Prognostic factors in lymph node-positive prostate cancer

The prognostic value of lymph node staging with prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) and extended pelvic lymph node dissection in node-positive patients with prostate cancer

OBJECTIVES

To investigate whether patients with suspected pelvic lymph node metastases (molecular imaging [mi] N1) on staging prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) had a different oncological outcome compared to those in whom the PSMA PET/CT did not reveal any pelvic lymph node metastases (miN0).

PATIENTS AND METHODS

All patients with pelvic lymph node metastatic (pN1) disease after robot-assisted radical prostatectomy (RARP) and extended pelvic lymph node dissection (ePLND) between January 2017 and December 2020 were included. To assess predictors of biochemical progression of disease after RARP, a multivariable Cox regression analysis was performed, including number of tumour-positive lymph nodes, diameter of the largest nodal metastasis, and extranodal extension.

RESULTS

In total, 145 patients were diagnosed with pN1 disease after ePLND. The median biochemical progression-free survival in patients with miN0 on PSMA PET/CT was 13.7 months, compared to 7.9 months in patients with miN1 disease (P = 0.006). On multivariable Cox regression analysis, both number of tumour-positive lymph nodes (>2 vs 1-2: hazard ratio [HR] 1.97; P = 0.005) and diameter of the largest nodal metastasis (HR 1.12; P < 0.001) were significant independent predictors of biochemical progression of disease.

CONCLUSION

Patients in whom pelvic lymph node metastases were suspected on preoperative PSMA imaging (miN1), patients diagnosed with >2 tumour-positive lymph nodes, and patients with a larger diameter of the largest nodal metastasis had a significantly increased risk of biochemical disease progression after surgery.

Current Status and Future Perspective on the Management of Lymph Node-Positive Prostate Cancer after Radical Prostatectomy

Pathological lymph node involvement (pN1) after a pelvic lymph node dissection represents one of the most unfavorable prognostic factors for disease recurrence and cancer-specific mortality in prostate cancer. However, optimal management for pN1 patients remains unclear. Thus, the guideline from the European Association of Urology recommends discussing three following management options with pN1 patients after an extended pelvic lymph node dissection, based on nodal involvement characteristics: (i) offer adjuvant androgen-deprivation therapy, (ii) offer adjuvant androgen-deprivation therapy with additional radiotherapy and (iii) offer observation (expectant management) to a patient with ≤2 nodes and a prostate-specific antigen <0.1 ng/mL. Treatment intensification may reduce risks of recurrence and cancer-specific mortality, but it may increase adverse events and impair quality of life. Few randomized control trials for pN1 are under investigation. In addition, there are limited reports on the quality of life and patient-reported outcomes in patients with pN1. Therefore, more research is needed to establish an optimal therapeutic strategy for patients with pN1. This review summarizes current evidence on the treatments available for men with pN1, summarizes randomized control trials that included pN1 prostate cancer, and discusses future perspectives.

The Impact of the Ongoing COVID-19 Epidemic on the Increasing Risk of Adverse Pathology in Prostate Cancer Patients Undergoing Radical Prostatectomy

We aimed to assess whether the ongoing course of the COVID-19 epidemic has been associated with an increased risk of adverse pathology (AP) findings in prostate cancer (PC) patients treated with radical prostatectomy (RP). We performed a retrospective data analysis which included 408 consecutive, non-metastatic, previously untreated PC patients who underwent RP in our institution between March 2020 and September 2021. Patients were divided into two equally numbered groups in regard to the median surgery date (Early Epidemic [EE] and Late Epidemic [LE]) and compared. Adverse pathology was defined as either grade group (GG) ≥ 4, pT ≥ 3a or pN+ at RP. Patients in the LE group demonstrated significantly higher rates of AP than in the EE group (61 vs. 43% overall and 50 vs. 27% in preoperative non-high-risk subgroup, both p < 0.001), mainly due to higher rates of upgrading. On multivariable analysis, consecutive epidemic week (odds ratio: 1.02, 95% confidence interval: 1.00−1.03, p = 0.009) as well as biopsy GG ≥ 2 and a larger prostate volume (mL) were associated with AP in non-high-risk patients. The study serves as a warning call for increased awareness of risk underassessment in contemporarily treated PC patients.

Management of Patients with Node-positive Prostate Cancer at Radical Prostatectomy and Pelvic Lymph Node Dissection: A Systematic Review

CONTEXT

Optimal management of prostate cancer (PCa) patients with lymph node invasion at radical prostatectomy and pelvic lymph node dissection still remains unclear.

OBJECTIVE

To assess the effectiveness of postoperative treatment strategies for pathologically node-positive PCa patients. The secondary aim was to identify the most relevant prognostic factors to guide the management of pN1 patients.

EVIDENCE ACQUISITION

A systematic review was performed in January 2020 using Medline, Embase, and other databases. A total of 5063 articles were screened, and 26 studies including 12 537 men were selected for data synthesis and included in the current review according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) recommendations.

