Localized prostate cancers are genetically variable and frequently multifocal, comprising spatially distinct regions with multiple independently-evolving clones. To date there is no understanding of ...whether this variability can influence management decisions for patients with prostate tumors. Here, we present a single case from a clinical trial of neoadjuvant intense androgen deprivation therapy. A patient was diagnosed with a large semi-contiguous tumor by imaging, histologically composed of a large Gleason score 9 tumor with an adjacent Gleason score 7 nodule. DNA sequencing demonstrates these are two independent tumors, as only the Gleason 9 tumor harbors single-copy losses of PTEN and TP53. The PTEN/TP53-deficient tumor demonstrates treatment resistance, selecting for subclones with mutations to the remaining copies of PTEN and TP53, while the Gleason 7 PTEN-intact tumor is almost entirely ablated. These findings indicate that spatiogenetic variability is a major confounder for personalized treatment of patients with prostate cancer.
BackgroundClinical trials have shown the ability of therapeutic vaccines to generate immune responses to tumor-associated antigens (TAAs). What is relatively less known is if this translates into ...immune-cell (IC) infiltration into the tumor microenvironment. This study examined whether neoadjuvant prostate-specific antigen (PSA)-targeted vaccination with PROSTVAC could induce T-cell immunity, particularly at the tumor site.MethodsAn open-label, phase II study of neoadjuvant PROSTVAC vaccine enrolled 27 patients with localized prostate cancer awaiting radical prostatectomy (RP). We evaluated increases in CD4 and CD8 T-cell infiltrates (RP tissue vs baseline biopsies) using a six-color multiplex immunofluorescence Opal method. Antigen-specific responses were assessed by intracellular cytokine staining after in vitro stimulation of peripheral blood mononuclear cells with overlapping 15-mer peptide pools encoding the TAAs PSA, brachyury and MUC-1.ResultsOf 27 vaccinated patients, 26 had matched prevaccination (biopsy) and postvaccination (RP) prostate samples available for non-compartmentalized analysis (NCA) and compartmentalized analysis (CA). Tumor CD4 T-cell infiltrates were significantly increased in postvaccination RP specimens compared with baseline biopsies by NCA (median 176/mm² vs 152/mm²; IQR 136–317/mm² vs 69–284/mm²; p=0.0249; median ratio 1.20; IQR 0.64–2.25). By CA, an increase in both CD4 T-cell infiltrates at the tumor infiltrative margin (median 198/mm² vs 151/mm²; IQR 123–500/mm² vs 85–256/mm²; p=0.042; median ratio 1.44; IQR 0.59–4.17) and in CD8 T-cell infiltrates at the tumor core (median 140/mm² vs 105/mm²; IQR 91–175/mm² vs 83–163/mm²; p=0.036; median ratio 1.25; IQR 0.88–2.09) were noted in postvaccination RP specimens compared with baseline biopsies. A total of 13/25 patients (52%) developed peripheral T-cell responses to any of the three tested TAAs (non-neoantigens); five of these had responses to more than one antigen of the three evaluated.ConclusionNeoadjuvant PROSTVAC can induce both tumor immune response and peripheral immune response.Trial registration numberNCT02153918.
Abstract
Background: In this study we report the effects of neoadjuvant enzalutamide (enza) plus androgen deprivation therapy (ADT) in the prostatectomy specimens of patients receiving this therapy, ...and the immunoprofile of the tumors. Prostate cancer is the most common cancer in men, affecting 1 out of 9 men in the US. Treatment for newly diagnosed, non-metastatic, high-risk disease includes surgery or radiation in combination with ADT. Enza, an androgen receptor antagonist, is FDA approved for non-metastatic and metastatic castrate-resistant prostate cancer. Studies have shown intensive androgen receptor targeting for localized disease can lead to complete responses.
