Assessment of low prostate weight as a determinant of a higher positive margin rate after laparoscopic radical prostatectomy: a prospective pathologic study of 1,500 cases

Effects of Bony Pelvic and Prostate Dimensions on Surgical Difficulty of Robot-Assisted Radical Prostatectomy: An Original Study and Meta-analysis

BACKGROUND

Due to the deep location of the prostate within the pelvic cavity, procedures of robot-assisted radical prostatectomy (RARP) might be challenged by the prostate size and the limited pelvic cavity space. This study aimed to investigate the roles of bony pelvic and prostate dimensions in RARP procedures by an original study coupled with a meta-analysis.

METHODS

In the original study, patients undergoing multiport RARP between 2021 and 2022 were consecutively assessed. The associations of anatomic features with operative time (OT), estimated blood loss (EBL), and positive surgical margin (PSM) were evaluated using linear and logistic regression analyses as well as restricted cubic spline (RCS) analysis. Based on machine-learning algorithms, this study established predictive models for surgical difficulty and interpreted the model using SHapley Additive exPlanation (SHAP). In the meta-analysis, three databases were searched for eligible studies. Quantitative syntheses were subsequently performed.

RESULTS

Overall, 219 patients were enrolled in the original study. Prostate volume (PV) and the prostate volume-to-pelvic cavity index (PCI) ratio (PV-to-PCI ratio) were significantly associated with longer OT (P < 0.05). In the RCS models, U-shaped associations were observed between the prostate anteroposterior diameter (PAD) and OT, and between the prostate height (PH) and EBL, and an L-shaped association was observed between the anteroposterior diameter of the pelvic inlet (API) and EBL. The XGBoost model was superior to the logistic regression model in predicting prolonged OT. The meta-analysis demonstrated that greater PV was significantly associated with longer OT (β = 0.20; 95% confidence interval [CI] 0.12-0.27; odds ratio [OR] = 1.05; 95% CI 1.00-1.11), and a smaller PV could increase the risk of PSM (OR = 0.82; 95% CI 0.77-0.88).

CONCLUSIONS

A large prostate within a narrow and deep pelvis might suggest increased surgical difficulty of RARP. The size of the pelvic inlet also had a great impact on RARP. For PAD and PH, there seemed to be an optimal range with the lowest surgical difficulty. Machine-learning models based on the XGBoost algorithm could be successfully applied to predict the surgical difficulty of RARP.

The association between prostate weight and positive surgical margins in prostate cancer: A meta-analysis

There have been some conflicting claims whether larger prostate weight (PW) reduces the risk of positive surgical margins (PSMs). This study aims to examine the associations between PW and PSMs. PubMed, Web of Science and Cochrane library were systematically retrieved. Relative risks (RRs) and the corresponding 95% confidence intervals (CIs) were synthesised utilising random-effect models. Ultimately, 22 cohort studies met criteria were enrolled in this meta-analysis, of which 18 studies reporting the RR of the highest VS lowest category of PW yielded the combined RR of PSMs of 0.61 (95% CI 0.50-0.74). Subgroup analysis showed that geographic region and surgical modalities were considered as potential confounders of influence of PW on PSMs. The nonlinear dose-response relationship demonstrated that PSM risk decreased by 1% (RR = 0.99, 95% CI, 0.98-0.99) for every one gram increment in PW. This study suggests PW has a negative association with risk of PSMs, and having a appropriate PW is very important.

Difference between actual vs. pathology prostate weight in TURP and radical robotic-assisted prostatectomy specimen

INTRODUCTION

To investigate and highlight the effect of formaldehyde induced weight reduction in transurethral resection of prostate (TURP) and radical robotically-assisted prostatectomy (RALP) specimen as a result of standard chemical fixation.

MATERIALS AND METHODS

51 patients were recruited from January 2013 to June 2013 who either underwent a TURP (n=26) or RALP (n=25). Data was collected prospectively by the operating surgeon who measured the native, unfixed histology specimen directly after operation. The specimens were fixed in 10% Formaldehyde Solution BP and sent to the pathology laboratory where after sufficient fixation period was re-weighed.

RESULTS

Overall mean age 64.78 years, TURP mean age 68.31 years RALP mean age 61.12 years. We found that the overall prostatic specimen (n=51) weight loss after fixation was a mean of 11.20% (3.78 grams) (p ≤ 0.0001). Subgroup analysis of the native TURP chips mean weight was 16.15 grams and formalin treated mean weight was 14.00 grams (p ≤ 0.0001). Therefore, TURP chips had a mean of 13.32 % (2.15 grams) weight loss during chemical fixation. RALP subgroup unfixed specimen mean weight was 52.08 grams and formalin treated mean weight was 42.60 grams (p ≤ 0.0001), a 19.32 % (9.48 grams) mean weight reduction.

CONCLUSION

It has not been known that prostatic chips and whole human radical prostatectomy specimen undergo a significant weight reduction. The practical significance of the accurate prostate weight in patient management may be limited, however, it is agreed that this should be recorded correctly, as data is potential interest for research purposes and vital for precise documentation.

Robotic Prostatectomy Has a Superior Outcome in Larger Prostates and PSA Density Is a Strong Predictor of Biochemical Recurrence

Objectives. The aims of this study were to compare the outcomes of robotic assisted laparoscopic prostatectomy (RALP) between patients who had larger (≥75 g) and smaller (<75 g) prostates and to evaluate the performance of PSA density (PSAD) in determining the oncological outcome of surgery. Methods and Materials. 344 patients who underwent RALP at a single institution were included in the study. Preoperative risk factors and postoperative, oncological outcomes, erectile function, and continence status were recorded prospectively. Results. During a mean follow-up of 20 months, biochemical recurrence (PSA > 0.2) was observed in 15 patients (4.3%). Prostate size ≥75 g was associated with lower Gleason score on final pathology (P = 0.004) and lower pathological stage (P = 0.02) but an increased length of hospital stay (P = 0.05). PSAD on binary logistic regression independently predicted biochemical recurrence (BCR) when defined as postoperative PSA >0.1 (P = 0.001) and PSA >0.2 (P = 0.039). In both instances PSA was no longer a significant independent predictor. Conclusions. RALP in large prostates (≥75 g, <150 g) is as safe as RALP in smaller prostates and is associated with a lower pathological grade and stage. Higher PSAD is independently associated with BCR and is superior to PSA as a predictor of BCR after RALP.

International Society of Urological Pathology (ISUP) Consensus Conference on Handling and Staging of Radical Prostatectomy Specimens. Working group 1: specimen handling

The 2009 International Society of Urological Pathology Consensus Conference in Boston made recommendations regarding the standardization of pathology reporting of radical prostatectomy specimens. Issues relating to the handling and processing of radical prostatectomy specimens were coordinated by working group 1. Most uropathologists followed similar procedures for fixation of radical prostatectomy specimens, with 51% of respondents transporting tissue in formalin. There was also consensus that the prostate weight without the seminal vesicles should be recorded. There was consensus that the surface of the prostate should be painted. It was agreed that both the prostate apex and base should be examined by the cone method with sagittal sectioning of the tissue sample. There was consensus that the gland should be fully fixed before sectioning. Both partial and complete embedding of prostates was considered to be acceptable as long as the method of partial embedding is stated. No consensus was determined regarding the necessity of weighing and measuring the length of the seminal vesicles, the preparation of whole mounts rather than standardized blocks and the methodology for sampling of fresh tissue for research purposes, and it was agreed that these should be left to the discretion of the working pathologist.