PROREPAIR-B: A Prospective Cohort Study of the Impact of Germline DNA Repair Mutations on the Outcomes of Patients With Metastatic Castration-Resistant Prostate Cancer

Current State of Personalized Genitourinary Cancer Radiotherapy in the Era of Precision Medicine

Radiation therapy plays a crucial role for the management of genitourinary malignancies, with technological advancements that have led to improvements in outcomes and decrease in treatment toxicities. However, better risk-stratification and identification of patients for appropriate treatments is necessary. Recent advancements in imaging and novel genomic techniques can provide additional individualized tumor and patient information to further inform and guide treatment decisions for genitourinary cancer patients. In addition, the development and use of targeted molecular therapies based on tumor biology can result in individualized treatment recommendations. In this review, we discuss the advances in precision oncology techniques along with current applications for personalized genitourinary cancer management. We also highlight the opportunities and challenges when applying precision medicine principles to the field of radiation oncology. The identification, development and validation of biomarkers has the potential to personalize radiation therapy for genitourinary malignancies so that we may improve treatment outcomes, decrease radiation-specific toxicities, and lead to better long-term quality of life for GU cancer survivors.

Epidemiology and genomics of prostate cancer in Asian men

Prostate cancer is a global health problem, but incidence varies considerably across different continents. Asia is traditionally considered a low-incidence area, but the incidence and mortality of prostate cancer have rapidly increased across the continent. Substantial differences in epidemiological features have been observed among different Asian regions, and incidence, as well as mortality-to-incidence ratio, is associated with the human development index. Prostate cancer mortality decreased in Japan and Israel from 2007 to 2016, but mortality has increased in Thailand, Kyrgyzstan and Uzbekistan over the same period. Genomic analyses have shown a low prevalence of ERG oncoprotein in the East Asian population, alongside a low rate of PTEN loss, high CHD1 enrichments and high FOXA1 alterations. Contributions from single-nucleotide polymorphisms to prostate cancer risk vary with ethnicity, but germline mutation rates of DNA damage repair genes in metastatic prostate cancer are comparable in Chinese and white patients from the USA and UK. Pharmacogenomic features of testosterone metabolism might contribute to disparities seen in the response to androgen deprivation between East Asian men and white American and European men. Overall, considerable diversity in epidemiology and genomics of prostate cancer across Asia defines disease characteristics in these populations, but studies in this area are under-represented in the literature. Taking into account this intracontinental and intercontinental heterogeneity, translational studies are required in order to develop ethnicity-specific treatment strategies.

SEOM clinical guidelines for the treatment of advanced prostate cancer (2020)

The treatment of advanced prostate cancer has evolved due to recent advances in molecular research and new drug development. Dynamic aberrations in the androgen receptor, DNA repair genes, PTEN-PI3K, and other pathways drive the behavior of advanced prostate cancer allowing a better selection of therapies in each patient. Tumor testing for BRCA1 and BRCA2 is recommended for patients with metastatic prostate cancer, also considering a broad panel to guide decisions and genetic counseling. In symptomatic metastatic patients, castration should be stared to palliate symptoms and prolong survival. In high-risk or high-volume metastatic hormone-naïve patients, castration should be combined with docetaxel, abiraterone, enzalutamide or apalutamide. Radiotherapy to the primary tumor combined with systemic therapy is recommended in low-volume mHNPC patients. In patients with non-metastatic castration-resistant tumors, risk stratification can define the frequency of imaging. Adding enzalutamide, darolutamide or apalutamide to these patients prolongs metastasis-free and overall survival, but potential adverse events need to be taken into consideration. The choice of docetaxel, abiraterone or enzalutamide for treating metastatic castration-resistant patients depends on previous therapies, with cabazitaxel being also recommended after docetaxel. Olaparib is recommended in BRCA1/BRCA2 mutated castration-resistant patients after progression on at least one new hormonal therapy. Aggressive variants of prostate cancer respond to platinum-based chemotherapy. To optimize treatment efficiency, oncologists should incorporate all of these advances into an overall therapeutic strategy.

Bayesian predictive model to assess BRCA2 mutational status according to clinical history: Early onset, metastatic phenotype or family history of breast/ovary cancer

BACKGROUND

Mutations of the BRCA2 gene are the most frequent alterations found in germline DNA from men with prostate cancer (PrCa), but clinical parameters that could better orientate for BRCA2 mutation screening need to be established.

METHODS

Germline DNA from 325 PrCa patients (median age at diagnosis: 57 years old) was screened for BRCA2 mutation. The mutation frequency was compared between three subgroups: patients with an age at diagnosis at 55 years old and under (Group I); a personal or family history of breast, uterine or ovarian cancer (Group II); or a metastatic disease (Group III). Frequency of BRCA2 mutations was established for each combination of phenotypes, and compared between patients meeting or not the criteria for each subgroup using Fisher's exact test. Mutual information, direct effect, elasticity and contribution to the mutational status of each phenotype, taking into account overlap between subgroups, were also estimated using Bayesian algorithms.

RESULTS

The proportion of BRCA2 mutation was 5.9% in Group I, 10.9% in Group II and 6.9% in Group III. The frequency of BRCA2 mutation was significantly higher among patients of Group II (p = .006), and reached 15.6% among patients of this group who presented a metastatic disease. Mutual information, direct effect, elasticity and contribution to the mutational status were the highest for phenotype II. Fifteen (71.4%) of the 21 BRCA2 mutation carriers had an aggressive form of the disease. Four (19%) of them died from PrCa after a median follow-up duration of 64.5 months.

CONCLUSIONS

Our results showed that a higher frequency of BRCA2 mutation carriers is observed, not only among PrCa patients with young onset or a metastatic disease, but also with a personal or a familial history of breast cancer.

Genomic Features and Classification of Homologous Recombination Deficient Pancreatic Ductal Adenocarcinoma

BACKGROUND AND AIMS

Homologous recombination deficiency (HRD) in pancreatic ductal adenocarcinoma (PDAC), remains poorly defined beyond germline (g) alterations in BRCA1, BRCA2, and PALB2.

METHODS

We interrogated whole genome sequencing (WGS) data on 391 patients, including 49 carriers of pathogenic variants (PVs) in gBRCA and PALB2. HRD classifiers were applied to the dataset and included (1) the genomic instability score (GIS) used by Myriad's MyChoice HRD assay; (2) substitution base signature 3 (SBS3); (3) HRDetect; and (4) structural variant (SV) burden. Clinical outcomes and responses to chemotherapy were correlated with HRD status.

RESULTS

Biallelic tumor inactivation of gBRCA or PALB2 was evident in 43 of 49 germline carriers identifying HRD-PDAC. HRDetect (score ≥0.7) predicted gBRCA1/PALB2 deficiency with highest sensitivity (98%) and specificity (100%). HRD genomic tumor classifiers suggested that 7% to 10% of PDACs that do not harbor gBRCA/PALB2 have features of HRD. Of the somatic HRDetect^hi cases, 69% were attributed to alterations in BRCA1/2, PALB2, RAD51C/D, and XRCC2, and a tandem duplicator phenotype. TP53 loss was more common in BRCA1- compared with BRCA2-associated HRD-PDAC. HRD status was not prognostic in resected PDAC; however in advanced disease the GIS (P = .02), SBS3 (P = .03), and HRDetect score (P = .005) were predictive of platinum response and superior survival. PVs in gATM (n = 6) or gCHEK2 (n = 2) did not result in HRD-PDAC by any of the classifiers. In 4 patients, BRCA2 reversion mutations associated with platinum resistance.

CONCLUSIONS

Germline and parallel somatic profiling of PDAC outperforms germline testing alone in identifying HRD-PDAC. An additional 7% to 10% of patients without gBRCA/PALB2 mutations may benefit from DNA damage response agents.

Hong Kong Urological Association-Hong Kong Society of Uro-Oncology consensus statements on the management of advanced prostate cancer-2019 Updates

BACKGROUND

To update the Hong Kong Urological Association-Hong Kong Society of Uro-Oncology consensus statements on the management of advanced prostate cancer, the same panelists as in the previous consensus panel held a series of meetings to discuss updated clinical evidence and experiences.

METHODS

The previous consensus statements were retained, deleted, or revised, and new statements were added. At the final meeting, all statements were reviewed and amended as appropriate, followed by panel voting.

