Comprehensive treatment for metastatic castration-resistant prostate cancer with neuroendocrine differentiation:a case report

Retrospective analysis of the progression of a case of metastatic castration-resistant prostate cancer with neuroendocrine differentiation:the patient was a 65 year old man with prostate adenocarcinoma on prostate biopsy,Gleason 4+4 score=8,70%,ISUP4 group,localized invasion of nerves.Progressed to metastatic castration-resistant prostate cancer after 8 months of novel endocrine therapy,persistent elevated PSA after endocrine therapy,chemotherapy,and radiation,abdominal metastasis,brain metastasis,gastric metastasis,and staging as neuroendocrine differentiation after second prostate biopsy,which is a highly malignant subtype and has been concerned as a mechanism of resistance to targeted therapies.We discuss how to choose a more optimal treatment plan and outline the patient's diagnostic and therapeutic course.We provide a reflection for the clinical study of metastatic castration-resistant prostate cancer with neuroendocrine type.

Future Directions in Metastatic Castration Resistant Prostate Cancer (mCRPC): Clinical Rationale and Use of New-Generation Hormonal Therapies

Several recent studies in mCRPC have identified the mechanisms of tumoral growth after the disease becomes unresponsive to standard hormonal therapy. These studies have highlighted the importance of residual intratumoral androgens in maintaining androgen receptor (AR) transcriptional activity in mCRPC [1]. Based on this findings, it has been possible to develop drugs, blocking the key enzyme in the biosynthesis of androgens through the inhibition of cytochrome p450 17 (CYP17) such as Abiraterone Acetate (AA) and drugs which directly target the AR including Enzalutamide (E) and Orteronel. Before this new knowledge, mCRPC treatment benefited from chemotherapy with taxanes. Recently a new taxane, Cabazitaxel (C), was approved in second line setting in association with prednisone. Retrospective analyses have tried to clarify the current role of chemotherapy in mCRPC patients and the right chemotherapy sequence of use of chemotherapy compared to new hormonal agents. Moreover, it would be important to address changes in the endpoints used in clinical trials, based on the stage of disease including the presence tumor-related symptoms, in order to identify the right therapeutic strategy.

Prognostic factors in Chinese patients with metastatic castration-resistant prostate cancer treated with docetaxel-based chemotherapy

This study aims to evaluate the potential value of patient characteristics in predicting overall survival （OS） in patients with metastatic castration-resistant prostate cancer （mCRPC） treated with docetaxel-based thermotherapy. A total of 115 patients with mCRPC undergoing a docetaxel q3w regimen were enrolled in this study. A survival analysis was performed using the Kaplan-Meier method. Cox proportional hazards models were used to evaluate the prognostic value of all covariates for OS. OS was also analysed after stratifying patients according to the results of multivariate analysis. The median OS for the entire cohort was 17.0 months. The multivariate analysis showed that the prostate-specific antigen doubling time （PSADT）, baseline haemoglobin （Hb） concentration, alkaline phosphatase （ALP） concentration, cycles of chemotherapy and time to castration resistance were independent prognostic factors of OS. According to the presence of PSADT 〈46.3 days and baseline ALP/〉 110 IU 1-1, all patients were divided into three risk groups： low-risk group （no risk factors）, intermediate-risk group （one risk factor） and high-risk group （two risk factors）. Median OSs for patients in low-, intermediate- and high-risk groups were 28.0 months （95% Ch 23.8-32.2）, 21.0 months （95% Ch 18.9-23.1） and 11.0 months （95% Ch 7.6-14.4）, respectively （P〈O.O01）. In conclusion, PSADT, baseline Hb concentration, ALP concentration, cycles of chemotherapy and time to castration resistance were independent prognostic factors of OS in Chinese patients with mCRPC treated with docetaxel. PSADT combined with the baseline ALP concentration could be a useful risk stratification parameter for evaluating survival outcomes.

