Prostate Cancer Relapse Research Articles

The Indication of Antiandrogen Therapy and Timing of Radiotherapy in Case of Prostate Cancer Relapse – a Literature Discussion on Shipley et al. 2017

The authors Shipley et al. (1917) report on the results of a phase-3 RTOG-Study, which demonstrates, that a 24-months anti androgen therapy with daily bicalutamide in addition to salvage radiotherapy prolongs in high risk patients (high PSA-values, i.e. >0, 7 ng/ml) the long-term survival and reduces the rate of metastases. However the RTOG-study does not report on relevant other urogenital, hepatotoxic or cardiac side effects. An evaluation of the data of the Martini-clinic in Hamburg yielded that a radical prostatectomy leads in 9% to an incontinence (>1 pads/24 hours), in 13% in case of a postoperative radiotherapy. After surgery alone the potency was maintained in 58% compared to only 40% (p=0,001) after trimodal therapy. The question is to debate, if the indication for an immediate postoperative radiotherapy should be chosen or, still better, a primary radiotherapy should be preferred in patients with median or high risk.

Lung uptake of fluorine-18 fluoroethyl-choline PET-CT in patients with prostate cancer.

Metastatic spreading to the lungs is a negative prognostic factor in patients with prostate cancer (PC). Aim of our study was to assess the prevalence of lung PC metastases in patients with fluorine-18 fluoroethyl-choline (F-18-FECh) PET-CT positive lung lesions and the role of Gleason Score (GS) and common biochemical markers in predicting metastatic spreading to the lungs. We retrospectively evaluated the scans of 1283 patients ongoing (F-18-FECh) PET-CT for PC between May 2010 and July 2014. Patients with lung lesion with F-18-FECh uptake were included. Data concerning GS at diagnosis, "trigger" prostate-specific antigen (PSAtr), PSA doubling time (PSAdt), PSA velocity (PSAvel) and ongoing androgen deprivation therapy were collected. PET-CT findings were confirmed by histology or follow-up (FU) and classified as follows: inflammation, primary lung cancer or metastases from tumor other than PC, and lung metastases from PC. Twenty-two patients with F-18-FECh positive lung lesion and available histology or FU were identified. PSAdt was significantly (P=0.029) shorter in patients with lung metastases from PC (median PSAdt 1.7 months, interquartile range [IQR] 1.5-4.1 months) than in patients without lung PC relapse (median PSAdt 6.7 months, IQR 3.9-7.8); PSAvel was significantly (P=0.019) higher in patients with lung metastases from PC (median PSAvel 3.2 ng/mL/month, IQR 0.65-6.65 ng/mL/month) than in patients without lung PC relapse (median PSAvel 0.3 ng/mL/month, IQR 0.2-0.5 ng/mL/month). Patients with lung metastases from PC had significantly (P=0.006) higher GS at diagnosis (median GS 8) than the other ones (median GS 7). Our analysis shows that the prevalence of F-18-FECh positive lung metastases in patients with PC, especially with higher GS at diagnosis, is higher in presence of a steady increase in PSA values, confirmed by higher PSAvel and shorter PSAdt.

PSA-stratified detection rates for [68Ga]THP-PSMA, a novel probe for rapid kit-based 68Ga-labeling and PET imaging, in patients with biochemical recurrence after primary therapy for prostate cancer.

[68Ga]Tris(hydroxypyridinone)(THP)-PSMA is a novel radiopharmaceutical for one-step kit-based radiolabelling, based on direct chelation of 68Ga3+ at low concentration, room temperature and over a wide pH range, using direct elution from a 68Ge/68Ga-generator. We evaluated the clinical detection rates of [68Ga]THP-PSMA PET/CT in patients with biochemically recurrent prostate cancer after prostatectomy. Consecutive patients (n=99) referred for evaluation of biochemical relapse of prostate cancer by [68Ga]THP-PSMA PET/CT were analyzed retrospectively. Patients underwent a standard whole-body PET/CT (1 h p.i.), followed by delayed (3 h p.i.) imaging of the abdomen. PSA-stratified cohorts of positive PET/CT results, standardized uptake values (SUVs) and target-to-background ratios (TBRs) were analyzed, and compared between standard and delayed imaging. At least one lesion suggestive of recurrent or metastatic prostate cancer was identified on PET images in 52 patients (52.5%). Detection rates of [68Ga]THP-PSMA PET/CT increased with increasing PSA level: 94.1% for a PSA value of ≥10 ng/mL, 77.3% for a PSA value of 2 to <10 ng/mL, 54.5% for a PSA value of 1 to <2 ng/mL, 14.3% for a PSA value of 0.5 to <1 ng/mL, 20.0% for a PSA value of >0.2 to <0.5, and 22.2% for a PSA value of 0.01 to 0.2 ng/mL. [68Ga]THP-PSMA uptake (SUVs) in metastases decreased over time, whereas TBRs improved. Delayed imaging at 3 h p.i. exclusively identified pathologic findings in 2% of [68Ga]THP-PSMA PET/CT scans. Detection rate was higher in patients with a Gleason score ≥8 (P=0.02) and in patients receiving androgen deprivation therapy (P=0.003). In this study, [68Ga]THP-PSMA PET/CT showed suitable detection rates in patients with biochemical recurrence of prostate cancer and PSA levels ≥ 2 ng /mL. Detections rates were lower than in previous studies evaluating other PSMA ligands, though prospective direct radiotracer comparison studies are mandatory particularly in patients with low PSA levels to evaluate the relative performance of different PSMA ligands.