RESULTS

There were significant changes and additions to the previous consensus statements, primarily driven by the advances in androgen receptor signaling inhibitors, treatment sequencing in metastatic castration-resistant prostate cancer, and increasing recognition of oligometastatic prostate cancer since the introduction of prostate-specific membrane antigen positron emission tomography. In this update, a total of 59 consensus statements were accepted and established.

CONCLUSIONS

The consensus panel updated consensus statements on the management of advanced prostate cancer, aiming to allow physicians in the region to keep abreast of the recent evidence on optimal clinical practices.

Changing the History of Prostate Cancer with New Targeted Therapies

The therapeutic landscape of metastatic castration-resistant prostate cancer (mCRPC) is changing due to the emergence of new targeted therapies for the treatment of different molecular subtypes. Some biomarkers are described as potential molecular targets different from classic androgen receptors (AR). Approximately 20-25% of mCRPCs have somatic or germline alterations in DNA repair genes involved in homologous recombination. These subtypes are usually associated with more aggressive disease. Inhibitors of the enzyme poly ADP ribose polymerase (PARPi) have demonstrated an important benefit in the treatment of these subtypes of tumors. However, tumors that resistant to PARPi and wildtype BRCA tumors do not benefit from these therapies. Recent studies are exploring drug combinations with phosphatidylinositol-3-kinase (PI3K) or protein kinase B (AKT) inhibitors, as mechanisms to overcome resistance or to induce BRCAness and synthetic lethality. This article reviews various different novel strategies to improve outcomes in patients with prostate cancer.

Cabazitaxel versus abiraterone or enzalutamide in poor prognosis metastatic castration-resistant prostate cancer: a multicentre, randomised, open-label, phase II trial

BACKGROUND

Treatment of poor prognosis metastatic castration-resistant prostate cancer (mCRPC) includes taxane chemotherapy and androgen receptor pathway inhibitors (ARPI). We sought to determine optimal treatment in this setting.

PATIENTS AND METHODS

This multicentre, randomised, open-label, phase II trial recruited patients with ARPI-naive mCRPC and poor prognosis features (presence of liver metastases, progression to mCRPC after <12 months of androgen deprivation therapy, or ≥4 of 6 clinical criteria). Patients were randomly assigned 1 : 1 to receive cabazitaxel plus prednisone (group A) or physician's choice of enzalutamide or abiraterone plus prednisone (group B) at standard doses. Patients could cross over at progression. The primary endpoint was clinical benefit rate for first-line treatment (defined as prostate-specific antigen response ≥50%, radiographic response, or stable disease ≥12 weeks).

RESULTS

Ninety-five patients were accrued (median follow-up 21.9 months). First-line clinical benefit rate was greater in group A versus group B (80% versus 62%, P = 0.039). Overall survival was not different between groups A and B (median 37.0 versus 15.5 months, hazard ratio (HR) = 0.58, P = 0.073) nor was time to progression (median 5.3 versus 2.8 months, HR = 0.87, P = 0.52). The most common first-line treatment-related grade ≥3 adverse events were neutropenia (cabazitaxel 32% versus ARPI 0%), diarrhoea (9% versus 0%), infection (9% versus 0%), and fatigue (7% versus 5%). Baseline circulating tumour DNA (ctDNA) fraction above the cohort median and on-treatment ctDNA increase were associated with shorter time to progression (HR = 2.38, P < 0.001; HR = 4.03, P < 0.001). Patients with >30% ctDNA fraction at baseline had markedly shorter overall survival than those with undetectable ctDNA (HR = 38.22, P < 0.001).

CONCLUSIONS

Cabazitaxel was associated with a higher clinical benefit rate in patients with ARPI-naive poor prognosis mCRPC. ctDNA abundance was prognostic independent of clinical features, and holds promise as a stratification biomarker.

Resistance to second-generation androgen receptor antagonists in prostate cancer

The introduction of second-generation androgen receptor antagonists (SG-ARAs) has greatly impacted the treatment of metastatic prostate cancer, providing tolerable and efficacious alternatives to chemotherapy. SG-ARAs provide similar therapeutic benefit to abiraterone, a potent CYP17 inhibitor, and do not require the co-administration of prednisone. Despite considerable improvements in clinical outcomes in the settings of both castration sensitivity and castration resistance, the durability of clinical response to the SG-ARAs enzalutamide, apalutamide and darolutamide, similar to abiraterone, is limited by inevitable acquired resistance. Genomic aberrations that confer resistance to SG-ARAs or provide potential alternative treatment modalities have been identified in numerous studies, including alterations of the androgen receptor, DNA repair, cell cycle, PI3K-AKT-mTOR and Wnt-β-catenin pathways. To combat resistance, researchers have explored approaches to optimizing the utility of available treatments, as well as the use of alternative agents with a variety of targets, including AR-V7, AKT, EZH2 and HIF1α. Ongoing research to establish predictive biomarkers for the treatment of tumours with resistance to SG-ARAs led to the approval of the PARP inhibitors olaparib and rucaparib in pre-treated metastatic castration-resistant prostate cancer. The results of ongoing studies will help to shape precision medicine in prostate cancer and further optimize treatment paradigms to maximize clinical outcomes.

Prostate cancer and PARP inhibitors: progress and challenges

Despite survival improvements achieved over the last two decades, prostate cancer remains lethal at the metastatic castration-resistant stage (mCRPC) and new therapeutic approaches are needed. Germinal and/or somatic alterations of DNA-damage response pathway genes are found in a substantial number of patients with advanced prostate cancers, mainly of poor prognosis. Such alterations induce a dependency for single strand break reparation through the poly(adenosine diphosphate-ribose) polymerase (PARP) system, providing the rationale to develop PARP inhibitors. In solid tumors, the first demonstration of an improvement in overall survival was provided by olaparib in patients with mCRPC harboring homologous recombination repair deficiencies. Although this represents a major milestone, a number of issues relating to PARP inhibitors remain. This timely review synthesizes and discusses the rationale and development of PARP inhibitors, biomarker-based approaches associated and the future challenges related to their prescription as well as patient pathways.

Olaparib for the treatment of metastatic prostate cancer

Recent innovations in the treatment of metastatic prostate cancer have improved patient outcomes. Nonetheless, this disease remains fatal and additional treatment approaches are needed. Greater understanding of the molecular landscape of metastatic prostate cancer has revealed recurrent alterations in key pathways amenable to therapeutic targeting. One such pathway is DNA repair, particularly alterations in genes directly or indirectly associated with homologous recombination repair found in up to one-quarter of patients with metastatic castrate-resistant prostate cancer (mCRPC). Olaparib, an inhibitor of poly-ADP-ribose polymerase, has recently gained approval for the treatment of mCRPC harboring alterations in homologous recombination repair genes. This review will provide a summary of evidence regarding PARP inhibition in the treatment of mCRPC, with a specific focus on olaparib.

Attenuation of SRC Kinase Activity Augments PARP Inhibitor-mediated Synthetic Lethality in BRCA2-altered Prostate Tumors

PURPOSE

Alterations in DNA damage repair (DDR) pathway genes occur in 20%-25% of men with metastatic castration-resistant prostate cancer (mCRPC). Although PARP inhibitors (PARPis) have been shown to benefit men with mCRPC harboring DDR defects due to mutations in BRCA1/2 and ATM, additional treatments are necessary because the effects are not durable.

EXPERIMENTAL DESIGN

We performed transcriptomic analysis of publicly available mCRPC cases, comparing BRCA2 null with BRCA2 wild-type. We generated BRCA2-null prostate cancer cells using CRISPR/Cas9 and treated these cells with PARPis and SRC inhibitors. We also assessed the antiproliferative effects of combination treatment in 3D prostate cancer organoids.

RESULTS

We observed significant enrichment of the SRC signaling pathway in BRCA2-altered mCRPC. BRCA2-null prostate cancer cell lines had increased SRC phosphorylation and higher sensitivity to SRC inhibitors (e.g., dasatinib, bosutinib, and saracatinib) relative to wild-type cells. Combination treatment with PARPis and SRC inhibitors was antiproliferative and had a synergistic effect in BRCA2-null prostate cancer cells, mCRPC organoids, and Trp53/Rb1-null prostate cancer cells. Inhibition of SRC signaling by dasatinib augmented DNA damage in BRCA2-null prostate cancer cells. Moreover, SRC knockdown increased PARPi sensitivity in BRCA2-null prostate cancer cells.

