Castration-sensitive Prostate Cancer Patients Research Articles

Role of Bone Scan Index (BSI) in the Prognosis and Treatment Efficacy in Castration-Sensitive Prostate Cancer Patients with Bone Metastasis

Bone is the most common metastatic site in prostate cancer (PCa). Although the extent of disease (EOD) grade is used for evaluating burden of bone metastasis, the accuracy of bone metastasis classification needs improvement. Bone scan index (BSI) was developed as a quantitative tool to enhance the interpretability and clinical relevance of the bone scan. This study aimed to explore the role of BSI using BONENAVI® software in determining the prognosis and treatment efficacy in castration-sensitive PCa (mCSPC) patients with bone metastasis. We retrospectively reviewed 61 mCSPC patients with bone metastasis who had received primary androgen deprivation therapy (PADT) at our institution. All patients received PADT with luteinizing hormone-releasing hormone agonist or surgical castration accompanied by first-generation antiandrogen, bicalutamide. Bone scans were performed with ⁹⁹[m]Tc-MDP. BSI (%) was divided into two groups (＜1.0 and ≧1.0), and BSI response rates(change at 0 months to after 6 months) were determined using thresholds of 45% decline. Castration-resistant prostate cancer (CRPC) -free survival (CRPC-FS) and Overall survival (OS) rates were analyzed using the Kaplan-Meier method. The median follow-up was 41. 9 months. Overall, 16 patients (26. 2%) died. Multivariate analysis on pretreatment factors revealed that hemoglobin (P＝0.03) and BSI (P＝0.04) were independent prognostic factors for OS. The 5-year OS rates in patients with low BSI and high BSI were 84.6% and 39.2%, respectively (P＝0.02). In 40 patients who had a bone scan before and after PADT, OS rates in patients with a good response (≧45%) were significantly higher than those with a poor response (＜45%) (P＝0.001). Nadir PSA titers within 6 months after the start of treatment (P＝0.005), Hb (P＝0.003), and BSI change (P＝0.014) were independent prognostic factors for OS. In mCSPC patients with bone metastases, BSI at diagnosis was an important predictor of CRPC progression and OS as a pre-treatment factor, and BSI change rate and PSA nadir as post-treatment factors.

Measuring antigen expression of cancer cell lines and circulating tumour cells

When evaluating EpCAM-based enrichment technologies for circulating tumour cells (CTCs), the cell lines used should closely resemble real CTCs, meaning the EpCAM expression of CTCs needs to be known, but also the EpCAM expression of cell lines at different institutions and times is important. As the number of CTCs in the blood is low, we enriched CTCs through the depletion of leukocytes from diagnostic leukapheresis products of 13 prostate cancer patients and measured EpCAM expression using quantitative flow cytometry. Antigen expression was compared between multiple institutions by measuring cultures from each institution. Capture efficiency was also measured for one of the used cell lines. Results show CTCs derived from castration-sensitive prostate cancer patients have varying but relatively low EpCAM expression, with median expression per patient ranging from 35 to 89,534 (mean 24,993) molecules per cell. A large variation in the antigen expression of identical cell lines cultured at different institutions was found, resulting in recoveries when using the CellSearch system ranging from 12 up to 83% for the same cell line. We conclude that large differences in capture efficiency can occur while using the same cell line. To closely resemble real CTCs from castration-sensitive prostate cancer patients, a cell line with a relatively low EpCAM expression should be used, and its expression should be monitored frequently.

Effect of Dexamethasone on Abiraterone Pharmacokinetics in Mice: Determined by LC/MS Analysis