Current paradigms and evolving concepts in metastatic castration-resistant prostate cancer

Until recently, docetaxel-based therapy represented the only therapy shown to prolong survival in patients with metastatic castration-resistant prostate cancer （mCRPC）. The past year and a half has been marked by unprecedented progress in treatments for this disease. Three positive phase III clinical trials have emerged, each evaluating agents （sipuleuceI-T, cabazitaxel and abiraterone） with distinct mechanisms of action. Herein, the three pivotal trials are described alongside both past and current large phase III studies conducted in this mCRPC. The overall survival for patients with mCRPC treated in current clinical trials is considerably longer than noted in the past. We note that more recent trials with older agents have also shown improved survival and discuss potential non-therapeutic biases that influence this critical measure of outcome. The necessity for utilizing randomized trials when evaluating new therapeutics is emphasized given the changing prognosis in this mCRPC.

Prostate Cancer, Castration-Resistant Prostate Cancer (CRPC), Radium-223 Dichloride Injection for Bone Metastasized Prostate Cancer

Purpose: The purpose of this paper is to discuss the most important facts about prostate cancer, its treatments and efficacy, the type of prostate cancer that does not improve with hormonal therapy (Castration-Resistant Prostate Cancer-CRPC), and the recently approved Radium-223 dichloride targeted therapy for CRPC that has metastasized to bones. Prostate cancer is the third most common malignancy diagnosed worldwide and the most common malignant disease in men. Also, the incidence of prostate cancer varies between regions. So it’s important to have a proper understanding of all above points to prevent the further development and spread of cancer and improve the cure rate. Design: The paper begins by discussing what prostate cancer is, the risk factors, clinical manifestations, and the treatments for prostate cancer. It covers the clinical manifestations, pathology, screening (cancer biomarker Prostate Specific Antigen, Digital Rectal Examination—DRE, prostate biopsy, and imaging) and treatments for prostate cancer. The paper then delves into the main treatment methods for prostate cancer, including how Castration-Resistant Prostate Cancer (CRPC) differs from normal prostate cancer after hormone suppression therapy. Additionally, it discusses the effectiveness of the recently introduced Radium-223 dichloride injection as a radiation-targeted therapy for treating CRPC that has metastasized to bones. This section covers the properties of radium-223 dichloride injection, its pharmacokinetics, pharmacodynamics, absorption and volume of distribution, half-life, metabolism, route of elimination, clearance, toxicity, adverse effects, and mechanism of action at the tumor site. It also discusses preclinical studies related to radium-223 dichloride injection and its effectiveness in treating CRPC patients with bone metastasis. Conclusion: Prostate cancer is a common cancer that can be treated with surgery or hormonal therapy. However, if the cancer progresses despite hormonal therapy, Radium-223 dichloride injection can be used as a radiation target therapy to treat patients with CRPC and symptomatic bone metastases. This treatment kills tumor cells in bones and reduces associated pain with minimal damage to surrounding normal tissue. However, the metastatic disease cannot be cured and can only offer palliation for the patient. Suggestions: Based on the facts, Radium-223 target therapy is effective in treating and providing palliation for cancers. It is suggested to further develop the usage of radiation target therapy and to test the safety and efficacy of more than 6 injections of Radium-223 dichloride and its combination with currently used chemotherapy drugs for bone metastasized CRPC. This paper aims to contribute to future research designs related to cancer therapies using radiation and to design new studies and practical implementations, especially regarding the usage of radium-223 dichloride.

Radium-223 in metastatic castration resistant prostate cancer

In 2004, docetaxel was approved for the treatment of metastatic castration-resistant prostate cancer （mCRPC）. For the next several years, there was a lull in drug approvals. However, from 2010 onwards, 5 additional therapies have been approved on the basis of showing a survival benefit in phase III studies. These agents include sipuleuceI-T, cabazitaxel, abiraterone, enzalutamide and （most recently） radium-223. Amongst radiopharmaceuticals currently used for advanced prostate cancer （e.g. samarium-153 and strontium-89）, radium-223 possesses several unique properties. As an alpha-emitting compound, the agent produces a high-energy output over a short range, facilitating selective destruction of tissue within the bone in the region of osteoblastic lesions while sparing surrounding normal tissue. The current review will outline biological rationale for radium-223 and also provide an overview of preclinical and clinical development of the agent. Rational sequencing of radium-223 and combinations, in the increasingly complex landscape of mCRPC will be discussed, along with factors influencing clinical implementation.

