Re-evaluating the biological significance of seminal vesicle invasion (SVI) in locally advanced prostate cancer

The Sensitivity and Specificity of Multiparametric Magnetic Resonance Imaging and Prostate-Specific Membrane Antigen Positron Emission Tomography/Computed Tomography for Predicting Seminal Vesicle Invasion in Clinically Significant Prostate Cancer: A Multicenter Retrospective Study

Background/Objectives: The presence of seminal vesicle invasion (SVI) in prostate cancer (PCa) is associated with poorer postoperative outcomes. This study evaluates the predictive value of magnetic resonance imaging (MRI) and prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) for SVI in PCa. Methods: This cohort study included consecutive robotic prostatectomy patients for PCa at three Australian tertiary referral centres between April 2016 and September 2022. MRI and PSMA PET/CT results, clinicopathological variables, including age, BMI, prostate-specific antigen (PSA), PSA density, DRE, Biopsy Gleason score, Positive biopsy cores, PIRADS v2.1 score, MRI volume and MRI lesion size were extracted. The sensitivity, specificity, and accuracy of MRI and PSMA PET/CT for predicting SVI were compared with the histopathological results by receiver operating characteristic (ROC) analysis. Subgroup univariate and multivariate analysis was performed. Results: Of the 528 patients identified, 86 had SVI on final pathology. MRI had a low sensitivity of 0.162 (95% CI: 0.088-0.261) and a high specificity of 0.963 (95% CI: 0.940-0.979). The PSMA PET/CT had a low sensitivity of 0.439 (95% CI: 0.294-0591) and a high specificity of 0.933 (95% CI: 0.849-0.969). When MRI and PSMA PET/CT were used in combination, the sensitivity and specificity improved to 0.514 (95%CI: 0.356-0.670) and 0.880 (95% CI: 0.813-0.931). The multivariate regression showed a higher biopsy Gleason score (p = 0.033), higher PSA (p < 0.001), older age (p = 0.001), and right base lesions (p = 0.003) to be predictors of SVI. Conclusions: MRI and PSMA PET/CT independently underpredicted SVI. The sensitivity and AUC improved when they were used in combination. Multiple clinicopathological factors were associated with SVI on multivariate regression and predictive models incorporating this information may improve oncological outcomes.

Bilateral Seminal Vesicle Invasion Is Not Associated with Worse Outcomes in Locally Advanced Prostate Carcinoma

Background and Objectives: Patients with seminal vesicle invasion (SVI) are a highly heterogeneous group. Prognosis can be affected by many clinical and pathological characteristics. Our aim was to study whether bilateral SVI (bi-SVI) is associated with worse oncological outcomes. Materials and Methods: This is an observational retrospective study that included 146 pT3b patients treated with radical prostatectomy (RP). We compared the results between unilateral SVI (uni-SVI) and bi-SVI. The log-rank test and Kaplan–Meier curves were used to compare biochemical recurrence-free survival (BCR), metastasis-free survival (MFS), and additional treatment-free survival. Cox proportional hazard models were used to identify predictors of BCR-free survival, MFS, and additional treatment-free survival. Results: 34.93% of patients had bi-SVI. The median follow-up was 46.84 months. No significant differences were seen between the uni-SVI and bi-SVI groups. BCR-free survival at 5 years was 33.31% and 25.65% (p = 0.44) for uni-SVI and bi-SVI. MFS at 5 years was 86.03% vs. 75.63% (p = 0.1), and additional treatment-free survival was 36.85% vs. 21.93% (p = 0.09), respectively. In the multivariate analysis, PSA was related to the development of BCR [HR 1.34 (95%CI: 1.01–1.77); p = 0.03] and metastasis [HR 1.83 (95%CI: 1.13–2.98); p = 0.02]. BCR was also influenced by lymph node infiltration [HR 2.74 (95%CI: 1.41–5.32); p = 0.003]. Additional treatment was performed more frequently in patients with positive margins [HR: 3.50 (95%CI: 1.65–7.44); p = 0.001]. Conclusions: SVI invasion is an adverse pathology feature, with a widely variable prognosis. In our study, bilateral seminal vesicle invasion did not predict worse outcomes in pT3b patients despite being associated with more undifferentiated tumors.

