Which Patients with Prostate Cancer and Lymph Node Uptake at Preoperative Prostate-specific Membrane Antigen Positron Emission Tomography/Computerized Tomography Scan Are at a Higher Risk of Prostate-specific Antigen Persistence After Radical Prostatectomy? Identifying Indicators of Systemic Disease by Integrating Clinical, Magnetic Resonance Imaging, and Functional Imaging Parameters

BACKGROUND

The role of local therapies including radical prostatectomy (RP) in prostate cancer (PCa) patients with clinical lymphadenopathies on prostate-specific membrane antigen (PSMA) positron emission tomography/computerized tomography (PET/CT) has scarcely been explored. Limited data are available to identify men who would benefit from RP; on the contrary, those more likely to benefit already have systemic disease.

OBJECTIVE

We aimed to assess the predictors of prostate-specific antigen (PSA) persistence in surgically managed PCa patients with lymphadenopathies on a PSMA PET/CT scan by integrating clinical, magnetic resonance imaging (MRI), and PSMA PET/CT parameters.

DESIGN, SETTING, AND PARTICIPANTS

We identified 519 patients treated with RP and extended lymph node dissection, and who received preoperative PSMA PET between 2017 and 2022 in nine referral centers. Among them, we selected 88 patients with nodal uptake at preoperative PSMA PET (miTxN1M0).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The outcome was PSA persistence, defined as a PSA value of ≥0.1 ng/ml at the first measurement after surgery. Multivariable logistic regression models tested the predictors of PSA persistence. Covariates consisted of biopsy International Society of Urological Pathology (ISUP) grade group, clinical stage at MRI, and number of positive spots at a PET/CT scan. A regression tree analysis stratified patients into risk groups based on preoperative characteristics.

RESULTS AND LIMITATIONS

Overall, lymph node invasion (LNI) was detected in 63 patients (72%) and 32 (36%) experienced PSA persistence after RP. At multivariable analyses, having more than two lymph nodal positive findings at PSMA PET, seminal vesicle invasion (SVI) at MRI, and ISUP grade group >3 at biopsy were independent predictors of PSA persistence (all p < 0.05). At the regression tree analysis, patients were stratified in four risk groups according to biopsy ISUP grade, number of positive findings at PET/CT, and clinical stage at MRI. The model depicted good discrimination at internal validation (area under the curve 78%).

CONCLUSIONS

One out of three miN1M0 patients showed PSA persistence after surgery. Patients with ISUP grade 2-3, as well as patients with organ-confined disease at MRI and a single or two positive nodal findings at PET are those in whom RP may achieve the best oncological outcomes in the context of a multimodal approach. Conversely, patients with a high ISUP grade and extracapsular extension or SVI or more than two spots at PSMA PET should be considered as potentially affected by systemic disease upfront.

PATIENT SUMMARY

Our novel and straightforward risk classification integrates currently available preoperative risk tools and should, therefore, assist physician in preoperative counseling of men candidates for radical treatment for prostate cancer with positive lymph node uptake at prostate-specific membrane antigen positron emission tomography.

Definition and Impact on Oncologic Outcomes of Persistently Elevated Prostate-specific Antigen After Salvage Lymph Node Dissection for Node-only Recurrent Prostate Cancer After Radical Prostatectomy: Clinical Implications for Multimodal Therapy

BACKGROUND

The optimal definition and prognostic significance of persistently elevated prostate-specific antigen (PSA) after salvage lymph node dissection (sLND) for node-only recurrent prostate cancer (PCa) remain unknown.

OBJECTIVE

To assess the definition and clinical implications of persistently elevated PSA after sLND for node-only recurrent PCa after radical prostatectomy.

DESIGN, SETTING, AND PARTICIPANTS

The study included 579 patients treated with sLND at 11 high-volume centers between 2000 and 2016.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We assessed the linear relationship between the first PSA after sLND and death from PCa. Different definitions of PSA persistence were included in a multivariable model predicting cancer-specific mortality (CSM) after surgery to identify the best cutoff value. We investigated the association between PSA persistence and oncologic outcomes using multivariable regression models. Moreover, the effect of early androgen deprivation therapy (ADT) after sLND was tested according to PSA persistence status and estimated risk of CSM.