Contribution of 11C-Choline PET/CT in prostate carcinoma biochemical relapse with serum PSA level below 1 ng/ml

Objective11C-Choline PET/CT has demonstrated good results in the restaging of prostate cancer (PCa) with high serum prostate specific antigen (PSA), but its use in patients with low serum PSA is controversial. Our aim was to evaluate the contribution of 11C-Choline PET/CT in patients with PCa, biochemical relapse and PSA <1ng/ml. Material and methodFifty consecutive patients (mean age: 65.9±5.6 years) with biochemical relapse of PCa and serum PSA <1ng/ml were evaluated retrospectively. PET/CT was performed 20min after intravenous administration of 555–740MBq of 11C-Choline. Minimum follow up time was 30 months. ResultsTwenty-one out of 50 patients (42%) had an abnormal 11C-Choline PET/CT. In 7 out of 21 patients (14%) tumour was confirmed (4 in prostatic bed, 4 in pelvic lymph nodes, 2 in mediastinal lymph nodes and one synchronous sigmoid carcinoma), and in all cases the initial therapy planning was modified. In 2 patients (4%) subsequent tests diagnosed benign disease (one sarcoidosis, one tuberculosis sequelae) and in 3 patients (6%) they ruled out pathology. The other 9 patients (18%) had no further assessment (7 mediastinal and 4 pelvic lymph nodes). Twenty-nine out of 50 patients (58%) had a normal PET/CT. At 30 months, follow up recurrence was confirmed in only 2 of these patients. Conclusions11C-Choline PET/CT proved its usefulness in demonstrating tumour in 14% of patients with BR of PCa and serum PSA <1ng/ml, with therapeutic implications. In 4% of patients a benign condition was detected. A normal 11C-Choline PET/CT was associated with a very low rate of recurrence at 30 months.

Serum levels of miR-320 family members are associated with clinical parameters and diagnosis in prostate cancer patients.

We studied the association of the serum levels of the microRNA family members miR-320a/-b/-c with clinico-pathological data to assess their applicability as diagnostic biomarker in prostate cancer (PCa) patients. The levels of miR-320a/-b/-c in 3 groups were evaluated by qRT-PCR (145 patients with PCa, 31 patients with benign prostatic hyperplasia (BPH) and 19 healthy controls). The levels of the three family members of miR-320 were directly correlated within each group (P < 0.001), but they differed significantly among the three groups (P < 0.001). The serum levels of the miR-320 family members were significantly increased in older patients compared to younger patients (≤ 66 years vs. > 66 years, P ≤ 0.001). In addition, the levels of all three miR-320 family members were significantly different in patients with low tumor stage compared with those with high tumor stage (miR-320a: P = 0.034; miR-320b: P = 0.006; miR-320c: P = 0.007) and in patients with low serum PSA compared with those with high serum PSA (≤ 4 ng vs. > 4 ng; miR-320a: P = 0.003; miR-320b: P = 0.003; miR-320c: P = 0.006). The levels of these miRNAs were inversely correlated with serum PSA levels. Detection in the serum samples of PCa patients with or without PSA relapse revealed higher levels of miR-320a/-b/-c in the group without PSA relapse before/after radical prostatectomy than in that with PCa relapse.In summary, the differences among the PCa/BPH/healthy control groups with respect to miR-320a/-b/-c levels in conjunction with higher levels in patients without a PSA relapse than in those with a relapse suggest the diagnostic potential of these miRNA-320 family members in PCa patients.

68Ga PSMA-11 PET with CT urography protocol in the initial staging and biochemical relapse of prostate cancer