CONCLUSIONS

This work suggests that SRC activation may be a potential mechanism of PARPi resistance and that treatment with SRC inhibitors may overcome this resistance. Our preclinical study demonstrates that combining PARPis and SRC inhibitors may be a promising therapeutic strategy for patients with BRCA2-null mCRPC.

Differential treatment outcomes in BRCA1/2-, CDK12-, and ATM-mutated metastatic castration-resistant prostate cancer

BACKGROUND

DNA damage repair mutations (DDRm) are common in patients with metastatic castration-resistant prostate cancer (mCRPC). The optimal standard therapy for this population is not well described.

METHODS

A multi-institutional, retrospective study of patients with mCRPC and DDRm was conducted. Patient data, including systemic therapies and responses, were collected. The decline in prostate-specific antigen ≥ 50% from baseline (PSA50) and overall survival (OS) from the treatment start were compared by mutation and treatment type. A multivariable Cox proportional hazards model for OS was created that controlled for DDRm, first-line treatment received for mCRPC, and clinical factors.

RESULTS

The most common DDRm observed among 149 men with mCRPC were BRCA1/2 (44%), CDK12 (32%), and ATM (15%). The majority received first-line abiraterone (40%) or enzalutamide (30%). The PSA50 rate with first-line abiraterone was lower for CDK12 (52%) than BRCA1/2 (89%; P = .02). After first-line abiraterone or enzalutamide, the median OS was longest with second-line carboplatin-chemotherapy (38 months) in comparison with abiraterone or enzalutamide (33 months), docetaxel (17 months), or cabazitaxel (11 months; P = .02). PSA50 responses to carboplatin-based chemotherapy were higher for BRCA1/2 (79%) than ATM (14%; P = .02) or CDK12 (38%; P = .08). In a multivariable analysis, neither the specific DDRm type nor the first-line treatment was associated with improved OS.

CONCLUSIONS

Responses to standard therapies were generally superior in patients with BRCA1/2 mutations and inferior in patients with ATM or CDK12 mutations. The DDRm type did not independently predict OS. After progression on first-line abiraterone or enzalutamide, carboplatin-based chemotherapy was associated with the longest OS. These findings may inform treatment discussions and clinical trial design and require prospective validation.

DNA damage repair gene mutation testing and genetic counseling in men with/without prostate cancer: a systematic review

Background: Ongoing clinical trials are investigating PARP inhibitors to target the DNA damage repair (DDR) pathway in prostate cancer. DDR mutation screening will guide treatment strategy and assess eligibility for clinical trials. Materials & methods: This systematic review estimated the rate of DDR mutation testing or genetic counseling among men with or at risk of prostate cancer. Results: From 6856 records, one study fulfilled the inclusion criteria and described men undiagnosed with prostate cancer with a family history of BRCA1/2 mutation who received DDR mutation testing. Conclusion: With only one study included in this first systematic review of DDR mutation testing or genetic counseling in men with or at risk of prostate cancer, more research is warranted.

Association between BRCA2 alterations and intraductal and cribriform histologies in prostate cancer

BACKGROUND

Intraductal (IDC) and cribriform (CRIB) histologies in prostate cancer have been associated with germline BRCA2 (gBRCA2) mutations in small retrospective series, leading to the recommendation of genetic testing for patients with IDC in the primary tumour.

PATIENTS AND METHODS

To examine the association of gBRCA2 mutations and other tumour molecular features with IDC and/or cribriform (CRIB) histologies, we conducted a case-control study in which primary prostate tumours from 58 gBRCA2 carriers were matched (1:2) by Gleason Grade Group and specimen type to 116 non-carriers. Presence/absence of IDC and CRIB morphologies was established by two expert uropathologists blinded to gBRCA2 status. Fluorescent in-situ hybridization (FISH) and next-generation sequencing (NGS) were used to detect BRCA2 alterations, PTEN deletions and TMPRSS2-ERG fusions. Chi-squared tests were used to compare the frequency of IDC and CRIB in gBRCA2 carriers and controls and to assess associations with other variables. Logistic regression models were constructed to identify independent factors associated with both histology patterns.

RESULTS

No significant differences between gBRCA2 carriers and non-carriers were observed in the prevalence of IDC (36% gBRCA2 versus 50% non-carriers, p = 0.085) or CRIB (53% gBRCA2 versus 43% non-carriers p = 0.197) patterns. However, IDC histology was independently associated with bi-allelic BRCA2 alterations (OR 4.3, 95%CI 1.1-16.2) and PTEN homozygous loss (OR 5.2, 95%CI 2.1-13.1). CRIB morphology was also independently associated with bi-allelic BRCA2 alterations (OR 5.6, 95%CI 1.7-19.3).

CONCLUSIONS

While we found no association between gBRCA2 mutations and IDC or CRIB histologies, bi-allelic BRCA2 loss in primary prostate tumours was significantly associated with both variant morphologies, independently of other clinical-pathologic factors.

Tumor protein expression of the DNA repair gene BRCA1 and lethal prostate cancer

DNA repair genes are commonly altered in metastatic prostate cancer, but BRCA1 mutations are rare. Preliminary studies suggest that higher tumor expression of the BRCA1 protein may be associated with worse prognosis. We undertook a prospective study among men with prostate cancer in the Health Professionals Follow-up Study and evaluated BRCA1 via immunohistochemical staining on tissue microarrays. BRCA1 was expressed in 60 of 589 tumors. Prevalence of BRCA1 positivity was 43% in the 14 men with metastases at diagnosis compared with 9% in non-metastatic tumors [difference, 33 percentage points; 95% confidence interval (CI), 7-59]. BRCA1-positive tumors had 2.16-fold higher Ki-67 proliferative indices (95% CI, 1.18-3.95), higher tumor aneuploidy as predicted from whole-transcriptome profiling, and higher Gleason scores. Among the 575 patients with non-metastatic disease at diagnosis, we evaluated the association between BRCA1 expression and development of lethal disease (metastasis or cancer-specific death, 69 events) during long-term follow-up (median, 18.3 years). A potential weak association of BRCA1 positivity with lethal disease (hazard ratio, 1.61; 95% CI, 0.82-3.15) was attenuated when adjusting for age, Gleason score and clinical stage (hazard ratio, 1.11; 95% CI, 0.54-2.29). In summary, BRCA1 protein expression is a feature of more proliferative and more aneuploid prostate tumors and is more common in metastatic disease. While not well suited as a prognostic biomarker in primary prostate cancer, BRCA1 protein expression may be most relevant in advanced disease.

Early-onset prostate cancer is associated with increased risks of disease progression and cancer-specific mortality

OBJECTIVE

Prostate cancer (PCa) incidence has stabilized but not in patients at a young age. We assessed patient characteristics and disease progression in early-onset PCa.

METHODS

A retrospective cohort of 28,039 newly diagnosed PCa patients aged ≥35 years was constructed using the Taiwan Cancer Registry in 2008-2016. Patients were categorized by age at diagnosis (≤54, 55-59, 60-69, 70-74, and ≥75 years). The clinical stage at diagnosis, Gleason score, prostate-specific antigen level at diagnosis, Charlson's comorbidity index, and primary and secondary treatments for PCa were included in the analysis. All-cause mortality and prostate cancer-specific mortality (PCSM) were reported. Hazard ratios (HRs) and 95% confidence intervals (CIs) estimating the risks of death and of receiving secondary cancer treatment were generated by Cox hazard models.

RESULTS

In patients aged ≤54, 55-59, and 60-69 years, about 60% of them in each group were classified into the high-risk, very high-risk, or metastatic group. However, young patients ≤54 years had a higher risk of PCSM than patients aged 60-69 years (HR = 1.22; 95% CI = 1.10-1.49). This trend of an increased risk in PCSM remained for high-risk, very high-risk, or metastatic patients (HR = 1.24; 95% CI = 1.01-1.51), but not in low- or intermediate-risk patients. Besides, young patients diagnosed with high-risk diseases had the highest risk of receiving secondary cancer treatment within 180 days after completing primary treatment among all age groups (HR = 1.32; 95% CI = 1.07-1.63).

CONCLUSIONS

PCa arising in young patients ≤54 years of age, especially those with a high risk or metastatic form, might be more aggressive than that in other age groups.

