Biochemical recurrence‐free conditional probability after radical prostatectomy: A dynamic prognosis

Prediction of biochemical recurrence after laparoscopic radical prostatectomy

BACKGROUND

Radical prostatectomy (RP) has been considered primary treatment for localized prostate cancer. Biochemical recurrence (BCR) occur approximately 20-30% in five year after RP. We aim to develop a novel nomogram to predict BCR-free survival (BCRFS) and performed external validation using a validation cohort that may help clinicians to make better decision for tailoring adjuvant treatment to specific group of patients.

MATERIALS AND METHODS

This retrospective cohort study included 370 localized and regional prostate cancer patients who underwent laparoscopic radical prostatectomy (LRP) in Songklanagarind hospital between January 2010 and December 2019, the patients were divided into two groups (primary cohort and validation cohort). BCR-free survival was created using Kaplan-Meier curve. Predictive factors for BCR were identified with univariable and multivariable analysis using Cox proportional hazards model. Predictive nomogram was created using these identified factors and developed for the prediction of biochemical recurrence free survival (BCRFS) at 1 and 5 years after LRP.

RESULTS

For primary Songklanagarind cohort, BCR was found in 105 patients (44.7%). Overall 1-year BCR-free survival was 52.8%, and 5-year BCR-free survival was 45.7% with median time to BCR of 18.1 months. Multivariable analysis identified unfavorable factor to BCRRF which are high initial serum PSA (> 20) (p < 0.001; HR 3.2), ISUP Gleason grade group > = 3 (p 0.033; HR 2.2), positive surgical margins (p 0.046; HR 1.5), and seminal vesicle involvement (p < 0.001; HR 5.2) and using for develop a novel nomogram to predict BCR. Concordance index 0.78.

CONCLUSION

Prostate cancer patients with unfavorable factors, including high initial PSA (> 20), ISUP Gleason grade group > = 3, positive margin and extra-prostatic tumor extension are considered high risks and independent predictors of biochemical recurrence. This predictive models could potentially improve the 1 and 5-year BCR prediction after RP, according to the study's findings and will aid medical professionals in achieving the goal of clinical prediction and creating a proper management for the localized treatment of prostate cancer underwent laparoscopic radical prostatectomy.

Novel nomogram to predict biochemical recurrence-free survival after radical prostatectomy

PURPOSE

Conditional survival represents the probability of subsequent survival given that patients have already survived a certain length of time. Several models predict biochemical recurrence (BCR) after radical prostatectomy. However, none of them include postoperative prostate-specific antigen (PSA). We aimed to analyze BCR-free survival evolution over time and develop a nomogram incorporating the postoperative PSA value to predict BCR-free survival.

MATERIAL AND METHODS

We included patients treated with robot-assisted radical prostatectomy (RARP) for prostate cancer between 2009 and 2021 and calculated conditional survival. Cox proportional hazard regression analysis was used to assess the predictive variables of BCR. We developed a nomogram predicting BCR-free survival three and five years after RARP. We used c-index and decision curve analyses to compare the nomogram with the Cancer of the Prostate Risk Assessment post-Surgical (CAPRA-S) score.

RESULTS

We included 718 patients. The overall 3- and 5-year BCR-free survival rates were 85.1% and 75.7%, respectively. The 5-year BCR-free survival rates increased to 78.9%, 82.9%, 85.2%, and 84.7% for patients surviving 1, 2, 3, and 4 years without BCR, respectively. We developed a nomogram including the pathological Gleason score and T stage, positive surgical margin, PSA ≥ 0.05 ng/mL at one year, and lymph node involvement to predict BCR at 3 and 5 years postoperatively. Our nomogram presented a higher c-index (0.89) than the CAPRA-S score (0.78; p = 0.001) and a positive net benefit at 3 and 5 years postoperatively in the decision curve analyses.

CONCLUSION

The 5-year conditional BCR-free survival increased with survival without BCR. The developed nomogram significantly improved the accuracy in predicting BCR-free survival after RARP.

A novel nomogram provides improved accuracy for predicting biochemical recurrence after radical prostatectomy

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.

Conditional biochemical recurrence-free survival after radical prostatectomy in patients with high-risk prostate cancer

Background

Conditional survival is defined as the likelihood of subsequent survival given the precondition of having already survived a certain length of time. Most analyses of conditional survival in prostate cancer are not clinically applicable because they do not analyze outcomes conditioned on the durability of cure after treatment. We evaluated the conditional probability of biochemical recurrence (BCR)-free survival (C-BCRFS) after radical prostatectomy (RP) for prostate cancer according to the National Comprehensive Cancer Network risk classification and prognostic factors in patients who survived several years without BCR.

Methods

Between January 2009 and December 2018, 877 patients with complete clinicopathologic and follow-up data were included. Using the Kaplan–Meier estimation, the probabilities of C-BCRFS after RP were estimated in patients who did not experience BCR at 0–4 years. C-BCRFS was analyzed according to the National Comprehensive Cancer Network risk classification and compared using the log-rank test. Prognostic factors at each year without BCR were evaluated using multivariable Cox regression analysis.

Results

The median follow-up duration and patient age were 48 months and 67 years, respectively. As the BCR-free interval increased (baseline, 1, 2, 3, and 4 years after RP), the 5-year C-BCRFS rates improved marginally (74.8%, 83.2%, 89.1%, 93.6%, and 98.5%, respectively). However, the 5-year C-BCRFS rates in the high/very high-risk group rose from 54.0% at baseline to 67.6%, 80.3%, 88.6, and 97.8% after 1–4 years free of BCR, respectively. In patients with a BCR-free duration more than 1 year, only seminal vesicle invasion and pathological Gleason score were significant predictive factors of BCR thereafter.

Conclusion

In the high/very high-risk group, the C-BCRFS markedly improved as the interval without BCR increased. In patients who were BCR-free for several years, seminal vesicle invasion and pathological Gleason score were prognostic factors of continued BCRFS. This is useful not only for patient counseling but also to optimize postoperative follow-up strategies.