EVIDENCE SYNTHESIS

Ten-year biochemical recurrence (BCR)-free, clinical recurrence-free, cancer-specific (CSS), and overall (OS) survival rates ranged from 28% to 56%, 70% to 92%, 72% to 98%, and 60% to 87.6%, respectively. A total of seven, five, and six studies assessed the oncological outcomes of observation, adjuvant radiotherapy (aRT), or adjuvant androgen deprivation therapy (ADT), respectively. Initial observation followed by salvage therapies at the time of recurrence represents a safe option in selected patients with a low disease burden. The use of aRT with or without ADT might improve survival in men with locally advanced disease and a higher number of positive nodes. Risk stratification according to pathological Gleason score, number of positive nodes, pathological stage, and surgical margins status is the key to risk stratification and selection of the optimal postoperative therapy. Limitations of this systematic review are the retrospective design of the studies included and the lack of data on adverse events.

CONCLUSIONS

While the majority of men with pN1 disease would experience BCR after surgery, long-term disease-free survival has been reported in selected patients. Management options to improve oncological outcomes include observation versus adjuvant therapies such as aRT and/or ADT. Disease characteristics should be used to select the optimal postoperative management for pN1 PCa patients.

PATIENT SUMMARY

Finding node-positive prostate cancer after a radical prostatectomy often leads to high postoperative prostate-specific antigen levels and is overall a poor prognostic factor. However, this does not necessarily translate into poor survival for all men. Management can be tailored to the severity of disease and options include observation, androgen deprivation therapy, and/or radiotherapy.

Sentinel node evaluation in prostate cancer

Sentinel lymph node (SLN) based pelvic lymph node dissection (PLND) in prostate cancer (PCa) is appealing over the time, cost and morbidity classically attributed to conventional PLND during radical prostatectomy. The initial report of feasibility of the SLN concept in prostate cancer was nearly 20 years ago. However, PLND based on the SLN concept, either SLN biopsy of a single node or targeted SLN dissection of multiple nodes, is still considered investigational in PCa. To better appreciate the challenges, and potential solutions, associated with SLN-based PLND in PCa, this review will discuss the rationale behind PLND in PCa and evaluate current SLN efforts in the most commonly diagnosed malignancy in men in the US.

Extranodal extension of lymph node metastasis influences recurrence in prostate cancer: a systematic review and meta-analysis

The extranodal extension (ENE) of nodal metastasis involves the extension of neoplastic cells through the lymph node capsule into the perinodal adipose tissue. This morphological feature has recently been indicated as an important prognostic factor in various cancer types, but its role in prostate cancer is still unclear. We aimed to clarify it, performing the first meta-analysis on this issue, comparing prognostic parameters in surgically treated, node-positive prostate cancer patients with (ENE+) vs. without (ENE-) ENE. Data were summarized using risk ratios (RRs) for number of deaths/recurrences and hazard ratios (HRs), with 95% confidence intervals (CI), for the time-dependent risk related to ENE positivity. Six studies followed-up 1,113 patients with N1 prostate cancer (658 ENE+ vs. 455 ENE-) for a median of 83 months. The presence of ENE was associated with a significantly higher risk of biochemical recurrence (RR = 1.15; 95%CI: 1.03-1.28; I2 = 0%; HR = 1.40, 95%CI: 1.12-1.74; I2 = 0%) and "global" (biochemical recurrence and distant metastasis) recurrence (RR = 1.15; 95%CI: 1.04-1.28; I2 = 0%; HR = 1.41, 95%CI: 1.14-1.74; I2 = 0%). ENE emerged as a potential prognostic moderator, earmarking a subgroup of patients at higher risk of recurrence. It may be considered for the prognostic stratification of metastatic patients. New possible therapeutic approaches may explore more in depth this prognostic parameter.

The prognostic value of lymphovascular invasion in radical prostatectomy: a systematic review and meta-analysis

To systematically evaluate the prognostic value of lymphovascular invasion (LVI) in radical prostatectomy (RP) by a meta-analysis based on the published literature. To identify relevant studies, PubMed, Cochrane Library, and Web of Science database were searched from 1966 to May 2014. Finally, 25 studies (9503 patients) were included. LVI was found in 12.2% (1156/9503) of the RP specimens. LVI was found to be correlated with higher pathological tumor stages (greater than pT3 stage) (risk ratio [RR] 1.90, 95% confidence interval [CI] 1.73–2.08, P < 0.00001), higher Gleason scores (greater than GS = 7) (RR 1.30, 95% CI 1.23–1.38, P < 0.00001), positive pathological node (pN) status (RR 5.67, 95% CI 3.14–10.24, P < 0.00001), extracapsular extension (RR 1.72, 95% CI 1.46–2.02, P < 0.00001), and seminal vesicle involvement (RR 3.36, 95% CI 2.41–4.70, P < 0.00001). The pooled hazard ratio (HR) was statistically significant for Biochemical Recurrence-Free (BCR-free) probability (HR 2.05, 95% CI 1.64–2.56; Z = 6.30, P < 0.00001). Sensitivity analysis showed that the pooled HR and 95% CI were not significantly altered by the omission of any single study. Begg's Funnel plots showed no significant publication bias (P = 0.112). In conclusion, LVI exhibited a detrimental effect on the BCR-Free probability and clinicopathological features in RP specimens, and may prove to be an independent prognostic factor of BCR.