Background: Abiraterone acetate is a cytochrome P450 17A1 (CYP17A1) inhibitor that is indicated for use in both castration-resistant and castration-sensitive prostate cancer patients. To manage the mineralocorticoid effects of CYP17A1 inhibition, a glucocorticoid such as dexamethasone is co-administered with abiraterone. The goal of the present study was to understand the effect of dexamethasone on the disposition of abiraterone. Methods: Adult male CD-1 mice were treated with either dexamethasone (80 mg/kg/day) or vehicle for three consecutive days, followed by the administration of a single dose of abiraterone acetate (180 mg/kg) as an oral gavage. Blood samples were collected by tail bleeding at timepoints between 0 to 24 h. Subsequently, abiraterone was extracted from the mouse serum using a neutral pH condition and serum abiraterone levels were determined using a liquid chromatography-mass spectrometry assay. Results: Our results demonstrated that dexamethasone lowered the maximum plasma concentration and area under the curve parameters by approximately five- and ten-fold, respectively. Similar effects were also observed on the plasma half-life and oral clearance parameters. This is the first report of dexamethasone effect on abiraterone disposition in vivo. Conclusions: We conclude that dexamethasone has the potential to reduce the plasma abiraterone level and thus compromise its CYP17A1 inhibitory ability in the procancerous androgen biosynthesis pathway. Thus, use of a higher abiraterone dose may be warranted when used alongside dexamethasone.

MicroRNA-375 is a therapeutic target for castration-resistant prostate cancer through the PTPN4/STAT3 axis

The functional role of microRNA-375 (miR-375) in the development of prostate cancer (PCa) remains controversial. Previously, we found that plasma exosomal miR-375 is significantly elevated in castration-resistant PCa (CRPC) patients compared with castration-sensitive PCa patients. Here, we aimed to determine how miR-375 modulates CRPC progression and thereafter to evaluate the therapeutic potential of human umbilical cord mesenchymal stem cell (hucMSC)-derived exosomes loaded with miR-375 antisense oligonucleotides (e-375i). We used miRNA in situ hybridization technique to evaluate miR-375 expression in PCa tissues, gain- and loss-of-function experiments to determine miR-375 function, and bioinformatic methods, dual-luciferase reporter assay, qPCR, IHC and western blotting to determine and validate the target as well as the effects of miR-375 at the molecular level. Then, e-375i complexes were assessed for their antagonizing effects against miR-375. We found that the expression of miR-375 was elevated in PCa tissues and cancer exosomes, correlating with the Gleason score. Forced expression of miR-375 enhanced the expression of EMT markers and AR but suppressed apoptosis markers, leading to enhanced proliferation, migration, invasion, and enzalutamide resistance and decreased apoptosis of PCa cells. These effects could be reversed by miR-375 silencing. Mechanistically, miR-375 directly interfered with the expression of phosphatase nonreceptor type 4 (PTPN4), which in turn stabilized phosphorylated STAT3. Application of e-375i could inhibit miR-375, upregulate PTPN4 and downregulate p-STAT3, eventually repressing the growth of PCa. Collectively, we identified a novel miR-375 target, PTPN4, that functions upstream of STAT3, and targeting miR-375 may be an alternative therapeutic for PCa, especially for CRPC with high AR levels.

Apalutamide or enzalutamide in castration-sensitive prostate cancer: a number needed to treat analysis.

The treatment of castration-sensitive prostate cancer (CSPC) has been revolutionized by the advent of apalutamide and enzalutamide in this setting; however, a direct comparison between these agents is still missing. In the current paper, we performed both Number Needed to Treat (NNT) and Number Needed to Harm (NNH) analyses aimed to compare clinical outcomes in CSPC patients treated with apalutamide or enzalutamide; data from 3323 CSPC patients enrolled in the ARCHES, ENZAMET and TITAN phase III studies were included. According to our results, apalutamide showed better results in terms of overall survival (OS) and safety in patients with CSPC, while better outcomes were observed with enzalutamide in the low-volume subgroup.

Local Control after Locally Ablative, Image-Guided Radiotherapy of Oligometastases Identified by Gallium-68-PSMA-Positron Emission Tomography in Castration-Sensitive Prostate Cancer Patients (OLI-P).