Design: Single institution study (NCT02430480) evaluating 6 months of neoadjuvant enza (160 mg daily) plus ADT in patients with high risk non-metastatic prostatic cancer. Twenty-two prostatectomy specimens were evaluated. Specimens were fixed in formalin and paraffin embedded following the protocol established for these specimens. Detailed morphological evaluation was performed and tumors compared with prior diagnostic biopsies. Correlation with prior multiparametric MRI (mpMRI) was done. Sections with tumor were obtained (4mm thickness) and stained for IHC for PTEN antibody (Cell signaling), AR (Abcam) and ERG (Abcam)
Results: Patients ranged in age from 43 to 73 years (med 61years). Prior biopsies included Gleason scores of 7(3+4,5 cases); 7(4+3, 3 cases), 8(4+4, 5 cases),9(4+5, 8 cases), 10(1 case). Grossly, the prostatectomy specimens appeared smaller in size. Reviewing prior mpMRI, it was noted that the median prostate volume decreased by 50.7% after 6 months of treatment. No tumor was identified in 2 cases; one with multiple Gleason grade 8 biopsies and the other one Gleason grade 9 in all prior biopsies. In all except 2 cases, the most striking histologic change was the tumor cells that often resembled fusiform histiocytes growing in discrete clusters or individual cells. Occasional small gland formation was present in some cases. Prominent basal cell hyperplasia was present as well as nodular stromal hyperplasia that in MRI mimic cancer. The amount of tumor present varied from bilateral involvement to 10% of one lobe. Most cases were stage pT2 and pT3. 20 cases were positive for AR, 3 had loss of PTEN and 5 had ERG expression (total 22 cases).
Conclusions: Enzalutamide is a potent antiandrogen with promising results in the neoadjuvant treatment of high-risk prostatic cancer. We report in this study the effect and morphologic changes that occur in the tumor as the result of this therapy. Recognition of these morphologic changes is important since the residual tumor may appear different than the prior diagnostic biopsies.
Citation Format: Maria J. Merino, Esra Dikoglu, Peter Pinto, Baris Turkbey, William Dahut, Guinevere Chun, Ravi A. Madan, Fatima Karzai. The morphologic effects of treatment with neoadjuvant enzalutamide and androgen deprivation therapy in high risk prostatic cancer: What the pathologist needs to know abstract. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 618.
Patients diagnosed with high risk localized prostate cancer have variable outcomes following surgery. Trials of intense neoadjuvant androgen deprivation therapy (NADT) have shown lower rates of ...recurrence among patients with minimal residual disease after treatment. The molecular features that distinguish exceptional responders from poor responders are not known.
To identify genomic and histologic features associated with treatment resistance at baseline.
Targeted biopsies were obtained from 37 men with intermediate- to high-risk prostate cancer before receiving 6 mo of ADT plus enzalutamide. Biopsy tissues were used for whole-exome sequencing and immunohistochemistry (IHC).
We assessed the relationship of molecular features with final pathologic response using a cutpoint of 0.05 cm3 for residual cancer burden to compare exceptional responders to incomplete and nonresponders. We assessed intratumoral heterogeneity at the tissue and genomic level, and compared the volume of residual disease to the Shannon diversity index for each tumor. We generated multivariate models of resistance based on three molecular features and one histologic feature, with and without multiparametric magnetic resonance imaging estimates of baseline tumor volume.
Loss of chromosome 10q (containing PTEN) and alterations to TP53 were predictive of poor response, as were the expression of nuclear ERG on IHC and the presence of intraductal carcinoma of the prostate. Patients with incompletely and nonresponding tumors harbored greater tumor diversity as estimated via phylogenetic tree reconstruction from DNA sequencing and analysis of IHC staining. Our four-factor binary model (area under the receiver operating characteristic curve AUC 0.89) to predict poor response correlated with greater diversity in our cohort and a validation cohort of 57 Gleason score 8–10 prostate cancers from The Cancer Genome Atlas. When baseline tumor volume was added to the model, it distinguished poor response to NADT with an AUC of 0.98. Prospective use of this model requires further retrospective validation with biopsies from additional trials.
A subset of prostate cancers exhibit greater histologic and genomic diversity at the time of diagnosis, and these localized tumors have greater fitness to resist therapy.