Lymph node staging in prostate cancer: perspective for the pathologist

Pelvic lymph node dissection (PLND) currently represents the gold standard method for nodal staging in the setting of localised prostate cancer and may also have a therapeutic benefit in certain patients. The histopathological evaluation of PLND specimens plays a critical role in accurate lymph node staging, however there is currently a lack of consensus regarding the optimum approach and no quality parameters are in place. In addition, there are no guidelines as to the handling of less commonly encountered nodal specimens such as those identified within the anterior fat pad. This summary provides an overview of pertinent issues regarding lymph node staging in prostate cancer, with a focus on the histopathological evaluation of resected nodal specimens. We hope that this review will further the discussion on how to achieve a more standardised approach to the processing and reporting of PLND specimens in the setting of prostate cancer.

Integrating chemohormonal therapy and surgery in known or suspected lymph node metastatic prostate cancer

BACKGROUND

Prostate cancer persisting in the primary site after systemic therapy may contribute to emergence of resistance and progression. We previously demonstrated molecular characteristics of lethal cancer in the prostatectomy specimens of patients presenting with lymph node metastasis after chemohormonal treatment. Here we report the post-treatment outcomes of these patients and assess whether a link exists between surgery and treatment-free/cancer-free survival.

METHODS

Patients with either clinically detected lymph node metastasis or primaries at high risk for nodal dissemination were treated with androgen ablation and docetaxel. Those responding with PSA concentration <1 ng ml(-1) were recommended surgery 1 year from enrollment. ADT was withheld postoperatively. The rate of survival without biochemical progression 1 year after surgery was measured to screen for efficacy.

RESULTS

Forty patients were enrolled and 39 were evaluable. Three patients (7.7%) declined surgery. Of the remaining 36, 4 patients experienced disease progression during treatment and 4 more did not reach PSA <1. Twenty-six patients (67%) completed surgery, and 13 (33%) were also progression-free 1 year postoperatively (8 with undetectable PSA). With a median follow-up of 61 months, time to treatment failure was 27 months in the patients undergoing surgery. The most frequent patterns of first disease recurrence were biochemical (10 patients) and systemic (5).

CONCLUSIONS

Half of the patients undergoing surgery were off treatment and progression-free 1 year following completion of all therapy. These results suggest that integration of surgery is feasible and may be superior to systemic therapy alone for selected prostate cancer patients presenting with nodal metastasis.

Salvage therapy of small volume prostate cancer nodal failures: a review of the literature

New imaging modalities may be useful to identify prostate cancer patients with small volume, limited nodal relapse ("oligo-recurrent") potentially amenable to local treatments (radiotherapy, surgery) with the aim of long-term control of the disease, even in a condition traditionally considered prognostically unfavorable. This report reviews the new diagnostic tools and the main published data about the role of surgery and radiation therapy in this particular subgroup of patients.

Gleason score 7 adenocarcinoma of the prostate with lymph node metastases: analysis of 184 radical prostatectomy specimens

CONTEXT

Prostate cancer (PC) with lymph node metastases (LN(+)) is relatively rare, whereas it is relatively common in disease with a Gleason score (GS) 8 to 10 and virtually never seen in PC with GS 6 or less. It is most variable in GS 7 PC.

OBJECTIVE

To determine clinicopathologic features associated with GS 7 PC with LN(+) compared with a control group without lymph node metastases (LN(-)).

DESIGN

We analyzed 184 GS 7 radical prostatectomies with LN(+) and the same number of LN(-) Gleason-matched controls. The LN(+) cases were GS 3 + 4 = 7 (n = 64; 34.8%), GS 4 + 3 = 7 (n = 66; 35.9%), GS 3 + 4 = 7 with tertiary 5 (n = 10; 5.4%), and GS 4 + 3 = 7 with tertiary 5 (n = 44; 23.9%).

RESULTS

The LN(+) cases demonstrated higher average values in preoperative prostate-specific antigen (12.2 versus 8.1 ng/mL), percentage of positive biopsy cores (59.1% versus 42.9%), prostate weight (54.4 versus 49.4 g), number of LNs submitted (12.7 versus 9.4), incidence of nonfocal extraprostatic extension (82.6% versus 63.6%), tumor volume (28.9% versus 14.8%), frequency of lymphovascular invasion (78.3% versus 38.6%), intraductal spread of carcinoma (42.4% versus 20.7%), incidence of satellite tumor foci (16.4% versus 4.3%), incidence of pT3b disease (49.5% versus 14.7%), and lymphovascular invasion in the seminal vesicles (52% versus 30%). There were differences in GS 4 patterns and cytology between LN(+) and LN(-) cases, with the former having higher volumes of cribriform and poorly formed patterns, larger nuclei and nucleoli, and more-frequent macronucleoli. All P ≤ .05.

CONCLUSION

Gleason score 7 PC with LN(+) has features highlighting a more-aggressive phenotype. These features can be assessed as prognostic markers in GS 7 disease on biopsy (eg, GS 4 pattern, intraductal spread, cytology) or at radical prostatectomies (all variables), even in men without LN dissection or LN(-) disease.