Simple SummaryIn this clinical trial, 63 patients with a total of 89 prostate cancer metastases identified on PSMA-PET were included, none of them undergoing androgen deprivation therapy. We showed that local ablative radiotherapy controls >90% of the metastases, but progression at other sites is common after two years. Local ablative radiotherapy may be an option to at least temporarily avoid systemic therapy in selected patients.Progression of prostate-specific antigen (PSA) values after curative treatment of prostate cancer patients is common. Prostate-specific membrane antigen (PSMA-) PET imaging can identify patients with metachronous oligometastatic disease even at low PSA levels. Metastases-directed local ablative radiotherapy (aRT) has been shown to be a safe treatment option. In this prospective clinical trial, we evaluated local control and the pattern of tumor progression. Between 2014 and 2018, 63 patients received aRT of 89 metastases (MET) (68 lymph node (LN-)MET and 21 bony (OSS-)MET) with one of two radiation treatment schedules: 50 Gy in 2 Gy fractions in 34 MET or 30 Gy in 10 Gy fractions in 55 MET. The mean gross tumor volume and planning target volume were 2.2 and 14.9 mL, respectively. The median follow-up time was 40.7 months. Local progression occurred in seven MET, resulting in a local control rate of 93.5% after three years. Neither treatment schedule, target volume, nor type of lesion was associated with local progression. Regional progression in the proximity to the LN-MET was observed in 19 of 47 patients with at least one LN-MET (actuarial 59.3% free of regional progression after 3 years). In 33 patients (52%), a distant progression was reported. The median time to first tumor-related clinical event was 16.6 months, and 22.2% of patients had no tumor-related clinical event after three years. A total of 14 patients (22%) had another aRT. In conclusion, local ablative radiotherapy in patients with PSMA-PET staged oligometastatic prostate cancer may achieve local control, but regional or distant progression is common. Further studies are warranted, e.g., to define the optimal target volume coverage in LN-MET and OSS-MET.

Abstract 979: Bcl-2 inhibitor enhances anti-androgen therapy induced regression of castration sensitive prostate cancer

Abstract Prostate cancer (PC) is the second most common cause of cancer-related deaths in males in the United States (U.S.). In the United States, an estimated 191,930 new cases will be diagnosed in 2020, resulting in 33,330 deaths, representing 10.4% of all cancer-related deaths in men in the U.S. Over the past decade, preclinical studies have demonstrated that androgen receptor (AR) signaling is a principal driver of prostate cancer, and androgen deprivation therapy (ADT) has been a mainstay in the treatment of PC. Although most PCs are initially sensitive to ADT, the duration of response is variable, and relapse invariably occurs in the transition to metastatic castration-resistant prostate cancer (mCRPC) the most lethal form of the disease. A significant proportion of mCRPCs exhibit alteration (amplification and mutation) of the AR gene. Notably, localized castration sensitive prostate cancer (CSPC) rarely demonstrates alterations of AR. This observation indicates that the alteration of AR likely results from exposure to systemic therapies rather than acting as a driver from primary CSPC to more aggressive disease. For mCRPC patients, many initially respond to second-line AR inhibitors (eg. enzalutamide and abiraterone) or docetaxel-based chemotherapy, however durable responses are rare. Therefore, it is vital to investigate additional therapeutic strategies to delay or prevent the transition of CSPC to mCRPC. Earlier studies showed that the survival of malignant cells after anti-cancer therapies could be due to increase expression in anti-apoptotic proteins, such as the Bcl-2 family of proteins. In our current study, we observed that treatment with androgen inhibits but AR inhibitors (eg enzalutamide, apalutamide) restore Bcl2 expression in human CSPC cell lines indicating possible direct negative-regulation of the Bcl2 by the AR-signaling pathway. Experimentally we also showed that overexpression of BCL2 in human CSPC cells acts as an early mediator of ADT resistance in CSPC. Cell growth assays showed an overall strong additive effect on growth inhibition with enzalutamide in-combination with the Bcl-2 inhibitor (venetoclax) on human CSPC cells. Our in-vivo isograft tumor growth results were consistent with the in-vitro data where we observed a significant decrease in tumor volume and an increase of overall survival when mice treated with enzalutamide and venetoclax in combination as compared to either of the drugs when treated alone. Our current study for the first time develops a rationale for combining ADT with Bcl2 targeted therapies for CSPC. We believe this combination will show great potential for future clinical trials of high-risk CSPC patients and may block or delay the ADT-induced shift from CSPC to mCRPC. Citation Format: Rahim Hirani, Subhiksha Nandakumar, Teja Kalidindi, Deborah Fidele, Harisha Rajanala, Ying Mazzu, Yuki Yoshikawa, Lina Jehane, Gwo-Shu Mary Lee, Elisa de Stanchina, Adam Sowalsky, Michael J. Morris, Heiko Schoder, Naga Vara Kishore Pillarsetty, Lorelei A. Mucci, Daniel Danila, Goutam Chakraborty, Philip W. Kantoff. Bcl-2 inhibitor enhances anti-androgen therapy induced regression of castration sensitive prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 979.

