differences among the positive surgical margin locations following robot-assisted radical prostatectomy in a large Japanese cohort (the MSUG94 group)

BACKGROUND

To investigate whether subgroups of prostate cancer patients, stratified by positive surgical margin locations, have different oncological outcomes following robot-assisted radical prostatectomy.

METHODS

A retrospective multicenter cohort study in prostate cancer patients undergoing robot-assisted radical prostatectomy was conducted at 10 institutions in Japan. Pre- and post-operative outcomes were collected from enrolled patients. Biochemical recurrence and clinical and pathological variables were evaluated among subgroups with different positive surgical margin locations.

RESULTS

A total of 3195 patients enrolled in this study. Data from 2667 patients (70.1% [N = 1869] with negative surgical margins and 29.9% [N = 798] with positive surgical margins based on robot-assisted radical prostatectomy specimens) were analyzed. The median follow-up period was 25.0 months. The numbers of patients with apex-only, middle-only, bladder-neck-only, seminal-vesicle-only and multifocal positive surgical margins were 401, 175, 159, 31 and 32, respectively. In the multivariate analysis, PSA level at surgery, pathological Gleason score based on robot-assisted radical prostatectomy specimens, pathological T stage, pathological N stage and surgical margin status were independent risk factors significantly associated with biochemical recurrence-free survival. Patients undergoing robot-assisted radical prostatectomy with multifocal positive surgical margins and seminal-vesicle-only positive surgical margins were associated with worse biochemical recurrence-free survival than those with apex-only, middle-only and bladder-neck-only positive surgical margins. Patients undergoing robot-assisted radical prostatectomy with apex-only positive surgical margins, the most frequent positive surgical margin location, were associated with more favorable biochemical recurrence-free survival that those with middle-only and bladder-neck-only positive surgical margins. The study limitations included the lack of central pathological specimen evaluation.

CONCLUSIONS

Although positive surgical margin at any locations is a biochemical recurrence risk factor after robot-assisted radical prostatectomy, positive surgical margin location status should be considered to accurately stratify the biochemical recurrence risk after robot-assisted radical prostatectomy.

Effects of nerve-sparing procedures on surgical margins after robot-assisted radical prostatectomy

BACKGROUND

Nerve-sparing (NS) techniques could potentially increase positive surgical margins after robot-assisted radical prostatectomy (RARP). Nevertheless, the available studies have revealed ambiguous results among distinct groups. This study purposed to clarify the details of NS techniques to accurately estimate their influence on margin status.

METHODS

We studied RARPs performed by one surgeon from 2010 to 2018. Surgical margins were evaluated by the laterality and levels of NS techniques in site-specific prostate lobes. The multivariable analysis evaluated the effects of nerve-sparing procedures, combined with other covariate factors, on margin status.

RESULTS

Overall, 419 RARPs involving 838 prostate lobes were analyzed. Notably, 181 patients (43.4%) had pT2-stage, and 236 (56.6%) had pT3-stage cancer. The PSM rates for patients who underwent unilateral, bilateral, and non NS procedures were 30.3%, 28.8%, and 50%, respectively ( p = 0.233) or in stratification by pT2 ( p = 0.584) and pT3 ( p = 0.116) stage. The posterolateral PSM rates among site-specific prostate lobes were 10.9%, 22.4%, and 18.9% for complete, partial, and non NS techniques, respectively ( p = 0.001). The partial NS group revealed a significant increase in PSM rate compared with the complete NS (OR 2.187, 95% CI: 1.19-4.03) and non NS (OR 2.237, 95% CI: 1.01-4.93) groups in site-specific prostate lobes.

CONCLUSION

Partial NS procedures have a potential risk of increasing the positive surgical margins rate than complete and non NS procedures do. Therefore, correct case selection is required before performing partial NS techniques.

Short-term oncological and surgical outcomes of robot-assisted radical prostatectomy: A retrospective multicenter cohort study in Japan (the MSUG94 group)

INTRODUCTION

We evaluated oncological outcomes of patients undergoing robot-assisted radical prostatectomy (RARP) for prostate cancer (PCa) and their perioperative complications in Japan. We investigated clinical and pathological covariates to predict biochemical recurrence (BCR) after RARP.

METHODS

A retrospective multicenter cohort study was conducted in RARP patients with PCa at 10 institutions in Japan. Pre- and postoperative covariates were collected from enrolled patients. The primary endpoint was defined as biochemical recurrence-free survival (BRFS). Additionally, the association between BCR and clinicopathological covariates was determined.

RESULTS

We enrolled 2670 patients in this study. The median follow-up period was 26.0 months. RARP-related perioperative complications were identified in 198 patients (7.4%), including 69 patients (2.6%) with grade 3/4 complications according to the Clavien-Dindo classification. The 2-year BRFS was 88.0%. Using the Kaplan-Meier method, initial prostate-specific antigen (PSA) level of ≤7.6 ng/mL, biopsy and pathological Gleason score (GS) of ≤7, clinical and pathological T1/2, and low/intermediate risks according to the National Comprehensive Cancer Network risk classification, and negative surgical margin status had significant BRFS than their counterparts. In multivariate analysis, initial PSA, biopsy and pathological GS, clinical and pathological T stage, and surgical margin status significantly correlated with BCR after RARP.

CONCLUSION

In this study, RARP achieved a lower incidence of perioperative complications than other studies.