Findings in 12-core transrectal ultrasound-guided prostate needle biopsy that predict more advanced cancer at prostatectomy: analysis of 388 biopsy-prostatectomy pairs

We analyzed 5 features on 12-core transrectal ultrasound-guided prostate needle biopsy (TRUS) to predict the extent of cancer at radical prostatectomy (RP). In 388 TRUS-RP pairs, number of positive cores (NPC), percentage of each core involved (%PC), perineural invasion (PNI), Gleason score (GS), distribution of positive cores (DPC), and preoperative prostate-specific antigen (PSA) were correlated with extraprostatic extension (EPE), seminal vesicle invasion (SVI), positive surgical margin (R1), positive lymph nodes (N1), and tumor volume. All features predicted EPE and SVI. NPC, GS, %PC, and PNI strongly predicted R1 status. RP tumor volume was directly proportional to the NPC and %PC. PSA alone and with selected biopsy findings correlated with tumor volume, stage, SVI, and N1 (P < .0001). Contiguous DPC was a significant risk for EPE and SVI (P < .0001) compared with isolated positive cores. Findings at 12-core TRUS along with preoperative PSA reliably predict advanced local disease and have practical value as guides to effective planning for surgical resections.

Lymph node-positive prostate cancer: current issues, emerging technology and impact on clinical outcome

Lymph node metastasis in patients with prostate cancer indicates a poorer prognosis compared with patients without lymph node metastasis; however, some patients with node-positive disease have long-term survival. Many studies have attempted to discern what characteristics of lymph node metastasis are prognostically significant. These characteristics include nodal tumor volume, number of positive lymph nodes, lymph node density, extranodal extension, lymphovascular invasion and tumor dedifferentiation. Favorable characteristics of regional lymph node involvement included a smaller tumor size and smaller tumor volume. However, the current staging system for prostate cancer does not provide different subclassifications for patients with node-positive prostate cancer. In recent years numerous advanced technologies for the detection of lymph node metastasis have been developed, including molecular imaging techniques and the CellSearch Circulating Tumor Cell System. With the increased detection of patients with prostate cancer, emergence of new technology to identify lymph node metastasis and the number of radical prostatectomies being performed on the rise, subclassifying patients with lymph node-positive disease is imperative. Subclassification would provide a better picture of patient prognosis and allow for a better understanding of targeted therapies to treat patients with lymph node metastasis.

ERG rearrangement metastasis patterns in locally advanced prostate cancer

OBJECTIVES

To interrogate multifocal prostate cancer (PCa) to determine its predilection for metastasis, using ERG rearrangement as marker of clonality. A hallmark of PCa is that distinct tumor foci may arise independently, which has important biological and clinical implications. Recent studies characterizing ERG-rearranged PCa possessing intrafocal homogeneity but interfocal heterogeneity support this hypothesis.

METHODS

We studied 26 patients who underwent prostatectomy and lymphadenectomy with at least 2 distinct PCa foci and 1 lymph node (LN) metastasis. Each focus was assessed for size, Gleason score, ERG rearrangement, and TMPRSS2-ERG transcript.

RESULTS

Fifteen of 26 cases exhibited interfocal homogeneity with regard to ERG rearrangement (ie, presence vs absence of ERG rearrangement). ERG rearrangement was present in all foci for 6 and absent in all foci for 9 cases. Two cases revealed interfocal heterogeneity with regard to rearrangement mechanism (ie, rearrangement through insertion or deletion). Eight of 26 cases revealed interfocal heterogeneity with regard to rearrangement status. In all cases with at least 1 ERG rearranged focus, we found the corresponding LN metastasis harboring an ERG rearrangement. Interestingly, in a subset of cases the rearrangement status in the LN did not correspond to size or Gleason score. All but 2 ERG rearranged foci had detectable TMPRSS2-ERG transcript levels.

CONCLUSIONS

When multifocal PCa demonstrates both ERG-positive and ERG-negative foci, the positive foci have a greater predilection for metastasis. Larger studies are needed to confirm the potential additional risk an ERG rearranged focus confers on the likelihood of disease progression.

RHAMM (CD168) is overexpressed at the protein level and may constitute an immunogenic antigen in advanced prostate cancer disease

Localized prostate cancer (CaP) can be cured using several strategies. However, the need to identify active substances in advanced tumor stages is tremendous, as the outcome in such cases is still disappointing. One approach is to deliver human tumor antigen-targeted therapy, which is recognized by T cells or antibodies. We used data mining of the Cancer Immunome Database (CID), which comprises potential immunologic targets identified by serological screening of expression libraries. Candidate antigens were screened by DNA microarrays. Genes were then validated at the protein level by tissue microarrays, representing various stages of CaP disease. Of 43 targets identified by CID, 10 showed an overexpression on the complementary DNA array in CaP metastases. The RHAMM (CD168) gene, earlier identified by our group as an immunogenic antigen in acute and chronic leukemia, also showed highly significant overexpression in CaP metastases compared with localized disease and benign prostatic hyperplasia. At the protein level, RHAMM was highest in metastatic tissue samples and significantly higher in neoplastic localized disease compared with benign tissue. High RHAMM expression was associated with clinical parameters known to be linked to better clinical outcome. Patients with high RHAMM expression in the primaries had a significantly lower risk of biochemical failure. The number of viable cells in cell cultures was reduced in blocking experiments using hormone-sensitive and hormone-insensitive metastatic CaP cell lines. Acknowledging the proven immunogenic effects of RHAMM in leukemia, this antigen is intriguing as a therapeutic target in far-advanced CaP.