Background68Ga-labelled prostate specific membrane antigen (PSMA) ligand PET/CT is a promising modality in primary staging (PS) and biochemical relapse (BCR) of prostate cancer (PC). However, pelvic nodes or local recurrences can be difficult to differentiate from radioactive urine. CT urography (CT-U) is an established method, which allows assessment of urological malignancies. The study presents a novel protocol of 68Ga-PSMA-11 PET/CT-U in PS and BCR of PC.MethodsA retrospective review of PSMA PET/CT-U preformed on 57 consecutive patients with prostate cancer. Fifty mL of IV contrast was administered 10 min (range 8–15) before the CT component of a combined PET/CT study, acquired approximately 60 min (range 40–85) after administration of 166 MBq (range 91–246) of 68Ga-PSMA-11. PET and PET/CT-U were reviewed by two nuclear medicine physicians and CT-U by a radiologist. First, PET images were reviewed independently followed by PET/CT-U images. Foci of activity which could not unequivocally be assessed as disease or urinary activity were recorded. PET/CT-U was considered of potential benefit in final interpretation when the equivocal focal activity in PET images corresponded to opacified ureter, bladder, prostate bed, seminal vesicles, or urethra. Student’s T test and Pearson’s correlation coefficient was used for assessment of variables including lymph node size and standardized uptake value.ResultsOverall 50 PSMA PET/CT-U studies were performed for BCR and 7 for PS. Median PSA with BCR and PS were 2.0 ± 11.4 ng/ml (0.06–57.3 ng/ml) and 18 ± 35.3 ng/ml (6.8–100 ng/ml), respectively. The median Gleason-score for both groups was 7 (range 6–10). In BCR group, PSMA PET was reported positive in 36 (72%) patients, CT-U in 11(22%) patients and PET/CT-U in 33 (66%) patients. In PS group, PSMA PET detected the primary site in all seven patients, of which one patient with metastatic nodal disease had negative CT finding. Of 40 equivocal foci (27/57 patients) on PET, 11 foci (10/57 patients, 17.5%) were localized to enhanced urine on PET/CT-U, hence considered of potential benefit in interpretation. Of those, 3 foci (3 patients) were solitary sites of activity on PSMA imaging including two local and one nodal site and 4 foci (3 patients) were in different nodal fields.ConclusionsPET/CT-U protocol is a practical approach and may assist in interpretation of 68Ga-PSMA-11 imaging by delineation of the contrast opacified genitourinary system and matching focal PSMA activity with urinary contrast.

17PD - INO-5150 (PSA and PSMA) +/- INO-9012 (IL-12) immunotherapy in biochemically relapsed prostate cancer

17PD - INO-5150 (PSA and PSMA) +/- INO-9012 (IL-12) immunotherapy in biochemically relapsed prostate cancer

Liver metastases from prostate cancer at 11C-Choline PET/CT: a multicenter, retrospective analysis

During our daily clinical practice using 11C-Choline PET/CT for restaging patients affected by relapsing prostate cancer (rPCa) we noticed an unusual but significant occurrence of hypodense hepatic lesions with a different tracer uptake. Thus, we decided to evaluate the possible correlation between rPCa and these lesions as possible hepatic metastases. We retrospectively enrolled 542 patients diagnosed with rPCa in biochemical relapse after a radical treatment (surgery and/or radiotherapy). Among these, patients with a second tumor or other benign hepatic diseases were excluded. All patients underwent 11C-Choline PET/CT during the standard restaging workup of their disease. We analyzed CT images to evaluate the presence of hypodense lesions and PET images to identify the relative tracer uptake. In accordance to the subsequent oncological history, five clinical scenarios were recognized [Table 1]: normal low dose CT (ldCT) and normal tracer distribution (Group A); evidence of previously unknown hepatic round hypodense areas at ldCT with normal rim uptake (Group B); evidence of previously known hepatic round hypodense areas at ldCT stable over time and with normal rim uptake (Group C); evidence of previously known hepatic round hypodense areas at ldCT, in a previous PET/CT scan, with or without rim uptake and significantly changing over time in terms of size and/or uptake (Group D); evidence of hepatic round hypodense areas at ldCT with or without rim uptake confirmed as prostate liver metastases by histopathology, triple phase ceCT, ce-ultra sound (CEUS) and clinical/biochemical evaluation (Group E). We evaluated the correlation with PSA level at time of scan, rim SUVmax and association with local relapse or non-hepatic metastases (lymph nodes, bone, other parenchyma). Five hundred and forty-two consecutive patients were retrospectively enrolled. In 140 of the 542 patients more than one 11C-choline PET/CT had been performed. A total of 742 11C-Choline PET/CT scans were analyzed. Of the 542 patients enrolled, 456 (84.1%) had a normal appearance of the liver both at ldCT and PET (Group A). 19/542 (3,5%) belonged to Group B, 13/542 (2.4%) to Group C, 37/542 (6.8%) to Group D and 18/542 (3.3%) to Group E. Mean SUVmax of the rim was: 4.5 for Group B; 4.2 for Group C; 4.8 for Group D; 5.9 for Group E. Mean PSA level was 5.27 for Group A, 7.9 for Group B, 10.04 for Group C, 10.01 for Group D, 9.36 for Group E. Presence of positive findings at 11C-Choline PET/CT in any further anatomical area (local relapse, lymph node, bone, other extra hepatic sites) correlated with an higher PSA (p = 0.0285). In both the univariate and multivariate binary logistic regression analyses. PSA, SUVmax of the rim, local relapse, positive nodes were not associated to liver mets (Groups D-E) (p > 0.05). On the contrary, a significant correlation was found between the presence of liver metG (group D-E) and bone lesions (p= 0.00193). Our results indicate that liver metastases in relapsing prostate cancer may occur frequently. The real incidence evaluation needs more investigations. In this case and despite technical limitations, Choline PET/CT shows alterations of tracer distribution within the liver that could eventually be mistaken for simple cysts but can be suspected when associated to high trigger PSA, concomitant bone lesions or modification over time. In this clinical setting an accurate analysis of liver tracer distribution (increased or decreased uptake) by the nuclear medicine physician is, therefore, mandatory.