Genetic aberrations in DNA repair pathways: a cornerstone of precision oncology in prostate cancer

Over the past years, several studies have demonstrated that defects in DNA damage response and repair (DDR) genes are present in a significant proportion of patients with prostate cancer. These alterations, particularly mutations in BRCA2, are known to be associated with an increased risk of developing prostate cancer and more aggressive forms of the disease. There is growing evidence that certain DDR gene aberrations confer sensitivity to poly-(ADP ribose) polymerase inhibitors and/or platinum chemotherapy, while other defects might identify cases that are more likely to benefit from immune checkpoint inhibition. The potential prognostic impact and relevance for treatment selection together with the decreasing costs and broader accessibility to next-generation sequencing have already resulted in the increased frequency of genetic profiling of prostate tumours. Remarkably, almost half of all DDR genetic defects can occur in the germline, and prostate cancer patients identified as mutation carriers, as well as their families, will require appropriate genetic counselling. In this review, we summarise the current knowledge regarding the biology and clinical implications of DDR defects in prostate cancer, and outline how this evidence is prompting a change in the treatment landscape of the disease.

Genomic Testing in Patients with Metastatic Castration-resistant Prostate Cancer: A Pragmatic Guide for Clinicians

CONTEXT

Genomic testing is becoming increasingly important in patients with advanced prostate cancer (PC) and is being incorporated in clinical practice to guide treatment.

OBJECTIVE

To review the current understanding of genomic alterations and the status of genomic testing in patients with metastatic castration-resistant PC (mCRPC), and the potential use of genomic tests in clinical practice.

EVIDENCE ACQUISITION

We reviewed recent publications (past 15 yr) from PubMed, proceedings of scientific conferences, and published guidelines. Reports on mCRPC in the following areas were selected: development, testing, and validation of techniques for identifying genomic alterations; molecular characterization; and trials of genetically targeted therapies.

EVIDENCE SYNTHESIS

mCRPC tumors harbor molecular alterations that are possible targets for treatment, and a number of therapies are in development to exploit these alterations (eg, PD-1 inhibitors, PARP inhibitors, tyrosine kinase inhibitors). Next-generation sequencing of DNA from tumor tissue can identify somatic alterations that would not be identified by germline testing. Work is ongoing to evaluate the use of less invasive somatic testing methods (eg, sequencing of cell-free circulating tumor DNA). Current international guidelines recommend germline and/or somatic testing for men with advanced and/or high-risk PC regardless of family history to identify those with homologous recombination repair gene mutations or mismatch repair defects/microsatellite instability who may be eligible for treatment with a PARP inhibitor or pembrolizumab, respectively.

CONCLUSIONS

Genomic testing for mCRPC may provide information on prognostic, predictive, and resistance biomarkers. Although the incorporation of testing into clinical practice remains challenging, routine genomic testing of men with advanced PC is recommended to guide management and treatment decisions.

PATIENT SUMMARY

Similar to many cancers, prostate cancer is caused by defects in the cancer's DNA, which are called genetic or genomic defects. New treatments targeting these defects are approved for metastatic castration-resistant prostate cancer. Specific new tests are under development to detect these potentially treatable genetic defects.

New Prognostic Biomarkers in Metastatic Castration-Resistant Prostate Cancer

Prostate cancer is one of the most frequent cancers in men and is a common cause of cancer-related death. Despite significant progress in the diagnosis and treatment of this tumor, patients who relapse after radical treatments inevitably develop metastatic disease. Patient stratification is therefore key in this type of cancer, and there is an urgent need for prognostic biomarkers that can define patients' risk of cancer-related death. In the last 10 years, multiple prognostic factors have been identified and studied. Here, we review the literature available and discuss the most common aberrant genomic pathways in metastatic castration-resistant prostate cancer shown to have a prognostic relevance in this setting.

BRCA2, ATM, and CDK12 Defects Differentially Shape Prostate Tumor Driver Genomics and Clinical Aggression

PURPOSE

DNA damage repair (DDR) defects are common across cancer types and can indicate therapeutic vulnerability. Optimal exploitation of DDR defects in prostate cancer requires new diagnostic strategies and a better understanding of associated clinical genomic features.

EXPERIMENTAL DESIGN

We performed targeted sequencing of 1,615 plasma cell-free DNA samples from 879 patients with metastatic prostate cancer. Depth-based copy-number calls and heterozygous SNP imbalance were leveraged to expose DDR-mutant allelic configuration and categorize mechanisms of biallelic loss. We used split-read structural variation analysis to characterize tumor suppressor rearrangements. Patient-matched archival primary tissue was analyzed identically.

RESULTS

BRCA2, ATM, and CDK12 were the most frequently disrupted DDR genes in circulating tumor DNA (ctDNA), collectively mutated in 15% of evaluable cases. Biallelic gene disruption via second somatic alteration or mutant allele-specific imbalance was identified in 79% of patients. A further 2% exhibited homozygous BRCA2 deletions. Tumor suppressors TP53, RB1, and PTEN were controlled via disruptive chromosomal rearrangements in BRCA2-defective samples, but via oncogene amplification in context of CDK12 defects. TP53 mutations were rare in cases with ATM defects. DDR mutations were re-detected across 94% of serial ctDNA samples and in all available archival primary tissues, indicating they arose prior to metastatic progression. Loss of BRCA2 and CDK12, but not ATM, was associated with poor clinical outcomes.

CONCLUSIONS

BRCA2, ATM, and CDK12 defects are each linked to distinct prostate cancer driver genomics and aggression. The consistency of DDR status in longitudinal samples and resolution of allelic status underscores the potential for ctDNA as a diagnostic tool.

Genetic counseling in prostate cancer: How to implement it in daily clinical practice?

Prostate cancer plays an undeniably prominent role in public health in our days and health systems. Its epidemiological impact is quantitatively very close to that of other tumors such as colon cancer and breast cancer, in which genetic counseling is part of their routine clinical practice, both in the initial evaluation and in the selection of therapeutic strategies. Hereditary cancer syndromes, breast/ovarian and Lynch syndrome are part of genetic counseling in these tumors. Currently, we also know that they can be associated to prostate cancer. The time has come to implement genetic counseling in prostate cancer from the earliest stages of its approach, from initial suspicion to the most advanced tumors. We present an updated review carried out by our interdisciplinary working group on scientific literature, clinical practice guidelines and consensus documents, aimed at the creation and drafting of a'Protocol for genetic counseling in prostate cancer' for the study of germline, with easy application in different healthcare settings. This protocol is currently being implemented in our routine practice and provides answers to 3 specific questions: Who should receive genetic counseling for prostate cancer? Which gene panel should be analyzed? How should counseling be done according to the results obtained? Other aspects about who should perform genetic counseling, ethical considerations and regulations are also collected.

To treat or not to treat: is it acceptable to avoid active therapies in advanced prostate cancer today?

Introduction: Recently, there has been a paradigm shift in the treatment of advanced prostate cancer (PCa) because the approval of a number of new agents has significantly improved overall survival. However, as PCa is a heterogeneous disease that may be more or less aggressive and patients may be more or less responsive to treatment, it is often debated whether or not it is acceptable to avoid active therapies.Areas covered: This review discusses different settings of advanced PCa.Expert opinion: In metastatic castration-resistant PCa, it is unethical not to use active treatments but the use of both androgen receptor targeting agents (ARTA) in sequence should be avoided in most patients and the use of the available agents for fourth-line treatment or beyond should only be considered for highly selected patients. In metastatic hormone-sensitive PCa, patients with de novo disease should receive one additional agent in combination with androgen deprivation therapy (ADT), whereas patients in relapse should be managed with ADT alone. In non-metastatic castration-resistant prostate cancer (PCa), all patients with a PSA doubling time of ≤6 months should receive one ARTA, whereas the others might wait until there is an acceleration in the kinetics of their PSA levels.

Survival with Olaparib in Metastatic Castration-Resistant Prostate Cancer

BACKGROUND

We previously reported that olaparib led to significantly longer imaging-based progression-free survival than the physician's choice of enzalutamide or abiraterone among men with metastatic castration-resistant prostate cancer who had qualifying alterations in homologous recombination repair genes and whose disease had progressed during previous treatment with a next-generation hormonal agent. The results of the final analysis of overall survival have not yet been reported.