Moderate dose escalation in three-dimensional conformal localized prostate cancer radiotherapy: single-institutional experience in 398 patients comparing 66 Gy versus 70 Gy versus 74 Gy

PURPOSE

To evaluate the clinical outcome in prostate cancer patients treated at one single institution by the implementation of moderate dose escalation.

PATIENTS AND METHODS

A total of 398 patients with histologically verified localized prostate cancer (T1-3 Nx0 Mx0) were treated by three-dimensional conformal radiotherapy with/without additional hormonal therapy. Risk group distribution was as follows: 106 low-risk (27%), 164 intermediate-risk (41%), and 128 high-risk (32%) patients. Total local dose was increased from 66 Gy (1994-1998) to 70 Gy (1998-2003) and 74 Gy (1998-2005). Biochemical no evidence of disease (bNED: ASTRO/Phoenix definition) and late gastrointestinal/urogenital side effects (EORTC/RTOG) were assessed.

RESULTS

Median follow-up was 64 months. The 5-year bNED rates according to 66 Gy, 70 Gy and 74 Gy were 37%, 64% and 63% (ASTRO), and 54%, 74% and 69% (Phoenix), respectively. In multivariate analysis, age and T-stage were significant in predicting bNED. The 5-year bNED rates (ASTRO) according to 66 Gy, 70 Gy and 74 Gy were 40%, 78% and 73% in the low-risk group, 41%, 55% and 85% in the intermediate-risk group, and 30%, 53% and 52% in the high-risk group. Intermediate-risk patients showed a significant improvement of bNED by increasing the dose up to 74 Gy. The 5-year actuarial rates of gastrointestinal/urogenital side effects grade > or = 2 were 18%/16% (66 Gy), 20%/24% (70 Gy), and 27%/28% (74 Gy).

CONCLUSION

A benefit of local doses at a level of > or = 70 Gy could be detected showing the highest increase of prostate-specific antigen control in the intermediate-risk group. The amount of patients reporting of severe late side effects is small.

Oncosome formation in prostate cancer: association with a region of frequent chromosomal deletion in metastatic disease

Oncosomes have recently been described as membrane-derived microvesicles secreted by cancer cells, which transfer oncogenic signals and protein complexes across cell boundaries. Here, we show the rapid formation and secretion of oncosomes from DU145 and LNCaP human prostate cancer cells. Oncosome formation was stimulated by epidermal growth factor receptor activation and also by overexpression of membrane-targeted Akt1. Microvesicles shed from prostate cancer cells contained numerous signal transduction proteins and were capable of activating rapid phospho-tyrosine and Akt pathway signaling, and stimulating proliferation and migration, in recipient tumor cells. They also induced a stromal reaction in recipient normal cells. Knockdown of the actin nucleating protein Diaphanous Related Formin 3 (DRF3/Dia2) by RNA interference enhanced rates of oncosome formation, indicating that these structures resemble, and may be identical to, nonapoptotic membrane blebs, a feature of the amoeboid form of cell motility. Analysis of primary and metastatic human prostate tumors using 100K single nucleotide polymorphism arrays revealed a significantly higher frequency of deletion of the locus encoding DRF3 (DIAPH3) in metastatic tumors (P = 0.001) in comparison with organ-confined tumors. Fluorescence in situ hybridization confirmed increased chromosomal loss of DIAPH3 in metastatic tumors in a different cohort of patients (P = 0.006). These data suggest that microvesicles shed from prostate cancer cells can alter the tumor microenvironment in a manner that may promote disease progression. They also show that DRF3 is a physiologically relevant protein that seems to regulate this process.

Treatment-dependent androgen receptor mutations in prostate cancer exploit multiple mechanisms to evade therapy

Mutations in the androgen receptor (AR) that enable activation by antiandrogens occur in hormone-refractory prostate cancer, suggesting that mutant ARs are selected by treatment. To validate this hypothesis, we compared AR variants in metastases obtained by rapid autopsy of patients treated with flutamide or bicalutamide, or by excision of lymph node metastases from hormone-naïve patients. AR mutations occurred at low levels in all specimens, reflecting genetic heterogeneity of prostate cancer. Base changes recurring in multiple samples or multiple times per sample were considered putative selected mutations. Of 26 recurring missense mutations, most in the NH(2)-terminal domain (NTD) occurred in multiple tumors, whereas those in the ligand binding domain (LBD) were case specific. Hormone-naïve tumors had few recurring mutations and none in the LBD. Several AR variants were assessed for mechanisms that might underlie treatment resistance. Selection was evident for the promiscuous receptor AR-V716M, which dominated three metastases from one flutamide-treated patient. For the inactive cytoplasmically restricted splice variant AR23, coexpression with AR enhanced ligand response, supporting a decoy function. A novel NTD mutation, W435L, in a motif involved in intramolecular interaction influenced promoter-selective, cell-dependent transactivation. AR-E255K, mutated in a domain that interacts with an E3 ubiquitin ligase, led to increased protein stability and nuclear localization in the absence of ligand. Thus, treatment with antiandrogens selects for gain-of-function AR mutations with altered stability, promoter preference, or ligand specificity. These processes reveal multiple targets for effective therapies regardless of AR mutation.