High miR-205 expression in normal epithelium is associated with biochemical failure - an argument for epithelial crosstalk in prostate cancer?

Due to insufficient prognostic tools, failure to predict aggressive prostate cancer (PC) has left patient selection for radical treatment an unsolved challenge. This has resulted in overtreatment with radical therapy. Better prognostic tools are urgently warranted. MicroRNAs (miRs) have emerged as important regulators of cellular pathways, resulting in altered gene expressions. miR-205 has previously been observed downregulated in PC, acting as tumor suppressor. Herein, the expression of miR-205 in prostate tissue was examined in a large, well-described cohort of 535 Norwegian prostatectomy patients. Using in situ hybridization, miR-205 expression was semiquantatively measured in normal and tumor tissues from radical prostatectomy specimens. Associations with clinicopathological data and PC relapse were calculated. Expression of miR-205 was lower in tumor epithelium compared to normal epithelium. No association was observed between miR-205 expression in primary tumor epithelium and cancer relapse. In contrast, high expression of miR-205 in normal epithelium was independently associated with biochemical relapse (HR = 1.64, p = 0.003). A prognostic importance of miR-205 expression was only found in the normal epithelium, raising the hypothesis of epithelial crosstalk between normal and tumor epithelium in PC. This finding supports the proposed novel hypothesis of an anti-cancerogenous function of normal epithelium in tumor tissue.

99m Tc-MIP-1404-SPECT/CT for the detection of PSMA-positive lesions in 225 patients with biochemical recurrence of prostate cancer.

99m Tc-MIP-1404 (Progenics Pharmaceuticals, Inc., New York, NY) is a novel, SPECT-compatible 99m Tc-labeled PSMA inhibitor for the detection of prostate cancer. We present results of its clinical use in a cohort of 225 men with histologically confirmed prostate cancer referred for workup of biochemical relapse. From April 2013 to April 2017, 99m Tc-MIP1404-scintigraphy was performed in 225 patients for workup of PSA biochemical relapse of prostate cancer. Whole-body planar and SPECT/CT images of the lower abdomen and thorax were obtained 3-4 h p.i. of 710 ± 64 MBq 99m Tc-MIP-1404. Images were visually analyzed for presence and location of abnormal uptake. In addition, quantitative analysis of the SPECT/CT data was carried out on a subset of 125 patients. Follow-up reports of subsequent therapeutic interventions were available for 59% (139) of all patients. Tracer-positive lesions were detected in 77% (174/225) of all patients. Detections occurred at the area of local recurrence in the prostate in 25% of patients (or a total of 56), with metastases in lymph nodes in 47% (105), bone in 27% (60), lung in 5% (12), and other locations in 2% (4) of patients. Detection rates were 90% at PSA levels ≥2 ng/mL and 54% below that threshold. Lesional SUVmax values were, on average, 32.2 ± 29.6 (0.8-142.2), and tumor-to-normal ratios 146.6 ± 160.5 (1.9-1482.4). The PSA level correlated significantly with total uptake of MIP-1404 in tumors (P < 0.001). Furthermore, total tumor uptake was significantly higher in patients with Gleason scores ≥8 compared to those with Gleason scores ≤7 (P < 0.05). In patients with androgen deprivation therapy, the detection rate was significantly higher compared to patients without androgen deprivation therapy (86% vs 71%, P < 0.001). Based on 99m Tc-MIP-1404-imaging and other information, an interdisciplinary tumor board review recommended changes to treatment plans in 74% (104/139) of those patients for whom the necessary documentation was available. SPECT/CT with 99m Tc-labeled MIP-1404 has a high probability in detecting PSMA-positive lesions in patients with elevated PSA. Statistical analysis disclosed significant relationship between quantitative 99m Tc-MIP-1404 uptake, PSA level, and Gleason score.

Clinical analysis of advanced prostate cancer treated by surgery in 25 patients

Objective To investigate surgical treatment for advanced prostate cancer. Methods We retrospectively reviewed 25 cases of advanced prostate cancer treated by surgery between May 2014 and February 2016. The general data of the patients were analyzed.And age, PSA before surgery, pathological stage, prostate volume, fluctuation of postoperational PSA and outcome were recorded. Results The average age of the patients was 68.1 (56~83)years old, mean PSA before surgery was 86(15.81~335)ng/mL. There was 7, 18 patients with Gleason score of 7 and ≥8 respectively. Of those patients, 8 of them were staged T3bN0, 13 of them were TxN1M0, 4 patients had putative bone metastases and were staged M1b clinically. Mean volume of the prostate was 67.2(50~145 )mL, 19 of them were treated by laproscopic radical prostatectomy, 6 patients was treated by open retropubic surgery. Extended lymphatic dissection were performed, 4~30 lymph nodes with an average of 13 were extirpated. Three patients need transfusion after surgery, 1 patient experienced delayed drainage withdraw because of lymphorrhea, no major complication was found. PSA decreased significantly after surgery, mean PSA level dropped to 1.2(0.32~4.6)ng/mL at 6 weeks after operation, and then to 0.08(0.003~0.450)ng/mL at 3 months after surgery. The patients were followed up for 5~23 months, none of them died. One patient experienced biochemical relapse, MRI showed relapse in the urethrovesical anastomosis and was treated by endoscopic resection and comfirmed to be prostate cancer relapse with the same Gleason score of 9 as the former pathological diagnosis. Conclusions Surgery is a safe modality to treat advanced prostate cancer, radical prostatectomy and extended lymph node dissection didn't necessarily mean higher risk of complication. In experienced hands, radical prostatectomy and extended lymph node dissection is a rational choice for selected patients. Key words: Prostatic Neoplasms; Prostatectomy