Body composition and metastatic prostate cancer survivorship

There is a growing body of evidence related to the importance of body composition in cancer survivorship. Current evidence exclusive to the metastatic prostate cancer setting is limited, yet sheds light on the importance of body composition to reduce risk of mortality and disease progression in this patient population. In our commentary we present the current state of evidence related to body composition and metastatic prostate cancer survival among metastatic castration-resistant and castration-sensitive prostate cancer patients among varying treatment modalities. Additionally, we discuss the proposed biological mechanisms that may underpin how favorable changes in body composition may be helpful for survivorship, and review promising lifestyle strategies that can be implemented as part of survivorship care to improve body composition in this patient population.

Genomic analysis of castration sensitive and resistant prostate cancer patients by multiple-gene targeted sequencing.

e17525 Background: Previous studies showed the significant diversity of the genomic landscapes between castration sensitive prostate cancer (CSPC) and castration resistant prostate cancer (CRPC). AR, TP53/RB1, and BRCA2/ATM have been reported to contribute to the development of CRPC. In addition, CDK12 has recently reported to lead to the worse response to AR-targeted therapies. We are aimed to clarify the landscape of somatic gene alterations in CSPC and CRPC by multiple-gene targeted sequencing and discover the differential genes between the two treatment stages in order to guide clinical treatment. Methods: We recruited 413 prostate cancer patients including 230 CSPC and 183 CRPC. Cell-free DNA was extracted from plasma samples. Targeted sequencing of 50 genes was performed, which involved in DNA damage repair (DDR) pathway, AR pathway, TP53/RB1, etc. Chi square test or Fisher test were used to analyze the differences between two cohorts. Results: A total of 33.04% (76/230) CSPC patients carried somatic gene alterations, including 16.96% (39/230) in DDR pathway, 19.57% (45/230) in AR pathway and 7.39% (17/230) in TP53/RB1. The most frequent altered gene in CSPC was FOXA1 (9.13%,21/230), followed by NCOR2 (6.52%,15/230) and TP53 (5.65%,13/230). For CRPC patients, 66.67% (122/183) carried somatic gene alterations, including 44.81% (82/230) in DDR pathway, 49.73% (91/230) in AR pathway and 25.68% (47/183) in TP53/RB1. The most frequent mutated gene in CRPC was AR (33.33%,61/183), followed by FOXA1 (23.50%,43/183) and CDK12 (17.49%,32/183). Mutation frequencies of certain genes in CRPC patients were significantly higher than CSPC patients, including CDK12 (p < 0.001), BRCA2 (p = 0.006), ATM (p = 0.003), ATR (p = 0.007), AR (p < 0.001), FOXA1 (p = 0.001), SPOP (p = 0.002), ZBTB16 (p = 0.02), TP53 (p = 0.001), RB1 (p = 0.04) and PTEN (p = 0.001). Conclusions: It was the first study which explored the genomic alterations in Chinese CSPC and CRPC patients by liquid biopsy. These findings confirmed the genomic diversity between CSPC patients and CRPC patients, which could guide the individualized and precise management of prostate cancer in general practice. Furthermore, our findings indicated that somatic alterations in AR, CDK12, BRCA2, ATM and TP53/RB1 might contribute to the development of CRPC.

Expanding armamentarium in advanced prostate cancer management: are all novel antiandrogens the same?

Prostate cancer (PCa) is the most common cancer in men. Androgen receptor axis plays a crucial role in the carcinogenesis of PCa. The mainstay treatment of prostate cancer is blockage of androgen receptor axis but in a vast majority of patient resistance to androgen deprivation therapy is inevitable. After using enzalutamide, the first new generation anti-androgen (AA), two new generation AA drugs were synthesized. New generation anti-androgen drugs are used especially in castration resistance prostate cancer. But recently, there are new publications regarding using new generation anti-androgens in castration sensitive prostate cancer patients. In this review, we will compare structure, mechanisms of effect and clinical outcomes in phase 3 trials of these new generation AA drugs.