RESULTS AND LIMITATIONS

We found an inverse relationship between the first PSA after sLND and the probability of cancer-specific survival. PSA persistence defined as first postoperative PSA ≥0.3 ng/ml provided the best discrimination accuracy (C index 0.757). According to this cutoff, 331 patients (57%) experienced PSA persistence. The median follow-up for survivors was 48 mo (interquartile range 27-74). After adjusting for confounders, men with persistently elevated PSA had higher risk of clinical recurrence (hazard ratio [HR] 1.61), overall mortality (HR 2.20), and CSM (HR 2.59; all p < 0.001) after sLND. Early ADT administration after sLND improved survival only for patients with PSA persistence after surgery (HR 0.49; p = 0.024). Similarly, when PSA persistence status was included in multivariable models accounting for pathologic features, early ADT use after sLND was beneficial only for patients with a predicted risk of CSM at 5 yr of >10%.

CONCLUSIONS

PSA persistence after sLND independently predicts adverse prognosis, with the best discrimination accuracy for CSM provided by a definition of PSA ≥ 0.3 ng/ml. We showed that when stratifying patients by final pathology results and PSA persistence status, early ADT use after sLND was beneficial only for patients with PSA persistence or with a calculated 5-yr risk of CSM of >10%, which could be useful as we await results from ongoing prospective trials.

PATIENT SUMMARY

We found that for patients with prostate cancer who had lymph nodes removed after their cancer recurred, persistently elevated prostate-specific antigen (PSA) levels predict poorer prognosis. We showed that a PSA level of ≥0.3 ng/ml provides the best accuracy in identifying patients with worse prognosis. This may help to improve risk stratification after lymph node removal and allow physicians to optimize treatment strategies after surgery.

Comparison of hypofractionation and standard fractionation for post-prostatectomy salvage radiotherapy in patients with persistent PSA: single institution experience

BACKGROUND

Hypofractionated post-prostatectomy radiotherapy is emerging practice, however with no randomized evidence so far to support it's use. Additionally, patients with persistent PSA after prostatectomy may have aggressive disease and respond less well on standard salvage treatment. Herein we report outcomes for conventionally fractionated (CFR) and hypofractionated radiotherapy (HFR) in patients with persistent postprostatectomy PSA who received salvage radiotherapy to prostate bed.

METHODS

Single institution retrospective chart review was performed after Institutional Review Board approval. Between May 2012 and December 2016, 147 patients received salvage postprostatectomy radiotherapy. PSA failure-free and metastasis-free survival were calculated using Kaplan-Meier method. Cox regression analysis was performed to test association of fractionation regimen and other clinical factors with treatment outcomes. Early and late toxicity was assessed using Common Terminology Criteria for Adverse Events (CTCAE) Version 4.0.