Novel nomogram for the prediction of seminal vesicle invasion including multiparametric magnetic resonance imaging

OBJECTIVES

To create a model that predicts side-specific seminal vesicle invasion using clinical, biopsy and multiparametric magnetic resonance imaging data.

METHODS

We analyzed data from 544 patients who underwent robot-assisted radical prostatectomy at a single institution. To develop a side-specific predictive model, we ultimately considered four variables: prostate-specific antigen, highest ipsilateral biopsy Gleason grade, highest ipsilateral percentage core involvement and seminal vesicle invasion on multiparametric magnetic resonance imaging. A binary multivariable logistic regression model was fitted to predict seminal vesicle invasion. A nomogram was then built based on the coefficients of the resulting logit function. The leave-one-out cross validation method was used for internal validation, and the decision curve analysis for the evaluation of the net clinical benefit.

RESULTS

We relied on 804 side-specific cases after excluding negative biopsy observations (n = 284). Seminal vesicle invasion was reported on multiparametric magnetic resonance imaging in 41 (5%) cases, and on final pathology in 64 (8%) cases. All variables in the model emerged as predictors of seminal vesicle invasion (all P ≤ 0.001) and were subsequently considered to build a nomogram. The area under the curve of multiparametric magnetic resonance imaging alone in predicting seminal vesicle invasion was 59.1%; whereas one of the clinical variables only was 85.1%. The area under the curve of the nomogram resulting from their combination was 86.5%. After internal validation, this resulted in 84.7%. The model achieved good calibration and the decision curve analysis showed its clinical benefit, especially when compared with relying only on multiparametric magnetic resonance imaging prediction of seminal vesicle invasion.

CONCLUSIONS

A nomogram based on clinical and multiparametric magnetic resonance imaging data can predict seminal vesicle invasion and serve as a tool to urologists for surgical planning.

Prognostic significance and biopsy characteristics of prostate cancer with seminal vesicle invasion on radical prostatectomy: a nationwide population-based study

The objective of this study was to evaluate the prognostic significance of seminal vesicle invasion (SVI, pT3b) compared with extraprostatic extension (EPE) alone (pT3a) after radical prostatectomy, and to correlate pre-operative biopsy pathology with SVI and EPE. The National Prostate Cancer Register includes all prostate cancers diagnosed in Sweden. We analysed 4063 cases with stage category pT3a and 1371 cases with pT3b at radical prostatectomy between 2000 and 2012. Associations between pT3a and pT3b and progression were evaluated and adjusted for year, age, biopsy grade and s-PSA. Needle biopsy findings in these stages were compared. Patients with pT3b (n=1371) had a higher risk of death from prostate cancer (HR 2.3, 95% CI 1.5-3.3, p<0.001) and death from any cause (HR 1.5, 95% CI 1.2-1.8, p<0.001) than those with pT3a (n=4063). They were also more likely to be treated with post-operative radiotherapy (HR 1.5, 95% CI 1.4-1.7, p<0.001) or androgen deprivation therapy (HR 3.0, 95% CI 2.5-3.7, p<0.001), indicating clinical progression. Yet, disease-specific survival of patients with stage pT3b was 94% after 6 years. Median cancer extent in pre-operative biopsies of pT3a and pT3b was 14 and 24 mm (p<0.001), number of positive cores was four and five, (p<0.001) and biopsy Gleason score was 8-10 in 11.6% and 27.3%, respectively (p<0.001). SVI of prostate cancer is associated with worse outcome after radical prostatectomy than EPE alone. However, few patients with SVI die within 6 years from surgery, suggesting that radical prostatectomy may be curative in locally advanced cancers.

