A Nomogram for Predicting Prostate Cancer with Lymph Node Involvement in Robot-Assisted Radical Prostatectomy Era: A Retrospective Multicenter Cohort Study in Japan (The MSUG94 Group)

Development and internal validation of a nomogram predicting significant prostate cancer: Is it clinically applicable in low prevalent prostate cancer countries? A multicenter study

BACKGROUND

Accurately identifying aggressive prostate tumors and studying them as a separate outcome are urgently needed. Nomogram is a predictive tool using an algorithm, it has been widely applied in clinical practice to predict prognosis. We aimed to develop and internally validate a nomogram predicting clinically significant prostate cancer (csPCa).

METHODS

Data were retrieved from the records of the two main hospitals in Riyadh, during the period 2019-2022. Significant variables associated with csPCa cases were used to develop and internally validate a novel nomogram, utilizing the C index, and calibration curves. Decision curve analysis (DCA) was used to assess its clinical utility.

RESULTS

Prostate imaging reporting and data system (PI-RADS), smaller prostate volume, and prostate-specific antigen (PSA) > 10 ng/mL were significantly associated with the risk csPCa, respectively. The model developed by the nomogram showed an excellent accuracy for csPCa discrimination, as indicated by area under the curve (0.83), and calibration curves. DCA showed that our model was superior and surpassed all other models with a larger net benefit for various threshold probabilities. Based on our model, at a probability threshold of 30%, biopsying patients is the equivalent of a strategy that led to an absolute 5% reduction in the number of biopsies without missing any csPCa.

CONCLUSION

The developed nomogram consisting of PI-RAD, total PSA, and prostate volume showed a robust predictive capacity for csPCa before prostate biopsy that may be valuable for clinical judgment to prevent needless biopsy. Yet, the small percentage (5%) of yielded unnecessary biopsies that could be saved by using such a model, cast an important question on its merit and clinical applicability.

The Negative Impact of Inflammation-Related Parameters in Prostate Cancer after Robot-Assisted Radical Prostatectomy: A Retrospective Multicenter Cohort Study in Japan (the MSUG94 Group)

Background and Objectives: We aimed to examine the relationship between the inflammation-related parameters, such as the neutrophil-to-lymphocyte ratio (NLR), and the pathological findings and biochemical recurrence (BCR) in patients with prostate cancer (PCa) undergoing robot-assisted radical prostatectomy (RARP). Materials and Methods: A retrospective multicenter cohort study of patients with PCa who underwent RARP at 10 institutes in Japan was conducted. This study enrolled 3195 patients. We focused on patients undergoing RARP who underwent the preoperative measurement of their inflammation-related parameters and who did not receive any neo- or adjuvant therapy. Data on the pre- and postoperative variables for the enrolled patients were obtained. The primary endpoint of this study was the association between BCR and the inflammation-related parameters after RARP. The secondary endpoint was the association between the inflammation-related parameters and the pathological diagnosis of PCa. Results: Data from 2429 patients with PCa who met the study's eligibility criteria were analyzed. The median follow-up period was 25.1 months. The inflammation-related parameters were divided into two groups, and cutoff values were determined based on the receiver operating characteristics. There were no statistically significant differences in biochemical recurrence-free survival for any of the parameters. In the univariate analysis, the NLR was predictive of pathological T3 and lymphovascular invasion; however, there were no significant differences in the multivariate analysis. Conclusions: The inflammation-related parameters did not significantly affect the incidence of BCR, at least among patients with PCa who underwent RARP.

Development and validation of novel nomogram to identify the candidates for extended pelvic lymph node dissection for prostate cancer patients in the robotic era

OBJECTIVES

To determine candidates for extended pelvic lymph node dissection using a novel nomogram to assess the risk of lymph node invasion in Japanese prostate cancer patients in the robotic era.

METHODS

A total of 538 patients who underwent robot-assisted radical prostatectomy with extended pelvic lymph node dissection in three hospitals were retrospectively analyzed. Medical records were reviewed uniformly and the following data collected: prostate-specific antigen, age, clinical T stage, primary and secondary Gleason score at prostate biopsy, and percentage of positive core numbers. Finally, data from 434 patients were used for developing the nomogram and data from 104 patients were used for external validation.

RESULTS

Lymph node invasion was detected in 47 (11%) and 16 (15%) patients in the development and validation set, respectively. Based on multivariate analysis, prostate-specific antigen, clinical T stage ≥3, primary Gleason score, grade group 5, and percentage of positive cores were selected as variables to incorporate into the nomogram. The area under the curve values were 0.781 for the internal and 0.908 for the external validation, respectively.

CONCLUSIONS

The present nomogram can help urologists identify candidates for extended pelvic lymph node dissection concomitant with robot-assisted radical prostatectomy among patients with prostate cancer.