RESULTS

Sixty-nine patients who had persistent PSA (≥ 0.1 ng/mL) after prostatectomy were identified. Median follow-up was 67 months (95% CI 58-106 months, range, 8-106 months). Thirty-six patients (52.2%) received CFR, 66 Gy in 33 fractions, 2 Gy per fraction, and 33 patients (47.8%) received HFR, 52.5 Gy in 20 fractions, 2.63 Gy per fraction. Forty-seven (68%) patients received androgen deprivation therapy (ADT). 5-year PSA failure- and metastasis-free survival rate was 56.9% and 76.9%, respectively. Thirty patients (43%) experienced biochemical failure after salvage radiotherapy and 16 patients (23%) experienced metastatic relapse. Nine patients (13%) developed metastatic castration-resistant disease and died of advanced prostate cancer. Median PSA failure-free survival was 72 months (95% CI; 41-72 months), while median metastasis-free survival was not reached. Patients in HFR group were more likely to experience shorter PSA failure-free survival when compared to CFR group (HR 2.2; 95% CI 1.0-4.6, p = 0.04). On univariate analysis, factors significantly associated with PSA failure-free survival were radiotherapy schedule (CFR vs HFR, HR 2.2, 95% CI 1.0-4.6, p = 0.04), first postoperative PSA (HR 1.02, 95% CI 1.0-1.04, p = 0.03), and concomitant ADT (HR 3.3, 95% CI 1.2-8.6, p = 0.02). On multivariate analysis, factors significantly associated with PSA failure-free survival were radiotherapy schedule (HR 3.04, 95% CI 1.37-6.74, p = 0.006) and concomitant ADT (HR 4.41, 95% CI 1.6-12.12, p = 0.004). On univariate analysis, factors significantly associated with metastasis-free survival were the first postoperative PSA (HR 1.07, 95% CI 1.03-1.12, p = 0.002), seminal vesicle involvement (HR 3.48, 95% CI 1.26-9.6,p = 0.02), extracapsular extension (HR 7.02, 95% CI 1.96-25.07, p = 0.003), and surgical margin status (HR 2.86, 95% CI 1.03-7.97, p = 0.04). The first postoperative PSA (HR 1.04, 95% CI 1.00-1.08, p = 0.02) and extracapsular extension (HR 4.24, 95% CI 1.08-16.55, p = 0.04) remained significantly associated with metastasis-free survival on multivariate analysis. Three patients in CFR arm (8%) experienced late genitourinary grade 3 toxicity.

CONCLUSIONS

In our experience, commonly used hypofractionated radiotherapy regimen was associated with lower biochemical control compared to standard fractionation in patients with persistent PSA receiving salvage radiotherapy. Reason for this might be lower biological dose in HFR compared to CFR group. However, this observation is limited due to baseline imbalances in ADT use, ADT duration and Grade Group distribution between two radiotherapy cohorts. In patients with persistent PSA post-prostatectomy, the first postoperative PSA is an independent risk factor for treatment failure. Additional studies are needed to corroborate our observations.

Impact of Postoperative Radiotherapy in Men with Persistently Elevated Prostate-specific Antigen After Radical Prostatectomy for Prostate Cancer: A Long-term Survival Analysis

BACKGROUND

Prostate cancer (PCa) patients with prostate-specific antigen (PSA) persistence after radical prostatectomy (RP) are at increased risk of mortality, although the natural history of these men is heterogeneous and the optimal management has not been established.

OBJECTIVE

To develop a model to predict cancer-specific mortality (CSM) and to test the impact of radiotherapy (RT) on survival in this setting.

DESIGN, SETTING, AND PARTICIPANTS

We identified 496 patients treated with RP and lymph node dissection at two referral centers between 1994 and 2014 who had PSA persistence, defined as a PSA level between 0.1 and 2 ng/ml at 6-8 wk after RP.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSES

A multivariable model predicting CSM was developed. We assessed whether the impact of postoperative PSA levels on survival differed according to baseline CSM risk. The nonparametric curve fitting method was then used to explore the relationship between baseline CSM risk and 10-yr CSM rates according to postoperative RT.

RESULTS AND LIMITATIONS

Median follow-up for survivors was 110 mo. Overall, 49 patients experienced CSM. The 10-yr CSM-free survival was 88%. Pathologic grade group and pathologic stage were independent predictors of CSM (all p=0.01). The association between CSM-free survival and PSA at 6-8 wk differed by the baseline CSM risk, whereby the effect of increasing PSA was evident only in patients with a CSM risk of ≥10%. Postoperative RT was beneficial when the predicted risk of CSM was ≥30% (p=0.001 by an interaction test). Our study is limited by its retrospective design.

CONCLUSIONS

Increasing PSA levels should be considered as predictors of mortality exclusively in men with worse pathologic characteristics. Postoperative RT in this setting was associated with a survival benefit in patients with a CSM risk of ≥30%. Conversely, individuals with a CSM risk of <30% should be initially managed expectantly.

PATIENT SUMMARY

Not all patients with prostate-specific antigen persistence have a poor prognosis. Pathologic characteristics should be used to estimate the risk of cancer-specific mortality in these individuals and to identify patients who could benefit from postoperative radiotherapy.