Some prostate cancer tumors do not respond well to a hormonal treatment called androgen deprivation therapy (ADT). We used tumor volume and four other parameters to develop a model to identify tumors that will not respond well to ADT. Treatments other than ADT should be considered for these patients.
A subset of patients present with high-risk localized prostate cancer that exhibits greater histologic and genomic diversity. These patients are less likely to respond to intense neoadjuvant androgen deprivation therapy.
For high-risk prostate cancer, standard treatment options include radical prostatectomy (RP) or radiotherapy plus androgen deprivation therapy (ADT). Despite definitive therapy, many patients will ...have disease recurrence. Imaging has the potential to better define characteristics of response and resistance. In this study, we evaluated prostate multiparametric MRI (mpMRI) before and after neoadjuvant enzalutamide plus ADT.
Men with localized intermediate- or high-risk prostate cancer underwent a baseline mpMRI and mpMRI-targeted biopsy followed by a second mpMRI after 6 months of enzalutamide and ADT prior to RP. Specimens were sectioned in the same plane as mpMRI using patient-specific 3D-printed molds to permit mpMRI-targeted biopsies to be compared with the same lesion from the RP. Specimens were analyzed for imaging and histologic correlates of response.
Of 39 patients enrolled, 36 completed imaging and RP. Most patients (92%) had high-risk disease. Fifty-eight lesions were detected on baseline mpMRI, of which 40 (69%) remained measurable at 6-month follow-up imaging. Fifty-five of 59 lesions (93%) demonstrated >50% volume reduction on posttreatment mpMRI. Three of 59 lesions (5%) demonstrated growth in size at follow-up imaging, with two lesions increasing more than 3-fold in volume. On whole-mount pathology, 15 patients demonstrated minimal residual disease (MRD) of <0.05 cc or pathologic complete response. Low initial mpMRI relative tumor burden was most predictive of MRD on final pathology.
Low relative lesion volume at baseline mpMRI was predictive of pathologic response. A subset of patients had limited response. Selection of patients based on these metrics may improve outcomes in high-risk disease.
Abstract only
368
Background: PCa is driven by androgen receptor (AR) signaling and neoadjuvant therapy with AR inhibitors offer an opportunity to improve cure rates in high-risk PCa particularly ...with utilization of multiparametric MRI (mpMRI). A loss of AR-regulated lineage characteristics and genomic loss of tumor suppressors RB1 and TP53 or mutations in DNA damage repair (DDR) genes can represent aggressive prostate variants. We conducted a feasibility study using mpMRI to evaluate tumor responses and resistance in newly diagnosed, high-risk PCa (NCT02430480). Methods: Pts were treated with androgen deprivation therapy (ADT) + enzalutamide (enza) 160 mg daily for 6 months (mos). Pts underwent 2 mpMRIs: baseline and post 6 mos treatment (trt). Post-trt mpMRI was followed by radical prostatectomy (RP). Primary endpoint: feasibility of mpMRI for localization and detection of PCa before and after ADT + enza. Results: 39 pts were enrolled on-study with 36 pts completing 6 mos trt and undergoing RP. Of 39 pts, 3 had disease progression. Conclusions: Neoadjuvant intense testosterone lowering therapy shows activity in PCa but a subset of pts not respond to AR-targeted therapies through lineage plasticity enabled by characteristic loss of RB1 and TP53 or due to genetic alterations. Identification of this high-risk patient population, along with development of treatment options, needs further investigation. Clinical trial information: NCT02430480. Table: see text
Abstract
Background: Genetic alterations in lethal, metastatic prostate cancer include the loss of PTEN, translocation of the TMPRSS2 and ERG genes, upregulation of the androgen receptor (AR), and ...disruption of the DNA homologous repair pathway driven by mutations to BRCA1, BRCA2, and ATM. Many of these mutations can be observed while the cancer is still localized in the prostate. Here, we seek to identify genetic features indicative of therapeutic response and novel drivers of cancer progression to inform clinical practice.