Radium-223 and metastatic castration-resistant prostate cancer: All that glitters is not gold

After being approved by the National Drug Agency in several countries, Radium-223 (Ra-223) is gaining wide acceptance in the treatment of bone metastatic castration resistant prostate cancer. The exact mechanism of action remain unclear: The established model of direct alpha-particle irradiation from the remodelling bone surface, where Ra-223 accumulates, surrounding the tumor foci can explain a lethal effect only on metastatic microdeposits, but not on higher tumor burden. According to the “pre-metastatic niche model”, it is likely that Ra-223 targets several non-tumoral cell types of the tumor microenvironment involved in the complex mechanism of cancer bone homing and colonization. A deeper insight into this hypothetical mechanism will lead to a more accurate dosimetric approach and to find optimal sequencing and/or combination with the other therapeutic options.

The effectiveness of the TAX 327 nomogram in predicting overall survival in Chinese patients with metastatic castration-resistant prostate cancer

Based on the results of TAX 327, a nomogram was developed to predict the overall survival of metastatic castration-resistant prostate cancer （mCRPC） after first-line chemotherapy. The nomogram, however, has not been validated in an independent dataset, especially in a series out of clinical trials. Thus, the objective of the current study was to validate the TAX 327 nomogram in a community setting in China. A total of 146 patients with mCRPC who received first-line chemotherapy （docetaxel or mitoxantrone） were identified. Because clinical trials are limited in China's Mainland, those patients did not receive investigational treatment after the failure of first-line chemotherapy. The predicted overall survival rate was calculated from the TAX 327 nomogram. The validity of the model was assessed with discrimination, calibration and decision curve analysis. The median survival of the cohort was 21 months （docetaxel） and 19 months （mitoxantrone） at last follow-up. The predictive c-index of the TAX 327 nomogram was 0.66 （95% CI： 0.54-0.70）. The calibration plot demonstrated that the 2-year survival rate was underestimated by the nomogram. Decision curve analysis showed a net benefit of the nomogram at a threshold probability greater than 30%. In conclusion, the present validation study did not confirm the predictive value of the TAX 327 nomogram in a contemporary community series of men in China, and further studies with a large sample size to develop or validate nomograms for predicting survival and selecting therapies in advanced prostate cancer are necessary.

The prognostic factors of effective ketoconazole treatment for metastatic castration-resistant prostate cancer： who can benefit from ketoconazole therapy？

We investigated the prognostic value of some variables of effective ketoconazole treatment for metastatic castration-resistant prostate cancer （mCRPC）. In total, 163 patients with mCRPC were eligible, receiving ketoconazole 200-400 mg three times daily with replacement doses of prednisone. Progression-free survival （PFS） was calculated from the beginning of the ketoconazole therapy to the onset of disease progression. The prognostic value of different variables for PFS was assessed by Cox regression analysis. The median PFS was 2.6 months （0.5-8.6 months） for these patients. The serum testosterone level changed during therapy, which decreased when the prostate-specific antigen （PSA） declined; the serum testosterone level increased as the levels of PSA relapsed. The median PFS values for patients associated with different factors were the following： 1.4 and 3.5 months for a nadir PSA of ≥ 0.2 and 〈0.2 ng ml- 1, respectively （hazard rate （HR）=4.767, P〈0.001）; 3.1 and 1.6 months for a baseline testosterone of ≥0.1 and 〈0.1 ng m1-1, respectively （HR=2.865, P=0.012）; 2.8 and 1.9 months for a baseline haemoglobin of ≥ 120 and 〈120 g 1-1, respectively （HR= 1.605, P〈0.001）; and 3.0 and 1.9 months for a PSA doubling time （PSADT） of ≥ 2.0 and 〈2.0 months, respectively （HR= 1.454, P=-0.017）. A risk model was constructed according to the four factors that divided patients into three subgroups of low risk （0-1 factors）, moderate risk （2 factors） and high risk （3-4 factors） with PFS values of 3.6, 3.0 and 1.4 months, respectively （HR=1.619, P〈0.001）. A nadir PSA of ≥0.2 ng m1-1, a baseline testosterone of 〈0.1 ng m1-1, a baseline haemoglobin of 〈 120 g I- 1 and a PSADT of 〈2 months were associated with a poor PFS. This risk model could provide evidence to predict the survival benefit of ketoconazole therapy.