METHODS

In an open-label, phase 3 trial, we randomly assigned patients in a 2:1 ratio to receive olaparib (256 patients) or the physician's choice of enzalutamide or abiraterone plus prednisone as the control therapy (131 patients). Cohort A included 245 patients with at least one alteration in BRCA1, BRCA2, or ATM, and cohort B included 142 patients with at least one alteration in any of the other 12 prespecified genes. Crossover to olaparib was allowed after imaging-based disease progression for patients who met certain criteria. Overall survival in cohort A, a key secondary end point, was analyzed with the use of an alpha-controlled, stratified log-rank test at a data maturity of approximately 60%. The primary and other key secondary end points were reported previously.

RESULTS

The median duration of overall survival in cohort A was 19.1 months with olaparib and 14.7 months with control therapy (hazard ratio for death, 0.69; 95% confidence interval [CI], 0.50 to 0.97; P = 0.02). In cohort B, the median duration of overall survival was 14.1 months with olaparib and 11.5 months with control therapy. In the overall population (cohorts A and B), the corresponding durations were 17.3 months and 14.0 months. Overall, 86 of 131 patients (66%) in the control group crossed over to receive olaparib (56 of 83 patients [67%] in cohort A). A sensitivity analysis that adjusted for crossover to olaparib showed hazard ratios for death of 0.42 (95% CI, 0.19 to 0.91) in cohort A, 0.83 (95% CI, 0.11 to 5.98) in cohort B, and 0.55 (95% CI, 0.29 to 1.06) in the overall population.

CONCLUSIONS

Among men with metastatic castration-resistant prostate cancer who had tumors with at least one alteration in BRCA1, BRCA2, or ATM and whose disease had progressed during previous treatment with a next-generation hormonal agent, those who were initially assigned to receive olaparib had a significantly longer duration of overall survival than those who were assigned to receive enzalutamide or abiraterone plus prednisone as the control therapy, despite substantial crossover from control therapy to olaparib. (Funded by AstraZeneca and Merck Sharp and Dohme; PROfound ClinicalTrials.gov number, NCT02987543.).

Report From the International Society of Urological Pathology (ISUP) Consultation Conference on Molecular Pathology of Urogenital Cancers. I. Molecular Biomarkers in Prostate Cancer

The combined clinical and molecular heterogeneity of prostate cancer necessitates the use of prognostic, predictive, and diagnostic biomarkers to assist the clinician with treatment selection. The pathologist plays a critical role in guiding molecular biomarker testing in prostate cancer and requires a thorough knowledge of the current testing options. In the setting of clinically localized prostate cancer, prognostic biomarkers such as Ki-67 labeling, PTEN loss or mRNA-based genomic signatures can be useful to help determine whether definitive therapy is required. In the setting of advanced disease, predictive biomarkers, such as the presence of DNA repair deficiency mediated by BRCA2 loss or mismatch repair gene defects, may suggest the utility of poly-ADP ribosylase inhibition or immune checkpoint blockade. Finally, androgen receptor-related biomarkers or diagnostic biomarkers indicating the presence of small cell neuroendocrine prostate cancer may help guide the use of androgen receptor signaling inhibitors and chemotherapy. In this review, we examine the current evidence for several prognostic, predictive and diagnostic tissue-based molecular biomarkers in prostate cancer management. For each assay, we summarize a recent survey of the International Society of Urology Pathology (ISUP) members on current testing practices and include recommendations for testing that emerged from the ISUP Working Group on Molecular Pathology of Prostate Cancer and the 2019 Consultation Conference on Molecular Pathology of Urogenital Cancers.

Prevalence of comprehensive DNA damage repair gene germline mutations in Chinese prostate cancer patients

Germline DNA damage repair (DDR) deficiency has been associated with increased cancer risk, poor prognosis and therapeutic opportunity for prostate cancer (PCa) patients. However, the landscape of germline mutations in PCa covering comprehensive DDR genes has not been reported. We performed whole-exome sequencing in 246 patients who meet the National Cancer Center Network guidelines for genetic testing and analyzed variants in 276 DDR genes, which was from the Cancer Genome Atlas. A total of 79 deleterious germline alterations in 60 DDR genes were identified in 31% (76/246) patients. Mutations were found in nine DDR pathways, including 11.8% men in homologous recombination repair (HR) pathways, 2.4% men in mismatch repair (MMR) pathway and 16.7% (41/246) patients in non-HR/MMR pathways. In HRR and MMR pathways, mutations were mostly identified in BRCA2 (5.3%), HFM1 (0.8%), ZSWIM7 (0.8%), MSH2 (0.8%) and MSH3 (0.8%). When compared with the cancer-free cohort, POLN and POLG conferred high risk to PCa with odds ratio 6.9 and 20.5, respectively. We provided a comprehensive view of germline DDR gene mutations in PCa patients. We also identified two potential PCa predisposition genes: POLN and POLG, which have not been reported in the Western population, confirming the necessity of customizing a multigene panel for Chinese PCa patients.

Genetic biomarkers to guide poly(ADP-ribose) polymerase inhibitor precision treatment of prostate cancer

Precision therapy for a subgroup of genetically defined metastatic castration-resistant prostate cancer patients may become a reality in the near future. DNA damage repair gene mutated prostate cancer might be vulnerable to treatment with PARP inhibitors (PARPi). PARPi clinical trials for prostate cancer investigate both germline and somatic genomic alterations of 43 genes for the applicability as genomic biomarker of PARPi sensitivity. Clinical trials with preliminary results show that BRCA2 and BRCA1, but also ATM, additionally BRIP1, FANCA, CDK12 and PALB2 may affect clinical end points, and may be potential candidates for genome-guided patient selection in PARPi treatment of prostate cancer.

Activity of Platinum-Based Chemotherapy in Patients With Advanced Prostate Cancer With and Without DNA Repair Gene Aberrations

IMPORTANCE

DNA repair gene aberrations occur in 20% to 30% of patients with castration-resistant prostate cancer (CRPC), and some of these aberrations have been associated with sensitivity to poly(ADP-ribose) polymerase (PARP) inhibition platinum-based treatments. However, previous trials assessing platinum-based treatments in patients with CRPC have mostly included a biomarker-unselected population; therefore, efficacy in these patients is unknown.

OBJECTIVE

To characterize the antitumor activity of platinum-based therapies in men with CRPC with or without DNA repair gene alterations.

DESIGN, SETTING, AND PARTICIPANTS

In this case series, data from 508 patients with CRPC treated with platinum-based therapy were collected from 25 academic centers from 12 countries worldwide. Patients were grouped by status of DNA repair gene aberrations (ie, cohort 1, present; cohort 2, not detected; and cohort 3, not tested). Data were collected from January 1986 to December 2018. Data analysis was performed in 2019, with data closure in April 2019.

EXPOSURE

Treatment with platinum-based compounds either as monotherapy or combination therapy.

MAIN OUTCOMES AND MEASURES

The primary end points were as follows: (1) antitumor activity of platinum-based therapy, defined as a decrease in prostate-specific antigen (PSA) level of at least 50% and/or radiological soft tissue response in patients with measurable disease and (2) the association of response with the presence or absence of DNA repair gene aberrations.

RESULTS

A total of 508 men with a median (range) age of 61 (27-88) years were included in this analysis. DNA repair gene aberrations were present in 80 patients (14.7%; cohort 1), absent in 98 (19.3%; cohort 2), and not tested in 330 (65.0%; cohort 3). Of 408 patients who received platinum-based combination therapy, 338 patients (82.8%) received docetaxel, paclitaxel, or etoposide, and 70 (17.2%) received platinum-based combination treatment with another partner. A PSA level decrease of at least 50% was seen in 33 patients (47.1%) in cohort 1 and 26 (36.1%) in cohort 2 (P = .20). In evaluable patients, soft tissue responses were documented in 28 of 58 patients (48.3%) in cohort 1 and 21 of 67 (31.3%) in cohort 2 (P = .07). In the subgroup of 44 patients with BRCA2 gene alterations, PSA level decreases of at least 50% were documented in 23 patients (63.9%) and soft tissue responses in 17 of 34 patients (50.0%) with evaluable disease. In cohort 3, PSA level decreases of at least 50% and soft tissue responses were documented in 81 of 284 patients (28.5%) and 38 of 185 patients (20.5%) with evaluable disease, respectively.

CONCLUSIONS AND RELEVANCE

In this study, platinum-based treatment was associated with relevant antitumor activity in a biomarker-positive population of patients with advanced prostate cancer with DNA repair gene aberrations. The findings of this study suggest that platinum-based treatment may be considered an option for these patients.