Methods: Using tissue from 33 patients in an intense neoadjuvant anti-androgen clinical trial at the NCI (NCT02430480), we examined genetic features that would predict exceptional or poor response to anti-androgen enzalutamide therapy. Each patient on trial presented with multiple tumor foci, allowing us to investigate the intratumoral heterogeneity across foci within individual patients, as well as investigating the tumor profiles across multiple patients. Several patients exhibited exceptional response with residual tumor burdens less than 0.5cc, while others had substantial treatment-resistant cancers. We developed a panel of 12 immunohistopathological stains and used this panel to guide laser capture microdissection on pre-treatment biopsies and spatially matched post-treatment radical prostatectomy specimens to isolate ultrapure tumor foci from each patient. DNA from these foci was used for whole exome sequencing, as somatic copy number alterations and mutations also confirm their evolutionary relationship. This enabled us to classify baseline specimens as responder or nonresponder, while examining variations in genetic features between the two cohorts.
Results: To date, focal PTEN loss was observed in all nonresponders, while focal ERG staining was absent in 100% of responders and present in 60% of nonresponders. Synaptophysin positivity was rare at baseline but predicted resistance to treatment with 100% sensitivity. Intriguingly, baseline copy number profiles highlight a 6q deletion in 100% of exceptional responders, but not in the non-responders. Together, these data suggest an immunostain panel to assess oncogene and tumor suppressor alterations can predict response to anti-androgen therapy, while also suggesting a novel role of 6q in resistance to anti-androgen hormone therapy. Current studies are examining the role of 6q in response to anti-androgen therapies, which remains an area of active interest in our laboratory.
Conclusions: These findings demonstrate the feasibility in identifying intratumoral heterogeneity based on prostate biomarker status both in pre-treatment and post-treatment specimens. Using these data, comprehensive molecular analysis of prostate cancer at diagnosis may better-enable physicians to predict response to anti-androgen therapy and provide tailored treatment based on gene expression status.
Citation Format: Scott Wilkinson, Huihui Ye, Nicole Carrabba, Rayann Atway, Shana Y. Trostel, Thomas Hennigan, Ross Lake, Stephanie Harmon, Guinevere Chun, Baris Turkbey, Peter A. Pinto, Peter L. Choyke, Fatima Karzai, David J. VanderWeele, Kathleen Kelly, William L. Dahut, Adam G. Sowalsky. Combining genetic and histopathologic features to predict response to anti-androgen therapy in aggressive prostate cancer abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2510.
Abstract only
e16536
Background: Docetaxel has become a standard of care for mCSPC. Enzalutamide and abiraterone have been proven to improve survival in metastatic castration-resistant prostate ...cancer (mCRPC) patients. Little is known about patients who have been treated with docetaxel for mCSPC and subsequent therapeutic responses. This retrospective analysis is to evaluate the response duration of abiraterone and enzalutamide in patients who previously received docetaxel for mCSPC but developed mCRPC within 12 months. Methods: Clinical Trial NCT02649855 enrolled patients with newly diagnosed mCSPC who were treated with standard androgen deprivation therapy (ADT) and docetaxel (75 mg/m2 every 3 weeks for 6 cycles) sequenced with immunotherapy (PROSTVAC) from February 2016 to present. Patients who had progression (based on consecutive PSA rises or imaging) within 1 year of completing docetaxel and went on to subsequent abiraterone/enzalutamide were evaluated. (Note these are different PSA progression criteria than used in CHAARTED, Sweeney, NEJM, 2015). A PCR-based NGS panel (OncoMine Comprehensive Assay v3) will evaluate available tissue from these patients. Results: Of the 46 patients evaluated regardless of immunotherapy sequence, 15 (33%) went on subsequent therapy after progression on docetaxel for mCSPC, with 12 patients starting abiraterone/enzalutamide (7 with high volume disease and 5 with low volume disease). The median age was 62 (41-83) years. 6/12 patients (50%) initiated enzalutamide and 6/12 patients (50%) initiated abiraterone. The median duration of treatment for both was 7.43 (1.53 – 16.0) months, the median time to prostate-specific antigen (PSA) progression was 2 (0 – 11) months; the median duration of PSA decline was 2 months in patients with both high and low volume disease. Of note, 3/12 (25%) of patients did not have PSA response, all of them had high volume disease. Conclusions: These data from a small cohort suggest that patients who have progression within 12 months of completing docetaxel for mCSPC have limited subsequent benefit from enzalutamide or abiraterone. Additional studies are required to determine optimal timing and treatment sequence for patients with mCSPC who rapidly develop mCRPC. Clinical trial information: NCT02649855.