790PD - Safety and immunogenicity of a DNA-vaccine immunotherapy in men with biochemically (PSA) relapsed prostate cancer

Background: DNA vaccines INO-5150 (PSA and PSMA) +/- INO-9012 (IL-12) were administered to biochemically recurrent prostate cancer patients (pts) to demonstrate breaking tolerance, assessing antigen-specific humoral and cellular immune responses with the potential for stabilization of disease progression. Methods: Phase I, open-label, multi-center study in pts post-definitive therapy with a rising PSA after surgery and/or RT and PSA doubling time (DT)> 3 months (mos), testosterone > 150 ng/dL, no concomitant ADT and no evidence of metastases. Safety, immunogenicity and efficacy were evaluated in 4 treatment arms in 60 planned pts (A: 16, 2mg INO-5150; B: 15, 8.5 mg INO-5150; C: 15, 2mg INO-5150 + 1mg INO-9012; D: 16, 8.5mg INO-5150 + 1mg INO-9012) treated with 4 IM doses followed by electroporation on day 0, wks 3, 12 and 24 who were followed for a total of 72 Wks. Results: Median age, Gleason score and time since diagnosis were 69.5 yrs (range: 55.4-87.7), 7 (5-10) and 8.4 yrs (0.4-23.8) respectively. Of 61 evaluable pts, 38 (62%) had PSADT ≤ 12 mos and 23 (38%) had DT > 12 mos at Day 0. For pts with DT ≤ 12 mos, Day 0 and week 27 median DT were 6.0 (1.5, 11.6) mos and 8.1 (2.2, 100.0) mos respectively. Flow cytometry analysis revealed antigen specific upregulation of CD38 and Perforin on CD8+ T cells in 19/50 (38%) pts across the trial, with the greatest proportion in arm A, 8/14 (57%). Additional analysis for this cell subset showed a high PD-1 expression of 68.6% in this arm at week 27. Of note, in 8/15 (53%) arm A pts with DT ≤ 12 mos, their median DT at Day 0 was 6.2 (2.9, 10.2) mos and 19.2 (6.6, 100.0) mos at Wk 27. Safety: 7 Grade (Gr) 3 SAEs in 5 pts and 0 Gr 4-5 SAEs reported. Most AEs were Gr 1-3 in 51/62 (82%) pts and majority of those were associated with injection site reactions. Conclusions: INO-5150 +/- INO-9012 was safe at dosages examined. Data demonstrated both PSA and PSMA are immunogenic and INO-5150 induced cellular immune responses. Higher proportion of arm A pts showed immunological responses as well as improvements in PSA DT, specifically pts with DT ≤ 12 mos suggesting correlation of immunological efficacy and clinical benefit. Continued analyses are planned as patient follow-up is ongoing. (NCT02514213) Clinical trial identification: NCT02514213; July 29, 2015 Legal entity responsible for the study: Inovio Pharmaceuticals Funding: Inovio Pharmaceuticals Disclosure: K. Bhatt: Inovio (study sponsor employee), own stocks M. Morrow, T. McMullan, K. Kraynyak, J. Lee, B. Sacchetta, L. Liu, S. Rosencranz: Inovio (study sponsor) employee, own stocks in company. Y. Whang: Research funding from Janssen, Astellas, Tokai, Inovio. I. Csiki, M. Bagarazzi: Employed by Inovio Pharmaceuticals. All other authors have declared no conflicts of interest.

Incidental prostate cancer in patients with muscle-invasive bladder cancer who underwent radical cystoprostatectomy.

The aim of this study was to analyze the features of incidentally detected prostate cancer (PCa) in radical cystoprostatectomy (RCP) specimens to determine their pathological characteristics and clinical significance. In this retrospective study, we reviewed the clinical and pathological records of 431 consecutive patients with muscle-invasive bladder cancer who underwent RCP at Hirosaki University. Of these, we focused on 237 male patients with prostate-specific antigen (PSA) measurements and digital rectal examinations (DRE) that were recorded prior to the RCP. Significant PCa was defined as a tumor with a Gleason 4 or 5 pattern, pathological T3 or higher stage, lymph node involvement or three or more multifocal lesions within the prostate specimen. We compared clinically significant and insignificant PCa. In this study, a total of 43 patients (18.1%) were diagnosed with incidental PCa via RCP specimens. Age, preoperative PSA levels and pathological T stage in patients with clinically significant PCa were considerably higher than in those with insignificant cancer. Apical involvement was found in 16 patients, including 11 of those with clinically significant PCa. By the end of the follow-up period, none of the enrolled patients had a biochemical recurrence after surgery or died from PCa. According to our findings, preoperative risk factors were not reliable enough to accurately predict clinically significant PCa. Although there was no biochemical relapse or clinical recurrence of PCa in this study, the potential oncologic risk of prostate-sparing RCP must be considered.

