The association between the outcomes of extraperitoneal laparoscopic radical prostatectomy and the anthropometric measurements of the prostate by magnetic resonance imaging

Anatomic Factors Associated with Complications After Radical Prostatectomy: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

The role of anatomical factors in predicting outcomes after radical prostatectomy (RP) remains unclear. This review aims to evaluate the impact of various anatomical factors on the perioperative outcomes of patients undergoing RP for localized prostate cancer (PCa).

METHODS

A comprehensive literature search was conducted through January 2024 using the PubMed/Medline, Embase, and Web of Science databases. The Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were followed to identify eligible studies. Data were extracted and pooled for a meta-analysis, with outcomes including operative time, blood loss, transfusion rates, overall complications, and positive surgical margins (PSMs). Heterogeneity was assessed using Cochrane Q test, and subgroup analyses were conducted to explore the influence of surgical approach.

KEY FINDINGS AND LIMITATIONS

A total of 91 studies met our inclusion criteria. Among the anatomical factors, prostate volume (PV), prostate weight, and median lobe (ML) were suitable for the meta-analysis. Larger prostates were associated with increased operative time, blood loss, and complication rates, but with fewer PSMs (all p < 0.05). ML presence was not associated with a higher risk of complications. Heterogeneity was high across studies (Cochrane Q tests <0.05), reflecting inconsistent definitions and methods. In subgroup analyses, the open approach was associated with a longer operative time than robotic surgery for large prostates (p = 0.03) and a lower PSM rate (p < 0.001).

CONCLUSIONS AND CLINICAL IMPLICATIONS

Anatomical factors, particularly PV, play a significant role in RP outcomes. Larger prostates are associated with higher complication rates but fewer PSMs. Further research with standardized outcome measures is necessary to clarify these relationships and guide clinical decision-making.

PATIENT SUMMARY

In this study, we examined how a patient's individual anatomy might affect the results of prostate surgery for cancer. We found that larger prostates tend to lead to longer surgeries and increased blood loss, but these also have a lower risk of leaving cancer cells behind. These findings could help doctors in better planning surgeries and improving patient 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.

Value of three-dimensional visualization of preoperative prostatic magnetic resonance imaging based on measurements of anatomical structures in predicting positive surgical margin after radical prostatectomy

Background

Positive surgical margin (PSM) or apical positive surgical margin (APSM) is an established predictive factor of biochemical recurrence or disease progression in prostate cancer (PCa) patients after radical prostatectomy. Since there are limited usable magnetic resonance imaging (MRI)-based models, we sought to explore the role of three-dimensional (3D) visualization for preoperative MRI in the prediction of PSM or APSM.

Methods

From December 2016 to April 2022, 149 consecutive PCa patients who underwent radical prostatectomy were retrospectively selected from the Second Affiliated Hospital of Dalian Medical University. According to the presence of PSM or APSM, patients were divided into a PSM group (n=41) and a without PSM group (n=108) and into an APSM group (n=33) and a without APSM group (n=116). Twenty-one parameters, including prostate apical shape, PCa distance to the membranous urethra, and pubic angle, were measured on 3D visualization of MRI. The development of the nomogram models was built by the findings of multivariate logistic regression analysis for significant factors.

Results

To predict the probability of PSM, a longer PCa distance to the membranous urethra (OR=0.136, p=0.019) and the distance from the anterior peritoneum to the anterior border of the coccyx (work space AP, OR=0.240, p=0.030) were independent protective factors, while a type 3 prostate apical shape (OR=8.262, p=0.025) and larger pubic angle 2 (OR=5.303, p=0.029) were identified as independent risk factors. The nomogram model presented an area under the curve (AUC) of the receiver operating characteristic curve (ROC) of PSM of 0.777. In evaluating the incidence of APSM, we found that the distance to the membranous urethra (OR=0.135, p=0.014) was associated with a low risk of APSM, while larger pubic angle 1 (OR=4.666, p=0.043) was connected to a higher risk of APSM. The nomogram model showed that the AUC of APSM was 0.755.

Conclusion

As 3D visualization for preoperative MRI showed good performance in predicting PSM or APSM, the tool might be potentially valuable, which also needs to be validated by multicenter, large-scale, prospective studies.

Design, evaluation and comparison of endorectal coils for hybrid MR-PET imaging of the prostate

Prostate cancer is one of the most common cancers among men and its early detection is critical for its successful treatment. The use of multimodal imaging, such as MR-PET, is most advantageous as it is able to provide detailed information about the prostate. However, as the human prostate is flexible and can move into different positions under external conditions, it is important to localise the focused region-of-interest using both MRI and PET under identical circumstances. In this work, we designed five commonly used linear and quadrature radiofrequency surface coils suitable for hybrid MR-PET use in endorectal applications. Due to the endorectal design and the shielded PET insert, the outer face of the coils investigated was curved and the region to be imaged was outside the volume of the coil. The tilting angles of the coils were varied with respect to the main magnetic field direction. This was done to approximate the various positions from which the prostate could be imaged. The transmit efficiencies and safety excitation efficiencies from simulations, together with the signal-to-noise ratios from the MR images were calculated and analysed. Overall, it was found that the overlapped loops driven in quadrature were superior to the other types of coils we tested. In order to determine the effect of the different coil designs on PET, transmission scans were carried out, and it was observed that the differences between attenuation maps with and without the coils were negligible. The findings of this work can provide useful guidance for the integration of such coil designs into MR-PET hybrid systems in the future.

Localization of prostatic tumor's infection based on normalized mutual information MRI image segmentation

To investigate the effect of normalized mutual information (MRI) image segmentation in accurate localization of prostate cancer with infection and the role in disease treatment, the normalized mutual information method is used to measure the similarity of images, so as to select the maps. Then, the popular global weighted voting method and normalized mutual information method are applied to calculate the weights and carry out the label image fusion. The map selection method based on mutual information substantially completes the segmentation of the MRI image prostate. The prostate position is basically found on the 10 test images, and the positioning of the prostate organs is deviated in the worst case. In the case of poor multi-map segmentation, it usually happens when those are not well represented in the map. Because of the structural similarity of medical images, multi-atlas segmentation based on normalized mutual information method can be done. Using the prior information of atlas, the atlas label image can be selected. After fusion, the final segmentation of the test image can be completed, which has a high accuracy for the location of prostate cancer. This method can accurately delineate the target area in radiotherapy of prostate cancer and reduce the damage of rectum, bladder and other organs caused by radiotherapy. However, there are still some problems in this study, such as inadequate segmentation accuracy, long data processing time and so on. There is still a certain distance from practicality, and further research is needed.