Impact of mutations in homologous recombination repair genes on treatment outcomes for metastatic castration resistant prostate cancer

INTRODUCTION

A significant proportion of patients with metastatic castration-resistant prostate cancer (mCRPC) harbor mutations in homologous recombination (HR) repair genes, with some of these mutations associating with increased tumor susceptibility to poly(ADP-ribose) polymerase (PARP) inhibitors and platinum-based chemotherapy. While mutations in some HR repair genes (e.g., BRCA1/2) have been associated with a more aggressive clinical course, prior studies correlating HR mutational status with treatment response to androgen receptor (AR) signaling inhibitors (ARSIs) or taxane-based chemotherapy have yielded conflicting results.

METHODS

We conducted a single-center retrospective analysis to assess clinical outcomes to conventional, regulatory-approved therapies in mCRPC patients with somatic (monoallelic and biallelic) and/or germline HR repair mutations compared to patients without alterations as determined by clinical-grade next-generation sequencing assays. The primary endpoint was PSA30/PSA50 response, defined as ≥30%/≥50% prostate-specific antigen (PSA) reduction from baseline. Secondary endpoints of PSA progression-free survival (pPFS) and clinical/radiographic progression-free survival (crPFS) were estimated using Kaplan-Meier methods.

RESULTS

A total of 90 consecutively selected patients were included in this analysis, of which 33 (37%) were identified to have HR repair gene mutations. Age, race, Gleason score, prior surgery, and receipt of prior radiation therapy were comparable between carriers and non-carriers. There was no evidence that PSA30/PSA50 differed by HR gene mutational status. Median pPFS and crPFS ranged 3-14 months across treatment modalities, but there was no evidence either differed by HR gene mutational status (all p>0.05). There was also no difference in outcomes between those with BRCA2 or PALB2 mutations (n = 17) compared to those without HR repair mutations.

CONCLUSION

HR gene mutational status was associated with comparable clinical outcomes following treatment with ARSIs or taxane-based chemotherapy. Additional prospective studies are needed to confirm these findings.

Potential biomarkers and risk assessment models to enhance the tumor-node-metastasis (TNM) staging classification of urologic cancers

INTRODUCTION

The anatomic-based TNM classification is considered the benchmark in cancer staging and has been regularly updated since its inception. In the current era of precision medicine, the added intention for future TNM modifications is to heighten its impact in the more 'personalized' level of cancer care. In urologic cancers, this goal may be achieved by incorporating 'non-anatomic' factors into TNM, such as biomarkers (e.g. gene alterations, molecular subtypes, genomic classifiers) and risk assessment models (e.g. nomogram, look-up table), while maintaining the anatomic extent as the foundation of staging. These different prognosticators can be combined and integrated, may serve as substratifiers for T, N, or M categories, and perhaps, incorporated as elements in TNM stage groupings to enhance their prognostic capability in urologic cancers.

AREAS COVERED

This review highlights candidate biomarkers and risk assessment models that can be explored to potentially improve TNM prognostication of bladder, prostate, kidney, and testicular cancers.

EXPERT OPINION

Recent advances in molecular analysis have increased the understanding of the genomic, transcriptomic, and epigenetic features for biomarker use in prognostication of urologic cancers, which together with the available risk assessment models, may complement and overcome the limitations of the traditional TNM staging.

Incorporating Prognostic Biomarkers into Risk Assessment Models and TNM Staging for Prostate Cancer

In current practice, prostate cancer staging alone is not sufficient to adequately assess the patient's prognosis and plan the management strategies. Multiple clinicopathological parameters and risk tools for prostate cancer have been developed over the past decades to better characterize the disease and provide an enhanced assessment of prognosis. Herein, we review novel prognostic biomarkers and their integration into risk assessment models for prostate cancer focusing on their capability to help avoid unnecessary imaging studies, biopsies and diagnosis of low risk prostate cancers, to help in the decision-making process between active surveillance and treatment intervention, and to predict recurrence after radical prostatectomy. There is an imperative need of reliable biomarkers to stratify prostate cancer patients that may benefit from different management approaches. The integration of biomarkers panel with risk assessment models appears to improve prostate cancer diagnosis and management. However, integration of novel genomic biomarkers in future prognostic models requires further validation in their clinical efficacy, standardization, and cost-effectiveness in routine application.

Genomic and Clinicopathologic Characterization of ATM-deficient Prostate Cancer

PURPOSE

The ATM (ataxia telangiectasia mutated) gene is mutated in a subset of prostate cancers, and ATM mutation may confer specific therapeutic vulnerabilities, although ATM-deficient prostate cancers have not been well-characterized.

EXPERIMENTAL DESIGN

We genetically validated a clinical grade IHC assay to detect ATM protein loss and examined the frequency of ATM loss among tumors with pathogenic germline ATM mutations and genetically unselected primary prostate carcinomas using tissue microarrays (TMAs). Immunostaining results were correlated with targeted somatic genomic sequencing and clinical outcomes.

RESULTS

ATM protein loss was found in 13% (7/52) of primary Gleason pattern 5 cancers with available sequencing data and was 100% sensitive for biallelic ATM inactivation. In a separate cohort with pathogenic germline ATM mutations, 74% (14/19) had ATM protein loss of which 70% (7/10) of evaluable cases had genomic evidence of biallelic inactivation, compared with zero of four of cases with intact ATM expression. By TMA screening, ATM loss was identified in 3% (25/831) of evaluable primary tumors, more commonly in grade group 5 (17/181; 9%) compared with all other grades (8/650; 1%; P < 0.0001). Of those with available sequencing, 80% (4/5) with homogeneous ATM protein loss and 50% (6/12) with heterogeneous ATM protein loss had detectable pathogenic ATM alterations. In surgically treated patients, ATM loss was not significantly associated with clinical outcomes in random-effects Cox models after adjusting for clinicopathologic variables.

CONCLUSIONS

ATM loss is enriched among high-grade prostate cancers. Optimal evaluation of ATM status requires both genomic and IHC studies and will guide development of molecularly targeted therapies.

BRCA Mutations in Prostate Cancer: Prognostic and Predictive Implications

Despite chemotherapy and novel androgen-receptor signalling inhibitors (ARSi) have been approved during the last decades, metastatic castration-resistant prostate cancer (mCRPC) remains a lethal disease with poor clinical outcomes. Several studies found that germline or acquired DNA damage repair (DDR) defects affect a high percentage of mCRPC patients. Among DDR defects, BRCA mutations show relevant clinical implications. BRCA mutations are associated with adverse clinical features in primary tumors and with poor outcomes in patients with mCRPC. In addition, BRCA mutations predict good response to poly-ADP ribose polymerase (PARP) inhibitors, such as olaparib, rucaparib, and niraparib. However, concerns still remain on the role of extensive mutational testing in prostate cancer patients, given the implications for patients and for their progeny. The present comprehensive review attempts to provide an overview of BRCA mutations in prostate cancer, focusing on their prognostic and predictive roles.

Genetic testing for the clinician in prostate cancer

INTRODUCTION

Prostate cancer (PCa) is one of the most common cancers worldwide and a leading cause of cancer-related mortality. Although the diagnosis and treatment of prostate cancer has improved substantially in recent years, new molecular biomarkers are needed to further prolong survival and improve the quality of life in these patients.

AREAS COVERED

This review analyzes the current evidence for prognostic and predictive molecular biomarkers that can be applied across different clinical scenarios, ranging from localized disease to metastatic castration-resistant PCa, with a particular emphasis on the biomarkers likely to become available in routine clinical practice in the near future.

EXPERT OPINION

There is a growing need for molecular testing to identify the most indolent types of prostate cancer to help optimize treatment strategies and spare treatment in these patients when possible. Current trends in the treatment of prostate cancer underscore the unmet clinical need for biomarkers to improve decision-making in a challenging clinical setting.