Distinct genomic aberrations associated with ERG rearranged prostate cancer

Emerging molecular and clinical data suggest that ETS fusion prostate cancer represents a distinct molecular subclass, driven most commonly by a hormonally regulated promoter and characterized by an aggressive natural history. The study of the genomic landscape of prostate cancer in the light of ETS fusion events is required to understand the foundation of this molecularly and clinically distinct subtype. We performed genome-wide profiling of 49 primary prostate cancers and identified 20 recurrent chromosomal copy number aberrations, mainly occurring as genomic losses. Co-occurring events included losses at 19q13.32 and 1p22.1. We discovered three genomic events associated with ERG rearranged prostate cancer, affecting 6q, 7q, and 16q. 6q loss in nonrearranged prostate cancer is accompanied by gene expression deregulation in an independent dataset and by protein deregulation of MYO6. To analyze copy number alterations within the ETS genes, we performed a comprehensive analysis of all 27 ETS genes and of the 3 Mbp genomic area between ERG and TMPRSS2 (21q) with an unprecedented resolution (30 bp). We demonstrate that high-resolution tiling arrays can be used to pin-point breakpoints leading to fusion events. This study provides further support to define a distinct molecular subtype of prostate cancer based on the presence of ETS gene rearrangements.

Survival in surgically treated, nodal positive prostate cancer patients is predicted by histopathological characteristics of the primary tumor and its lymph node metastases

BACKGROUND

Histopathological risk factors for survival stratification of surgically treated nodal positive prostate cancer patients are poorly defined as reflected by only one category for nodal metastases.

METHODS

We evaluated biochemical recurrence-free survival (RFS), disease-specific survival (DSS), and overall survival (OS) in 102 nodal positive, hormone treatment-naïve prostate cancer patients (median age: 65 years, range: 45-75 years; median follow-up 7.7 years, range: 1.0-15.9 years) who underwent radical prostatectomy and standardized extended lymphadenectomy.

RESULTS

A significant stratification was possible, with the Gleason score of the primary and virtually all nodal parameters favoring patients with better differentiated primaries and metastases, lower nodal tumor burden, and without extranodal extension of metastases. In multivariate analyses, diameter of the largest metastasis (< or =10 mm vs. >10 mm) was the strongest independent predictor for RFS (P < 0.001), DSS (P < 0.001), and OS (P < 0.001) with a more than quadrupled relative risk of cancer related deaths for patients with larger metastases (Hazard ratio: 4.2, Confidence interval: 2.0-8.9; 5-year RFS/DSS/OS: 18%/57%/54%). The highest 5-year survival rates were seen in patients with micrometastases only (RFS/DSS/OS: 47%/94%/94%).

CONCLUSION

The TNM classification's current allocation of only one category for nodal metastases in prostate cancers is unsatisfactory since subgroups with significantly different prognoses can be identified. The diameter of the patient's largest metastasis (< or =10 mm vs. >10 mm) should be used for substaging because of its independent prognostic value. The substage "micrometastasis only" is also useful in nodal positive prostate cancer since it designates the subgroup with the most favorable outcome.

Genome-wide linkage analysis of TMPRSS2-ERG fusion in familial prostate cancer

Fusion of the 5'-untranslated region of androgen-regulated TMPRSS2 promoter with ETS transcription factor family members is found frequently in prostate cancers, and recent work suggests that the most common TMPRSS2-ERG fusion is associated with an aggressive clinical phenotype compared with fusion-negative prostate cancer. Thus far, analysis of the fusion has been limited to sporadic cases of prostate cancer. In the current study, we explore for an enrichment of TMPRSS2-ERG fusion in familial prostate cancer. TMPRSS2-ERG fusion was identified using a break-apart fluorescence in situ hybridization assay on tissue microarrays. Presence of TMPRSS2-ERG fusion was associated with higher Gleason scores (P = 0.027). Of 75 patients with established history of prostate cancer, we detected the TMPRSS2-ERG fusion in 44 (59%) patients. Almost three quarters (73%) of fusion-positive patients accumulated within 16 specific families whereas only 27% were single fusion-positive cases within one family. Based on reported prevalence rates, we calculated a sibling recurrence risk ratio of up to 18.9. A subset (63%) of families with uniformly TMPRSS2-ERG-positive prostate cancer underwent a genome-wide linkage scan at 500 markers. This revealed several loci located on chromosomes #9, #18, and X that were suggestive of linkage to the TMPRSS2-ERG fusion-positive prostate cancer phenotype with linkage-of-disease scores up to 2.16 and nonparametric linkage scores up to 2.77. This suggests the presence of an inherited susceptibility to developing the TMPRSS2-ERG fusion. Given the association of TMPRSS2-ERG fusion and aggressive prostate cancer, close surveillance of relatives of patients with established fusion-positive prostate cancer or a family history of prostate cancer in general would be warranted.