Clinical efficacy of abiraterone and enzalutamide metastatic castration sensitive prostate cancer patients who progressed rapidly on docetaxel with a genomic analysis.

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.

Going towards a precise definition of the therapeutic management of de-novo metastatic castration sensitive prostate cancer patients: How prognostic classification impact treatment decisions

De-novo metastatic castration sensitive prostate cancer (mCSPC) is a subgroup of prostate cancer associated with poor prognosis. Recently, the treatment of mCSPC has been enriched by new life-prolonging options, including the combination of docetaxel or abiraterone acetate with androgen deprivation therapy (ADT). Of note, the advantage of chemohormonal therapy was more relevant in the subgroup of high-volume disease compared to low-volume, while the survival prolongation of abiraterone was observed only in high-risk patients. Choosing the most appropriate therapy is one of the most debated issues. This review describes the latest news on de-novo mCSPC to better outline patients' management. At the ESMO 2018 Congress two novel studies focused on this setting have been presented, trying to define the role of radiotherapy to the primary tumour and the efficacy of abiraterone acetate in the subset of low-risk patients. We have analysed these results in light of the evidence already available.

Prostate cancer and Cancer Treatment-Induced Bone Loss(CTIBL)

Osteopenia and osteoporosis often become the long term complications in cancer treatment and is defined as cancer treatment-induced bone loss(CTIBL). Hormonal therapy is the main factor for CTIBL in both men and women. Androgen deprivation therapy(ADT)is a mainstay in the systemic therapy for prostate cancer(PC)and often persists for a long term. ADT induces bone loss and increases the risk of osteoporosis and bone fractures, which reduces QOL of the patients, results in the need of nursing care state and a serious adverse event to be connected for shortening of the overall survival. It is important that we prevent a fracture above all in the bone management of patients with PC. According to the results of overseas large-scale clinical trials, denosumab is a drug having the highest evidence level. And it is necessary to set a clear treatment objective depending on the clinical condition of the PC patients, and to use it. In the non-bone metastatic, castration-sensitive PC patients, we do it with a dose for the purpose of the prevention of osteoporosis and bone fractures, and it is demanded what a dose for the purpose of prevention and in bone metastatic, castration resistant PC patients, the reduction of symptomatic skeletal events. However, There is no benefit in prolongation of overall survival by addition of denosumab or zoledronic acid. Care for oral hygiene should be considered to avoid osteonecrosis of the jaw, oral infection and hypocalcemia.

Association of NaF PET/CT findings with PSA and alkaline phosphatase in untreated castration-sensitive prostate cancer.

122 Background: NaF PET/CT is an emerging imaging technique with potentially high sensitivity in detecting bone metastasis (mets), however, its role in castration-‐sensitive prostate cancer (CSPC) is undefined and it remains unclear which CSPC patients should have NaF PET/CT. Methods: We retrospectively reviewed NaF PET/CT scans done on 45 patients with untreated, high risk CSPC with the goal of determining which disease features were associated with positive findings. Two blinded radiologists reviewed each scan and determined by consensus if findings were negative for metastasis (0% liklihood of mets), possible (50%), probable (75%), or consistent with mets (90%). Prostate specific antigen (PSA) and alkaline phosphatase (AP) values were then evaluated at time of NaF scan when available. Results: Of the 45 patients 2 were Gleason 6, 5 were Gleason 7, 36 were Gleason 8 to 10, 2 unknown. When grouped by findings on NaF PET/CT, there were no substantial differences seen between median PSA or AP values. When patients with both PSA and AP values > median were evaluated, there was no clear association with NaF PET/CT findings. Conclusions: Preliminary findings from this small retrospective analysis suggest that there may be limited associations between PSA and/or AP with findings on NaF PET/CT scan in untreated patients with CSPC. Further analysis in larger cohorts of pts is required. [Table: see text]