Impact of H19 Polymorphisms on Prostate Cancer Clinicopathologic Characteristics

Active surveillance is the preferred strategy for very low risk, low risk, and some favorable intermediate risk of prostate cancer. However, the current risk stratifications with initial prostate-specific antigen (iPSA) levels and Gleason scores at biopsy can underestimate the true oncologic threat. More precise predictors are required to avoid the overtreatment of prostate cancer. H19 single-nucleotide polymorphisms (SNPs) have been found to play crucial roles in numerous malignancies, but not yet in prostate cancer. This study assessed the clinicopathologic effects of H19 SNPs on prostate cancer to identify potential active surveillance candidates. A total of 579 patients with prostate cancer who underwent robot-assisted radical prostatectomy between 2012 and 2017 were recruited. The patients were grouped by iPSA levels, and five H19 SNPs were evaluated. Our results show that patients with an iPSA level of ≤7 ng/mL had increased an likelihood of having Gleason score and group grade upgrades after radical prostatectomy compared with patients with an iPSA level of >7 ng/mL. Moreover, patients with loci polymorphisms in either rs3024270 or rs3741219 had a significantly higher risk of perineural invasion (rs3024270: Odds ratio (OR) 2.76, 95% confidence interval (CI) 1.30-5.87, p = 0.01; rs3741219: OR 2.30, 95% CI 1.17-4.54, p = 0.018). In conclusion, our results suggested that H19 SNPs play a role in the perineural invasion of prostate cancer.

Implementation of Germline Testing for Prostate Cancer: Philadelphia Prostate Cancer Consensus Conference 2019

PURPOSE

Germline testing (GT) is a central feature of prostate cancer (PCA) treatment, management, and hereditary cancer assessment. Critical needs include optimized multigene testing strategies that incorporate evolving genetic data, consistency in GT indications and management, and alternate genetic evaluation models that address the rising demand for genetic services.

METHODS

A multidisciplinary consensus conference that included experts, stakeholders, and national organization leaders was convened in response to current practice challenges and to develop a genetic implementation framework. Evidence review informed questions using the modified Delphi model. The final framework included criteria with strong (> 75%) agreement (Recommend) or moderate (50% to 74%) agreement (Consider).

RESULTS

Large germline panels and somatic testing were recommended for metastatic PCA. Reflex testing-initial testing of priority genes followed by expanded testing-was suggested for multiple scenarios. Metastatic disease or family history suggestive of hereditary PCA was recommended for GT. Additional family history and pathologic criteria garnered moderate consensus. Priority genes to test for metastatic disease treatment included BRCA2, BRCA1, and mismatch repair genes, with broader testing, such as ATM, for clinical trial eligibility. BRCA2 was recommended for active surveillance discussions. Screening starting at age 40 years or 10 years before the youngest PCA diagnosis in a family was recommended for BRCA2 carriers, with consideration in HOXB13, BRCA1, ATM, and mismatch repair carriers. Collaborative (point-of-care) evaluation models between health care and genetic providers was endorsed to address the genetic counseling shortage. The genetic evaluation framework included optimal pretest informed consent, post-test discussion, cascade testing, and technology-based approaches.

CONCLUSION

This multidisciplinary, consensus-driven PCA genetic implementation framework provides novel guidance to clinicians and patients tailored to the precision era. Multiple research, education, and policy needs remain of importance.

Prostate Cancer, Version 2.2019, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Prostate Cancer include recommendations regarding diagnosis, risk stratification and workup, treatment options for localized disease, and management of recurrent and advanced disease for clinicians who treat patients with prostate cancer. The portions of the guidelines included herein focus on the roles of germline and somatic genetic testing, risk stratification with nomograms and tumor multigene molecular testing, androgen deprivation therapy, secondary hormonal therapy, chemotherapy, and immunotherapy in patients with prostate cancer.

PARP inhibitors in castration-resistant prostate cancer

Somatic or germline mutations in genes regulating DNA damage repair have been noted in around 20% of patients with advanced prostate cancer. Poly-ADP-ribose polymerase (PARP) inhibitors have shown encouraging efficacy in prostate cancer patients with DNA repair mutations. Two PARP inhibitors, olaparib, and rucaparib have recently received FDA approval for treatment of patients with advanced castration-resistant prostate cancer (CRPC), while several trials with other PARP inhibitors are ongoing. Here, we briefly summarize the current data supporting the efficacy of PARP inhibitors in advanced CRPC.

Hereditary Predisposition to Prostate Cancer: From Genetics to Clinical Implications

Prostate cancer (PrCa) ranks among the top five cancers for both incidence and mortality worldwide. A significant proportion of PrCa susceptibility has been attributed to inherited predisposition, with 10-20% of cases expected to occur in a hereditary/familial context. Advances in DNA sequencing technologies have uncovered several moderate- to high-penetrance PrCa susceptibility genes, most of which have previously been related to known hereditary cancer syndromes, namely the hereditary breast and ovarian cancer (BRCA1, BRCA2, ATM, CHEK2, and PALB2) and Lynch syndrome (MLH1, MSH2, MSH6, and PMS2) genes. Additional candidate genes have also been suggested, but further evidence is needed to include them in routine genetic testing. Recommendations based on clinical features, family history, and ethnicity have been established for more cost-efficient genetic testing of patients and families who may be at an increased risk of developing PrCa. The identification of alterations in PrCa predisposing genes may help to inform screening strategies, as well as treatment options, in the metastatic setting. This review provides an overview of the genetic basis underlying hereditary predisposition to PrCa, the current genetic screening recommendations, and the implications for clinical management of the disease.

New Frontiers in Prostate Cancer Treatment: Are We Ready for Drug Combinations with Novel Agents?

Medical treatment for metastatic castration-resistant prostate cancer (mCRPC) patients has progressively been evolving from a nonspecific clinical approach to genomics-oriented therapies. The scientific community is in fact increasingly focusing on developing DNA damage repair (DDR) defect-driven novel molecules, both as single-agent therapy and in combined treatment strategies. Accordingly, research is under way into combined drug therapies targeting different pathways, e.g. androgen receptor signaling (ARS) and poly (adenosine diphosphate [ADP]-ribose) polymerase (PARP) enzymes, immune checkpoint (IC) and PARP, IC, and ARS, and prostate-specific membrane antigen (PSMA). In an attempt to formulate evolving treatment paradigms in mCRPC patients, here we selected clinical research into patients undergoing therapies with emerging molecules, with particular emphasis towards PARP-, IC-, and PSMA-inhibitors. In order to focus on those molecules and drug combinations most likely to be translated into routine clinical care in the near future, we selected only those clinical studies currently recruiting patients. A PubMed search focusing on the keywords “prostate cancer”, “metastatic castration-resistant prostate cancer”, “DDR pathways”, “ARS inhibitors”, “PARP inhibitors”, “IC inhibitors”, “PSMA-targeting agents”, and “drug combinations” was performed.

Metastatic Hormone-Sensitive Prostate Cancer (mHSPC): Advances and Treatment Strategies in the First-Line Setting

The treatment landscape of metastatic hormone-sensitive prostate cancer (mHSPC) has changed radically in recent years. Androgen deprivation therapy (ADT) alone was for decades the standard of care for treating mHSPC. This changed when studies showed that the addition of docetaxel chemotherapy or abiraterone acetate to ADT significantly increases overall survival of patients with mHSPC, followed by more recent evidence showing the efficacy of androgen receptor antagonists, such as enzalutamide and apalutamide, in this setting. While this rapid therapeutic evolution is welcome, it presents clinicians with a crucial challenge: the choice of treatment selection and sequencing. In the first-line setting there are no comparative data currently available to guide treatment choice between the different available regimens, and no prospective data to guide clinical decision after progression. Decisions on treatment will now need to be personalised based on indirect comparison of the available efficacy data from multiple phase 3 studies, together with considerations of disease volume, comorbidities, treatment aims, toxicity profile and cost reimbursement within the healthcare setting. Here, we provide an overview of the clinical trial data to date and propose some biological and clinical insights which may be helpful in making decisions on treatment selection and sequencing.

Clinical Applications of Molecular Biomarkers in Prostate Cancer

There is clinically relevant molecular heterogeneity in prostate cancer (PCa), but this biological diversity has had only a minimal impact on clinical practice. Treatment outcomes in patients with localised PCa are often highly variable, even among patients stratified to the same risk group or disease state based on standard clinical and pathological parameters. In recent years, the development of gene panels has provided valuable data on the differential expression of genes in patients with PCa. Nevertheless, there is an urgent need to identify and validate prognostic and predictive biomarkers that can be applied across clinical scenarios, ranging from localised disease to metastatic castration-resistant PCa. The availability of such tools would allow for precision medicine to finally reach PCa patients. In this review, we evaluate current data on molecular biomarkers for PCa, with an emphasis on the biomarkers and gene panels with the most robust evidence to support their application in routine clinical practice.