A rare castration-resistant progenitor cell population is highly enriched in Pten-null prostate tumours.

Castration-resistant prostate cancer is a lethal disease. The cell type(s) that survive androgen deprivation remain poorly described, despite global efforts to understand the various mechanisms of therapy resistance. We recently identified in wild-type (WT) mouse prostates a rare population of luminal progenitor cells that we called LSCmed according to their FACS profile (Lin- /Sca-1+ /CD49fmed ). Here, we investigated the prevalence and castration resistance of LSCmed in various mouse models of prostate tumourigenesis (Pb-PRL, Ptenpc-/- , and Hi-Myc mice). LSCmed prevalence is low (∼8%, similar to WT) in Hi-Myc mice, where prostatic androgen receptor signalling is unaltered, but is significantly higher in the two other models, where androgen receptor signalling is decreased, rising up to more than 80% in Ptenpc-/- prostates. LSCmed tolerate androgen deprivation and persist or are enriched 2-3 weeks after castration. The tumour-initiating properties of LSCmed from Ptenpc-/- mice were demonstrated by regeneration of tumours in vivo. Transcriptomic analysis revealed that LSCmed represent a unique cell entity as their gene expression profile is different from luminal and basal/stem cells, but shares markers of each. Their intrinsic androgen signalling is markedly decreased, explaining why LSCmed tolerate androgen deprivation. This also illuminates why Ptenpc-/- tumours are castration-resistant since LSCmed represent the most prevalent cell type in this model. We validated CK4 as a specific marker for LSCmed on sorted cells and prostate tissues by immunostaining, allowing for the detection of LSCmed in various mouse prostate specimens. In castrated Ptenpc-/- prostates, there was significant proliferation of CK4+ cells, further demonstrating their key role in castration-resistant prostate cancer progression. Taken together, this study identifies LSCmed as a probable source of prostate cancer relapse after androgen deprivation and as a new therapeutic target for the prevention of castrate-resistant prostate cancer. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Abiraterone for Prostate Cancer Not Previously Treated with Hormone Therapy

BackgroundAbiraterone acetate plus prednisolone improves survival in men with relapsed prostate cancer. We assessed the effect of this combination in men starting long-term androgen-deprivation therapy (ADT), using a multigroup, multistage trial design.MethodsWe randomly assigned patients in a 1:1 ratio to receive ADT alone or ADT plus abiraterone acetate (1000 mg daily) and prednisolone (5 mg daily) (combination therapy). Local radiotherapy was mandated for patients with node-negative, nonmetastatic disease and encouraged for those with positive nodes. For patients with nonmetastatic disease with no radiotherapy planned and for patients with metastatic disease, treatment continued until radiologic, clinical, or prostate-specific antigen (PSA) progression; otherwise, treatment was to continue for 2 years or until any type of progression, whichever came first. The primary outcome measure was overall survival. The intermediate primary outcome was failure-free survival (treatment failure was defined as radiologic, clinical, or PSA progression or death from prostate cancer).ResultsA total of 1917 patients underwent randomization from November 2011 through January 2014. The median age was 67 years, and the median PSA level was 53 ng per milliliter. A total of 52% of the patients had metastatic disease, 20% had node-positive or node-indeterminate nonmetastatic disease, and 28% had node-negative, nonmetastatic disease; 95% had newly diagnosed disease. The median follow-up was 40 months. There were 184 deaths in the combination group as compared with 262 in the ADT-alone group (hazard ratio, 0.63; 95% confidence interval [CI], 0.52 to 0.76; P<0.001); the hazard ratio was 0.75 in patients with nonmetastatic disease and 0.61 in those with metastatic disease. There were 248 treatment-failure events in the combination group as compared with 535 in the ADT-alone group (hazard ratio, 0.29; 95% CI, 0.25 to 0.34; P<0.001); the hazard ratio was 0.21 in patients with nonmetastatic disease and 0.31 in those with metastatic disease. Grade 3 to 5 adverse events occurred in 47% of the patients in the combination group (with nine grade 5 events) and in 33% of the patients in the ADT-alone group (with three grade 5 events).ConclusionsAmong men with locally advanced or metastatic prostate cancer, ADT plus abiraterone and prednisolone was associated with significantly higher rates of overall and failure-free survival than ADT alone. (Funded by Cancer Research U.K. and others; STAMPEDE ClinicalTrials.gov number, NCT00268476, and Current Controlled Trials number, ISRCTN78818544.)