End points of clinical trials in metastatic castration-resistant prostate cancer:A systematic review

AIM： To review the defnition and performance of the commonly used end points in trials of systemic thera-pies in metastatic castration-resistant prostate cancer patients. METHODS： A literature search was undertaken on PubMed database to identify studies meeting estab-lished criteria, with the aim of selecting randomized clinical trials and study definition and performance of their end points. The end points were grouped into three categories： overall survival （OS）, time-to-event end points, and response end points. A special analysis was performed for secondary end points of the studies which documented a beneft in OS in the experimental arm. Finally, publishes analyses for surrogacy of the in-cluded end points were also reported. RESULTS： OS, time-to-event and response end points in 31 selected trials were analyzed. OS was the pri-mary end point in 14 trials, and the secondary end point in 17. A time-to-event end point was the primaryend point in 8 studies, and the secondary end point in 22; the most reported time-to-event end points were composite end points, and the events changed among trials. A response end point was the primary end point in 9 studies, in 3 it was prostate-specifc antigen （PSA）-related, in 3 pain-related and in 3 mixed. A response end point was the secondary end point in 19 studies： PSA response and radiologic response were the most frequently used secondary end points in 19 and 11 tri-als, respectively, while pain response was used in 5 studies.CONCLUSION： A homogeneous defnition of progres-sion in future trials is mandatory. Among response end points, pain-response and PSA-response appear to be the most reliable.

Castrate Resistant Metastatic Prostate Cancer: Options for a Patient in 2012

Castrate resistant metastatic prostate cancer remains a fatal disease. Through preclinical studies and clinical trials, a multitude of options have been made available to prolong the life of these patients, as well as improve quality of life. First line treatment options following tumor progression after androgen deprivation therapy include Provenge and docetaxel. Several options are available as second line treatment, including cabazitaxel, abiraterone, and enzalutamide. Many drugs currently being studied are very promising, such as alpharadin. Here we review treatment options for patients suffering from disease progression after androgen deprivation therapy, and offer a review of the current available options for the clinician.

Adaptive pathways and emerging strategies overcoming treatment resistance in castration resistant prostate cancer

The therapies available for prostate cancer patients whom progress from hormonesensitive to castration resistant prostate cancer include both systemic drugs,including docetaxel and cabazitaxel,and drugs that inhibit androgen signaling such as enzalutamide and abiraterone.Unfortunately,it is estimated that up to 30%of patients have primary resistance to these treatments and over time even those who initially respond to therapy will eventually develop resistance and their disease will continue to progress regardless of the presence of the drug.Determining the mechanisms involved in the development of resistance to these therapies has been the area of intense study and several adaptive pathways have been uncovered.Androgen receptor(AR)mutations,expression of AR-V7(or other constitutively active androgen receptor variants),intracrine androgen production and overexpression of androgen synthesis enzymes such as Aldo-Keto Reductase Family 1,Member C3(AKR1C3)are among the many mechanisms associated with resistance to anti-androgens.In regards to the taxanes,one of the key contributors to drug resistance is increased drug efflux through ATP Binding Cassette Subfamily B Member 1(ABCB1).Targeting these resistance mechanisms using different strategies has led to various levels of success in overcoming resistance to current therapies.For instance,targeting AR-V7 with niclosamide or AKR1C3 with indomethacin can improve enzalutamide and abiraterone treatment.ABCB1 transport activity can be inhibited by the dietary constituent apigenin and antiandrogens such as bicalutamide which in turn improves response to docetaxel.A more thorough understanding of how drug resistance develops will lead to improved treatment strategies.This review will cover the current knowledge of resistance mechanisms to castration resistant prostate cancer therapies and methods that have been identified which may improve treatment response.