Long-term utility of adjuvant hormonal and radiation therapy for patients with seminal vesicle invasion at radical prostatectomy

OBJECTIVE

To investigate the long-term utility of adjuvant therapy after radical prostatectomy (RP) for prostate cancer with seminal vesicle invasion (SVI; pT3b), as the published data are conflicting.

PATIENTS AND METHODS

Patients with SVI during RP and pelvic lymph node dissection at two major referral centres from 1986 to 2014 were included. Kaplan-Meier analyses and multivariable Cox regressions were used to determine if adjuvant radiotherapy (aRT) and adjuvant hormonal therapy (aHT) were predictors of biochemical recurrence (BCR), cancer-specific mortality (CSM) and overall mortality (OM). Subset analyses were performed for pN0 patients and pN+ patients.

RESULTS

Overall, 3 279 patients with prostate cancer and SVI were included with a median follow-up of 148 months. Considering the whole SVI population, 1 387 (42%) received no adjuvant therapy, 1 179 (36%) received aHT, 461 (14.1%) received aRT, while 252 (7.7%) received both aHT and aRT. The 10-year BCR, CSM, and OM rates were 64%, 14%, and 27%, respectively. In the overall population, aRT and aHT were predictors of BCR, CSM and OM (all P < 0.04). When only pT3bN0 patients were considered, aHT was a significant multivariate predictor of BCR [hazard ratio (HR) 0.50, P < 0.001), CSM (HR 0.62, P = 0.01) and OM (HR 0.75, P = 0.004). Conversely, aRT was not associated with survival outcomes (all P > 0.05). When only the subgroup pT3bN+ was considered, the use of aRT was related to an improvement in CSM (HR 0.65, P = 0.03) and OM (HR 0.78, P = 0.03).

CONCLUSIONS

aHT + aRT seems to be effective in pT3b patients. However, when stratified according to the presence of nodal metastases, aHT remains effective only in the node-negative subgroup, while aRT remains effective only in the node-positive subgroup. Further data including prospective trials are warranted to study the utility of adjuvant therapies in this setting.

Vas deferens invasion: A neglected issue in the sampling of radical prostatectomy materials

A radical prostatectomy affects the prostate, bilateral seminal vesicles (SV), and the distal parts of the bilateral vasa deferentia (VD). SV invasion (SVI) is associated with an increased risk of lymph node metastasis and recurrence. However, the significance of VD invasion (VDI), either with or without the involvement of their surgical margins, has not been fully appreciated. We think VDI might have an independent prognostic significance, as does SVI, and should be incorporated into the pathology guidelines and the staging systems of prostatic adenocarcinoma. Our case illustrates this.

miR-888 is an expressed prostatic secretions-derived microRNA that promotes prostate cell growth and migration

MicroRNAs (MiRNAs) are a growing class of small non-coding RNAs that exhibit widespread dysregulation in prostate cancer. We profiled miRNA expression in syngeneic human prostate cancer cell lines that differed in their metastatic potential in order to determine their role in aggressive prostate cancer. miR-888 was the most differentially expressed miRNA observed in human metastatic PC3-ML cells relative to non-invasive PC3-N cells, and its levels were higher in primary prostate tumors from cancer patients, particularly those with seminal vesicle invasion. We also examined a novel miRNA-based biomarker source called expressed prostatic secretions in urine (EPS urine) for miR-888 expression and found that its levels were preferentially elevated in prostate cancer patients with high-grade disease. These expression studies indicated a correlation for miR-888 in disease progression. We next tested how miR-888 regulated cancer-related pathways in vitro using human prostate cancer cell lines. Overexpression of miR-888 increased proliferation and migration, and conversely inhibition of miR-888 activity blocked these processes. miR-888 also increased colony formation in PC3-N and LNCaP cells, supporting an oncogenic role for this miRNA in the prostate. Our data indicates that miR-888 functions to promote prostate cancer progression and can suppress protein levels of the tumor suppressor genes RBL1 and SMAD4. This miRNA holds promise as a diagnostic tool using an innovative prostatic fluid source as well as a therapeutic target for aggressive prostate cancer.