Abstract 1584: Wnt/beta-catenin and Foxa2 axis activates AR signaling in castration resistant prostate cancer

Abstract Background: Prostate cancer (PCa) is the leading cancer among men in the world. Androgen deprivation therapy is a common treatment to cease prostate growth. However, androgen deprivation eventually fails and PCa relapses, evolving into castration resistant prostate cancer (CRPCa). It has been established that androgen receptor (AR) continues to be the central player in mediating CRPCa. However, the mechanism by which the AR signaling remains active is unclear. We have reported that activation of Wnt/beta-catenin signaling pathway promotes castrate-resistant progression. Our study has also shown that activation of the Wnt/beta-catenin pathway induces the expression of Foxa2, a fork-head transcription factor that is expressed in embryonic prostate &amp; advanced stage PCa. Here, we study the Wnt pathway and the role of Foxa2 in retaining active AR signaling in advanced PCa in the absence of androgens. TRAMP mice, SV40 T-antigen transgenic mouse models for PCa, were used. It has been recognized that in this model, T-antigen, which is driven by androgen-responsive probasin promoter, remains expressed following androgen ablation. In this study, we identified a mechanism that sustains an active AR signaling in CRPCa. Methods: To study whether the Wnt/beta-catenin pathway is active in advanced stage PCa, we crossed the TRAMP mice with GFP-Wnt reporter mice. Some of the TRAMP/Wnt-reporter mice were castrated to study how androgen deprivation affects Wnt/beta-Catenin signaling and promotes PCa progression. Prostates were analyzed using IHC and IF staining. We also established a prostate epithelial cell line that stably expresses Foxa2. Cell proliferation was examined with IncuCyte Zoom software. The expression of AR target genes was assessed by using quantitative RT-PCR and Western blotting. ChIP was conducted to assess the recruitment of transcriptional machinery to the promoters of AR-regulated genes. Results: Utilizing the TRAMP/Wnt mouse model, we show that Wnt/beta-Catenin signaling is active in advanced stage PCa. Additionally, our data showed that Foxa2, the downstream target of Wnt/beta-Catenin signaling, drives the expression of androgen-responsive genes, regardless of androgen deprivation. Furthermore, cell proliferation assays revealed that the expression of Foxa2 enabled an androgen-independent growth of prostatic cells. Using this model system, we further explored the mechanism that activates the transcription of AR-responsive genes in the absence of androgens. Our data indicated that Foxa2 is capable of recruiting H3k27Ac to AR-responsive promoters. Conclusion: Together, these data indicate that Wnt signaling is activated in advanced stage PCa, driving Foxa2 expression, and promoting AR signaling to persist. This represents a novel mechanism that enables advanced PCa to retain AR signaling pathway following androgen ablation. Targeting both Wnt signaling and Foxa2 may pose as novel therapeutics for CRPCa. Citation Format: Zachary M. Connelly, Shu Yang, Jiahe Li, Robert Matusik, Xiuping Yu. Wnt/beta-catenin and Foxa2 axis activates AR signaling in castration resistant prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1584. doi:10.1158/1538-7445.AM2017-1584

MiR-100-5p inhibition induces apoptosis in dormant prostate cancer cells and prevents the emergence of castration-resistant prostate cancer

Carcinoma of the prostate is the most common cancer in men. Treatment of aggressive prostate cancer involves a regiment of radical prostectomy, radiation therapy, chemotherapy and hormonal therapy. Despite significant improvements in the last decade, the treatment of prostate cancer remains unsatisfactory, because a significant fraction of prostate cancers develop resistance to multiple treatments and become incurable. This prompts an urgent need to investigate the molecular mechanisms underlying the evolution of therapy-induced resistance of prostate cancer either in the form of castration-resistant prostate cancer (CRPC) or transdifferentiated neuroendocrine prostate cancer (NEPC). By analyzing micro-RNA expression profiles in a set of patient-derived prostate cancer xenograft tumor lines, we identified miR-100-5p as one of the key molecular components in the initiation and evolution of androgen ablation therapy resistance in prostate cancer. In vitro results showed that miR-100-5p is required for hormone-independent survival and proliferation of prostate cancer cells post androgen ablation. In Silico target predictions revealed that miR-100-5p target genes are involved in key aspects of cancer progression, and are associated with clinical outcome. Our results suggest that mir-100-5p is a possible therapeutic target involved in prostate cancer progression and relapse post androgen ablation therapy.

68Ga-PSMA PET/CT and Volumetric Morphology of PET-Positive Lymph Nodes Stratified by Tumor Differentiation of Prostate Cancer.