Pharmacotherapeutic strategies for castrate-resistant prostate cancer

INTRODUCTION

Metastatic castration-resistant prostate cancer (CRPC) is a potentially symptomatic disease with an eventual lethal outcome. Novel pharmaceutical agents are continuously studied with encouraging results in CRPC.

AREAS COVERED

In this perspective, the authors present established and promising pharmacotherapeutic strategies for the management of CRPC; both with and without metastases. Apart from the different treatment strategies, the authors present the relevant sequence of treatment through disease progression.

EXPERT OPINION

Usually, docetaxel should be considered the first line treatment in mCRPC. Abiraterone acetate (AA) plus prednisone or enzalutamide (ENZ) could be alternative treatments in chemotherapy naïve patients. Sipuleucel-T has been approved for the treatment of asymptomatic or minimally symptomatic mCRPC. Ra-223 has been approved for patients with mCRPC with symptomatic bone metastases (not visceral metastases). Cabazitaxel has been approved as the second line treatment to docetaxel in mCRPC. No differences in the overall survival has been observed between sequences starting with docetaxel versus AA/ENZ. Between AA-to-ENZ and ENZ-to-AA sequence, the AA-to-ENZ sequence appeared to be more favorable than the ENZ-to-AA regarding progression-free survival but not overall survival. Carbazitaxel seemed to retain its activity regardless of the treatment sequence. Of note, ENZ and apalutamide have been approved in non-metastatic CRPC.

Olaparib for Metastatic Castration-Resistant Prostate Cancer

BACKGROUND

Multiple loss-of-function alterations in genes that are involved in DNA repair, including homologous recombination repair, are associated with response to poly(adenosine diphosphate-ribose) polymerase (PARP) inhibition in patients with prostate and other cancers.

METHODS

We conducted a randomized, open-label, phase 3 trial evaluating the PARP inhibitor olaparib in men with metastatic castration-resistant prostate cancer who had disease progression while receiving a new hormonal agent (e.g., enzalutamide or abiraterone). All the men had a qualifying alteration in prespecified genes with a direct or indirect role in homologous recombination repair. Cohort A (245 patients) had at least one alteration in BRCA1, BRCA2, or ATM; cohort B (142 patients) had alterations in any of 12 other prespecified genes, prospectively and centrally determined from tumor tissue. Patients were randomly assigned (in a 2:1 ratio) to receive olaparib or the physician's choice of enzalutamide or abiraterone (control). The primary end point was imaging-based progression-free survival in cohort A according to blinded independent central review.

RESULTS

In cohort A, imaging-based progression-free survival was significantly longer in the olaparib group than in the control group (median, 7.4 months vs. 3.6 months; hazard ratio for progression or death, 0.34; 95% confidence interval, 0.25 to 0.47; P<0.001); a significant benefit was also observed with respect to the confirmed objective response rate and the time to pain progression. The median overall survival in cohort A was 18.5 months in the olaparib group and 15.1 months in the control group; 81% of the patients in the control group who had progression crossed over to receive olaparib. A significant benefit for olaparib was also seen for imaging-based progression-free survival in the overall population (cohorts A and B). Anemia and nausea were the main toxic effects in patients who received olaparib.

CONCLUSIONS

In men with metastatic castration-resistant prostate cancer who had disease progression while receiving enzalutamide or abiraterone and who had alterations in genes with a role in homologous recombination repair, olaparib was associated with longer progression-free survival and better measures of response and patient-reported end points than either enzalutamide or abiraterone. (Funded by AstraZeneca and Merck Sharp & Dohme; PROfound ClinicalTrials.gov number, NCT02987543.).

Latest progress in molecular biology and treatment in genitourinary tumours

The management of genitourinary cancer, including bladder, prostate, renal and testicular cancer, has evolved dramatically in recent years due to a better understanding of tumour genetic mutations, alterations in molecular pathways, and to the development of new kinds of drugs such as targeted therapies and immunotherapies. In the field of immunotherapy, new drugs focused on stimulating, enhancing and modulating the immune system to detect and destroy cancer, have been recently discovered. Research in oncology moves quickly and new data of great relevance for clinical practice are communicated every year. For this reason, a group of experts, focused exclusively on the treatment of genitourinary tumours and who get together every year in the BestGU conference to assess the latest progress in this field have summarized the most important advances in a single review, along with a critical assessment of whether these results should alter daily clinical practice.

Rare germline genetic variants and risk of aggressive prostate cancer

Few genetic risk factors have been demonstrated to be specifically associated with aggressive prostate cancer (PrCa). Here, we report a case-case study of PrCa comparing the prevalence of germline pathogenic/likely pathogenic (P/LP) genetic variants in 787 men with aggressive disease and 769 with nonaggressive disease. Overall, we observed P/LP variants in 11.4% of men with aggressive PrCa and 9.8% of men with nonaggressive PrCa (two-tailed Fisher's exact tests, P = .28). The proportion of BRCA2 and ATM P/LP variant carriers in men with aggressive PrCa exceeded that observed in men with nonaggressive PrCa; 18/787 carriers (2.3%) and 4/769 carriers (0.5%), P = .004, and 14/787 carriers (0.02%) and 5/769 carriers (0.01%), P = .06, respectively. Our findings contribute to the extensive international effort to interpret the genetic variation identified in genes included on gene-panel tests, for which there is currently an insufficient evidence-base for clinical translation in the context of PrCa risk.

Therapeutic targeting of the DNA damage response in prostate cancer

PURPOSE OF REVIEW

The present article highlights the most common DNA repair gene mutations, using specific examples of individual genes or gene classes, and reviews the epidemiology and treatment implications for each one [with particular emphasis on poly-ADP-ribose polymerase (PARP) inhibition and PD-1 blockade].

RECENT FINDINGS

Genetic and genomic testing have an increasingly important role in the oncology clinic. For patients with prostate cancer, germline genetic testing is now recommended for all men with high-risk and metastatic disease, and somatic multigene tumor testing is recommended for men with metastatic castration-resistant disease. The most common mutations that are present in men with advanced prostate cancer are in genes coordinating DNA repair and the DNA damage response.

SUMMARY

Although much of what is discussed currently remains investigational, it is clear that genomically-targeted treatments will become increasingly important for patients with prostate cancer in the near future and beyond.

High prevalence of DNA damage repair gene defects and TP53 alterations in men with treatment-naïve metastatic prostate cancer -Results from a prospective pilot study using a 37 gene panel

BACKGROUND

Defects in DNA damage repair genes characterize a subset of men with prostate cancer and provide an attractive opportunity for precision oncology approaches. The prevalence of such perturbations in newly diagnosed, treatment-naïve patients with a high risk for lethal disease outcome, however, has not been sufficiently explored.

PATIENTS AND METHODS

Prostate cancer specimens from 67 men with newly diagnosed early onset, localized high-risk/locally advanced or metastatic prostate cancer were included in this prospective pilot study. Tumor samples, including 30 prostate biopsies, were analyzed by targeted next generation sequencing using a formalin-fixed, paraffin-embedded tissue-optimized 37 DNA damage repair and checkpoint gene panel.

RESULTS

The drop-out rate due to an insufficient quantity of DNA was 4.5% (3 of 67 patients). In the remaining 64 patients, the rate of pathogenic DNA damage repair gene mutations was 26.6%. The highest rate of pathogenic DNA damage repair and checkpoint gene mutations was found in men with treatment-naïve metastatic prostate cancer (38.9%). In addition, a high number of likely pathogenic mutations and gene deletions were detected. Altogether, one or more pathogenic mutation, likely pathogenic mutation or gene deletion affected 43 of 64 patients (67.2%) including 29 of 36 patients (80.6%) with treatment-naïve metastatic prostate cancer. Men with metastatic prostate cancer showed a high prevalence of alterations in TP53 (36.1%).

CONCLUSIONS

This pilot study demonstrates the feasibility, performance and clinical relevance of somatic targeted next generation sequencing using a unique 37 DNA damage repair and checkpoint gene panel under routine conditions. Our results indicate that this approach can detect actionable DNA repair gene alterations, uncommon mutations as well as mutations associated with therapy resistance in a high number of patients, in particular patients with treatment-naïve metastatic prostate cancer.