Histopathological characteristics of lymph node metastases predict cancer-specific survival in node-positive prostate cancer

OBJECTIVE

To correlate the histopathological characteristics of lymph node metastases in prostate cancer with cancer-specific survival (CSS).

PATIENTS AND METHODS

The histopathological slides from 142 patients who had had a pelvic lymph node dissection for node-positive prostate cancer were reviewed. For each patient we recorded the number of lymph nodes removed, the number of positive nodes, the diameter of the largest metastasis and extranodal extension (ENE). The lymph node metastases were graded according to the Gleason system. These variables were correlated with CSS.

RESULTS

The mean age of the patients was 62.4 years and the mean preoperative prostate-specific antigen level was 40.2 ng/mL. The median follow-up was 77.5 months, and the median overall and CSS were 91 and 112 months, respectively. On univariable analysis the following variables correlated with poor CSS: a nodal Gleason score of >7 (hazard ratio 2.4, P < 0.001), a diameter of the largest metastasis of >3 mm (2.2, P = 0.025), more than two lymph node metastases (2.0, P = 0.003), and ENE in more than one lymph node (1.9, P = 0.014). Multivariable analysis showed only the nodal Gleason score and the diameter of the largest metastasis to be independent predictors of CSS (1.8, P = 0.021, and 2.2, P = 0.046, respectively).

CONCLUSION

The histopathological characteristics of lymph node metastases in prostate cancer have predictive value for the clinical outcome. The nodal Gleason score and the diameter of the largest metastasis are independent predictors of survival.

Cytology of metastatic prostate cancer following orchiectomy and antiandrogen therapy: a diagnostic challenge

Androgen deprivation therapy induces apoptosis and decreases both cell proliferation and angiogenesis in prostate adenocarcinoma. The molecular alterations following androgen ablation translate into unique cytologic features in both primary and metastatic prostate adenocarcinoma. We describe the cytologic appearance of metastatic prostate carcinoma following both surgical castration and androgen deprivation therapy.

TMPRSS2:ERG fusion-associated deletions provide insight into the heterogeneity of prostate cancer

Prostate cancer is a common and clinically heterogeneous disease with marked variability in progression. The recent identification of gene fusions of the 5'-untranslated region of TMPRSS2 (21q22.3) with the ETS transcription factor family members, either ERG (21q22.2), ETV1 (7p21.2), or ETV4 (17q21), suggests a mechanism for overexpression of the ETS genes in the majority of prostate cancers. In the current study using fluorescence in situ hybridization (FISH), we identified the TMPRSS2:ERG rearrangements in 49.2% of 118 primary prostate cancers and 41.2% of 18 hormone-naive lymph node metastases. The FISH assay detected intronic deletions between ERG and TMPRSS2 resulting in TMPRSS2:ERG fusion in 60.3% (35 of 58) of the primary TMPRSS2:ERG prostate cancers and 42.9% (3 of 7) of the TMPRSS2:ERG hormone-naive lymph node metastases. A significant association was observed between TMPRSS2:ERG rearranged tumors through deletions and higher tumor stage and the presence of metastatic disease involving pelvic lymph nodes. Using 100K oligonucleotide single nucleotide polymorphism arrays, a homogeneous deletion site between ERG and TMPRSS2 on chromosome 21q22.2-3 was identified with two distinct subclasses distinguished by the start point of the deletion at either 38.765 or 38.911 Mb. This study confirms that TMPRSS2:ERG is fused in approximately half of the prostate cancers through deletion of genomic DNA between ERG and TMPRSS2. The deletion as cause of TMPRSS2:ERG fusion is associated with clinical features for prostate cancer progression compared with tumors that lack the TMPRSS2:ERG rearrangement.

Collagen XXIII expression is associated with prostate cancer recurrence and distant metastases

PURPOSE

We had previously identified a new transmembrane collagen, type XXIII, in metastatic rat prostate carcinoma cells. The purpose of this study was to determine the expression of collagen XXIII in human prostate cancer and investigate its relationship with disease progression.

EXPERIMENTAL DESIGN

We investigated collagen XXIII expression in prostate cancer tissue and did a retrospective analysis of association with prostate-specific antigen (PSA)-defined disease recurrence. The presence of collagen XXIII in prostate cancer patient urine was also assessed before and after prostatectomy.

RESULTS

Collagen XXIII protein was detected at very low levels in benign prostate tissue and was significantly increased in prostate cancer. Distant metastases exhibited significantly higher collagen XXIII levels compared with either localized prostate cancer or regional (lymph node) metastases. Patients with high collagen XXIII levels had a 2.8-fold higher risk of PSA failure with median time to failure of 8.1 months, compared with low collagen XXIII patients with a median time to failure of 5 years. Multivariate Cox regression showed that the presence of collagen XXIII was significantly associated with time to PSA recurrence, independent of other clinical variables. Collagen XXIII was also detected in prostate cancer patient urine, with reduced levels after prostatectomy, indicating potential as a noninvasive fluid biomarker.