68Ga-prostate-specific membrane antigen (PSMA) PET/CT is a new method to detect early nodal metastases in patients with biochemical relapse of prostate cancer. In this retrospective investigation, the dimensions, volume, localization, and SUVmax of nodes identified by 68Ga-PSMA were correlated to their Gleason score (GS) at diagnosis. Methods: All PET/CT images were acquired 60 ± 10 min after intravenous injection of 68Ga-PSMA (mean dose, 176 MBq). In 147 prostate cancer patients (mean age, 68 y; range, 44-87 y) with prostate-specific antigen relapse (mean prostate-specific antigen level, 5 ng/mL; range, 0.25-294 ng/mL), 362 68Ga-PSMA PET-positive lymph nodes (LNs) were identified. These patients were classified on the basis of their histopathology at primary diagnosis into either low- (GS ≤ 6, well differentiated), intermediate- (GS = 7, moderately differentiated), or high-GS cohorts (GS ≥ 8, poorly differentiated prostate cancer). Using semiautomated LN segmentation software (Fraunhofer MEVIS), we measured node volume and short-axis dimensions (SADs) and long-axis dimensions based on CT and compared with the SUVmax Nodes demonstrating uptake of 68Ga-PSMA with an SUVmax of 2.0 or more were considered PSMA-positive, and nodes with an SAD of 8 mm or more were considered positive by morphologic criteria. Results: Mean SUVmax was 13.5 (95% confidence interval [CI], 10.9-16.1), 12.4 (95% CI, 9.9-14.9), and 17.8 (95% CI, 15.4-20.3) within the low-, intermediate-, and high-GS groups, respectively. The morphologic assessment of the 68Ga-PSMA-positive LN demonstrated that the low-GS cohort presented with smaller 68Ga-PSMA-positive LNs (mean SAD, 7.7 mm; n = 113), followed by intermediate- (mean SAD, 9.4 mm; n = 122) and high-GS cohorts (mean SAD, 9.5 mm; n = 127). On the basis of the CT morphology criteria, only 34% of low-GS patients, 56% of intermediate-GS patients, and 53% of high-GS patients were considered CT positive. Overall, 68Ga-PSMA imaging led to a reclassification of stage in 90 patients (61%) from cN0 to cN1 over CT. Conclusion:68Ga-PSMA PET is a promising modality in biochemical recurrent prostate cancer patients for N staging. Conventional imaging underestimates LN involvement compared with PSMA molecular staging score in each GS cohort. The sensitivity of 68Ga-PSMA PET/CT enables earlier detection of subcentimeter LN metastases in the biochemical recurrence setting.

GATA2 expression and biochemical recurrence following salvage radiation therapy for relapsing prostate cancer.

High GATA2 expression has been associated with an increased risk of poor clinical outcomes after radical prostatectomy; however, this has not been studied in relation to risk of biochemical recurrence (BCR) after salvage radiation therapy (SRT) for recurrent prostate cancer after radical prostatectomy. Our aim was to evaluate the association between protein expression levels of GATA2 in primary prostate cancer tumour samples and the risk of BCR after SRT. 109 males who were treated with SRT were included. The percentage of cells with nuclear staining and GATA2 staining intensity were both measured. These two measures were multiplied together to obtain a GATA2 H-score (range 0-12) which was our primary GATA2 staining measure. In unadjusted analysis, the risk of BCR was higher for patients with a GATA2 H-score >4 (hazard ratio = 2.04, p = 0.033). In multivariable analysis adjusting for SRT dose, pre-SRT PSA, pathological tumour stage and Gleason score, this association weakened substantially (hazard ratio = 1.45, p = 0.31). This lack of an independent association with BCR appears to be the result of correlations between GATA2 H-score >4 and higher pre-SRT PSA (p = 0.021), higher Gleason score (p = 0.044) and more severe pathological tumour stage (p = 0.068). Higher levels of GATA2 expression appear to be a marker of prostate cancer severity; however, these do not provide independent prognostic information regarding BCR beyond that of validated clinicopathological risk factors. Advances in knowledge: A higher GATA2 expression level appears to be correlated with known measures of prostate cancer severity and therefore is likely not an independent marker of outcome after SRT.

Therapies for castration-resistant prostate cancer in a new era: The indication of vintage hormonal therapy, chemotherapy and the new medicines.

When advanced prostate cancer recurred during hormonal therapy and became the castration-resistant prostate cancer, "vintage hormonal therapy," such as antiandrogen alternating therapy or estrogen-related hormonal therapy, was widely carried out in Japan until 2013. This vintage hormonal therapy controlled the progression of castration-resistant prostate cancer. When castration-resistant prostate cancer relapses during these therapies, chemotherapy using docetaxel has been carried out subsequently. Since new hormonal therapies using abiraterone acetate and enzalutamide, which improve the prognosis of castration-resistant prostate cancer, became available in Japan from 2014, therapeutic options for castration-resistant prostate cancer have increased. Furthermore, the improvement of the further prognosis is promising by using cabazitaxel for docetaxel-resistant castration-resistant prostate cancer and radium-223 for castration-resistant prostate cancer with bone metastasis. An increase in therapeutic options gives rise to many questions, including best timing to use them and the indication. Furthermore, physicians have to consider the treatment for the recurrence after having carried out chemotherapy. We want to argue the difference in hormonal therapy between Japan and Western countries, and problems when carrying out new treatments, and the importance of imaging in the present review article.