Abstract only
61
Background: AR directed therapies are standard of care for metastatic prostate cancer, and their use for high-risk localized disease may improve survival. Previous trials showed that ...suppression of AR activity resulting in greater pathologic responses improved survival rates. However, the underlying biology and molecular features of exceptionally responding tumors remain unknown. Methods: Men with locally advanced prostate cancer (median Gleason score 8, median PSA 9.58 ng/dl) received mpMRI and MRI/US-fusion targeted biopsies at baseline. Patients received 6 months of ADT plus enzalutamide, then received a second mpMRI, and underwent radical prostatectomy. RP specimens were whole mounted in the same plane as MRI. The location of each tumor on biopsy was mapped to prostatectomy specimens using pathologic and imaging hallmarks. FFPE sections of baseline and post-treatment tumor were stained, laser capture microdissected, and analyzed using whole exome sequencing. Amongst nonresponding patients (residual tumor burden > 0.05 cc) comparison of pre- and post-treatment tumor specimens identified evolutionary phylogenies over space and time representing intrinsic or clonal selection of pre-existing cells. Amongst responding patients, clonal extinction was confirmed by sequencing and immunostaining of surgical specimens. Results: Gleason score at baseline did not differentiate responding and nonresponding patients. Focal ERG staining in biopsies was absent in 100% of responders and present in 60% of responders. Intraductal carcinoma architecture was also absent in all responding tumors. Focal PTEN loss was observed in all nonresponders at baseline. Responding tumor foci were enriched for deletion of chromosome 6q. Comparison of baseline mpMRI sequences indicated a trend towards lower variance on dynamic contract enhanced (DCE) MR and lower local texture heterogeneity metrics in responding lesions. Conclusions: Response to neoadjuvant intense ADT correlates with distinctive pathologic, molecular, and imaging features that can be observed prior to treatment. Selection of patients based on these parameters may improve overall responses to treatment in subsequent clinical trials. Clinical trial information: NCT02430480.
Abstract only
63
Background: Neoadjuvant therapy with novel androgen receptor inhibitors, like enza, offer an opportunity to improve cure rates in men with high risk PC but also emphasizes the need ...for improved imaging techniques and genomic studies to evaluate treatment (trt) responses. We conducted a feasibility study using mpMRI to evaluate tumor responses and resistance in newly diagnosed, high-risk PC. Methods: Patients (pts) were treated with androgen deprivation therapy (ADT) + enza 160 mg po qdaily for 6 months (mos). Pts underwent 2 mpMRI: baseline and post 6 mos of therapy. Post-trt mpMRI was followed by radical prostatectomy (RP). Primary endpoint was feasibility of mpMRI for localization and detection of PC before and after therapy with ADT + enza. Results: 31 out of 33 pts completed 6 mos of therapy and underwent RP. Median on-study PSA was 9.58 (1.18-984.72 ng/dL). Median PSA post 6 mos of ADT + enza was <0.02 (0.02-0.35 ng/mL). No pt was taken off-trt for adverse events. Median residual cancer burden (RCB) defined as volume of tumor corrected by tumor cellularity was 0.1584 (0.0001-12.32 cc). Using RCB of <0.05 cc, 12 patients had minimal residual disease of which 4 pts were pathologic complete responses. Post-trt mpMRI volume correlated with final pathology in all cases. Conclusions: Neoadjuvant enza + ADT is tolerable and shows activity in a newly-diagnosed, high-risk population. mpMRI can be utilized to assess responses to trt. Analysis of genomic characteristics and resistance mechanisms is on-going. Clinical trial information: NCT02430480.
PDF