CONCLUSIONS

We present the first report demonstrating increased collagen XXIII expression in prostate cancer tissue. We show that collagen XXIII level is a significant independent predictor of PSA-defined disease recurrence, suggesting a potential role as a molecular biomarker of prostate cancer progression and metastasis.

TMPRSS2-ERG Fusion Prostate Cancer: An Early Molecular Event Associated With Invasion

Prostate cancer (PCA) is one of the most prevalent cancers and a major leading cause of morbidity and mortality in the Western world. The TMPRSS2-ERG fusion was recently identified as a common recurrent chromosomal aberration in this malignancy. In our study, we interrogated a broad spectrum of benign, precursor, and malignant prostatic lesions to assess the TMPRSS2-ERG fusion status using a multicolor interphase fluorescence in situ hybridization assay. Samples from hospital-based cohorts consisted of 237 clinically localized PCA, 34 hormone naive metastases, 9 hormone refractory metastases, 26 high grade prostatic intraepithelial neoplasia lesions, 15 samples of benign prostatic hyperplasia, 38 of proliferative inflammatory atrophy, and 47 of benign prostatic tissue. The TMPRSS2-ERG fusion was present in 48.5% of clinically localized PCA, 30% of hormone naive metastases, 33% of hormone refractory metastases, and in 19% of high grade prostatic intraepithelial neoplasia lesions in intermingling to cancer foci. Almost all these fusion positive cases show a homogenous distribution of the fusion pattern. In contrast, none of the other samples harbored this genetic aberration. If we consider the high incidence of PCA and the high frequency of this gene fusion, TMPRSS2-ERG is the most common genetic aberration so far described in human malignancies. Furthermore, its clinical application as a biomarker and ancillary diagnostic test is promising given its high specificity.

Molecular characterization of TMPRSS2-ERG gene fusion in the NCI-H660 prostate cancer cell line: a new perspective for an old model

Recent studies have established that a significant fraction of prostate cancers harbor a signature gene fusion between the 5' region of androgen-regulated TMPRSS2 and an ETS family transcription factor, most commonly ERG. Studies on the molecular mechanisms and functional consequences of this important chromosomal rearrangement are currently limited to the VCaP cell line derived from a vertebral bone metastasis of a hormone-refractory prostate tumor. Here we report on the NCI-H660 cell line, derived from a metastatic site of an extrapulmonary small cell carcinoma arising from the prostate. NCI-H660 harbors TMPRSS2-ERG fusion with a homozygous intronic deletion between TMPRSS2 and ERG. We demonstrate this by real-time quantitative polymerase chain reaction, a two-stage dual-color interphase fluorescence in situ hybridization (FISH) assay testing for TMPRSS2 and ERG break-aparts, and single-nucleotide polymorphism oligonucleotide arrays. The deletion is consistent with the common intronic deletion found on chromosome 21q22.2-3 in human prostate cancer samples. We demonstrate the physical juxtaposition of TMPRSS2 and ERG on the DNA level by fiber FISH. The androgen receptor-negative NCI-H660 cell line expresses ERG in an androgen-independent fashion. This in vitro model system has the potential to provide important pathobiologic insights into TMPRSS2-ERG fusion prostate cancer.

Prostate-specific membrane antigen expression as a predictor of prostate cancer progression

Distinguishing aggressive prostate cancer from indolent disease represents an important clinical challenge, because current therapy may lead to overtreatment of men with limited disease. The prostate-specific membrane antigen (PSMA) is a membrane-bound glycoprotein that is highly restricted to the prostate. Previously, studies analyzing the expression of PSMA have found an up-regulation in correlation with prostate cancer, particularly in advanced cancer. This association is ideal for an application as a prognostic marker. In the current study, we characterized PSMA expression in a high-risk cohort and evaluated its potential use as predictive marker of prostate-specific antigen (PSA) recurrence. PSMA expression was analyzed by immunohistochemistry using tissue microarrays composed of tumor samples from 450 patients. Protein intensity was recorded using a semiautomated quantitative microscope system (ACIS II; Clarient Chromavision Medical Systems, San Juan Capistrano, CA). PSMA expression levels differed significantly (P < .001) between benign prostatic tissue, localized prostate cancer, and lymph node metastases. Dividing the cohort into high- and low-PSMA expressing cancers based on the median area of positive staining, we found that high PSMA levels were associated with significant increase of PSA recurrence (P = .004). This was independent of clinical parameters such as lymph node tumor burden (lymph node density, >20%; P < .001), extraprostatic extension (P = .017), seminal vesicle invasion (P < .001), and high Gleason score (8-10, P = .006). In a multivariate model, PSMA expression and metastases to pelvic lymph nodes were significantly associated with time to PSA recurrence (HR, 1.4; 95% confidence interval, 1.1-2.8, P = .017; and hazard ratio, 5; 95% confidence interval, 2.6-9.7, P < .001, respectively). In summary, PSMA is independently associated with PSA recurrence in a high-risk cohort and thus might provide insight into the additional use of adjuvant therapy. Validation on other cohorts is required.