Androgen synthesis inhibitors in the treatment of castration-resistant prostate cancer

Suppression of gonadal testosterone synthesis represents the standard first line therapy for treatment of metastatic prostate cancer. However, in the majority of patients who develop castration-resistant prostate cancer （CRPC）, it is possible to detect persistent activation of the androgen receptor （AR） through androgens produced in the adrenal gland or within the tumor itself. Abiraterone acetate was developed as an irreversible inhibitor of the dual functional cytochrome P450 enzyme CYP17 with activity as a 17（^-hydroxylase and 17,20-1yase. CYP17 is necessary for production of nongonadal androgens from cholesterol. Regulatory approval of abiraterone in 2011, based on a phase III trial showing a significant improvement in overall survival （OS） with abiraterone and prednisone versus prednisone, represented proof of principle that targeting AR is essential for improving outcomes in men with CRPC. Inhibition of 17α-hydroxylase by abiraterone results in accumulation of upstream mineralocorticoids due to loss of cortisol-mediated suppression of pituitary adrenocorticotropic hormone （ACTH）, providing a rationale for development of CYP17 inhibitors with increased specificity for 17,20-1yase （orteronel, galeterone and VT-464） that can potentially be administered without exogenous corticosteroids. In this article, we review the development of abiraterone and other CYP17 inhibitors; recent studies with abiraterone that inform our understanding of clinical parameters such as drug effects on quality-of-life, potential early predictors of response, and optimal sequencing of abiraterone with respect to other agents; and results of translational studies providing insights into resistance mechanisms to CYP17 inhibitors leading to clinical trials with drug combinations designed to prolong abiraterone benefit or restore abiraterone activity.

Maximal androgen blockade versus castration alone in patients with metastatic prostate cancer

Maximum androgen blockade （MAB）, consisting of an antiandrogen plus either a luteinizing hormone- releasing hormone agonist （LHRHA） or orchiectomy, is a standard care for patients with prostate cancer. Although, clinical trial results have been equivocal, none has shown a significant advantage in favor of MAB over castration alone in metastatic prostate cancer and MAB has been the subject of considerable controversy. The aim of this study was to compare MAB （orchiectomy or LHRHA＂Goserelin＂） and anti-androgen ＂Bicalutamide＂ with castration alone （orchiectomy or LHRHA） in previ- ously untreated metastatic prostate cancer patients. Methods： Hundred eligible patients with adequate performance status and adequate hematologic, hepatic and renal functions were included. MAB arm, fifty patients underwent castration either surgically by orchiectomy or medically by receiving Goserelin （3.6 rag） depot, which was injected subcutaneously every 28 days plus bicalutamide 50 mg once daily. Castration alone arm, fifty patients underwent castration alone either surgically by orchiectomy or medically by receiving Goserelin （3.6 mg） depot. Results： During the period from January 2011 to January 2013, with a median follow up of 18 months （range 6 to 24 months）, there were eight deaths （16%）, in MAB arm and ten deaths （20%） in castration alone arm. At three months, there were 35 patients （70%） with prostate specific antigen （PSA） normalization （-〈 4 mg/dL） in MAB arm versus 17 patients （34%） with PSA normalization in castration alone arm （P = 0.001）. The median progression free survival （PFS） times were 22.18 months （95% CI, 19.7 to 24.2 months） for MAB arm versus 22 months in castration alone arm （95% CI, 18 to 25.9 months; P = 0.045）. The survival rates for MAB arm were 82% at 18 months and 70.6% at 24 months versus 78.7% at 18 months and 75.1% at 24 months in castration alone arm （P 〉 0.05）. The median overall survival （OS） was not reached in either arm. Both hematological and non-hematological toxicities were com- parable in both arms. Conclusion： MAB significantly improves the PSA normalization rate at 12 weeks and PFS compared to castration alone with no significant difference in overall survival and with comparable acceptable toxicities. However further studies are needed to document such findings.

New developments in the treatment of castration resistant prostate cancer

In the past 5 years, the treatment and understanding of metastatic castrate resistant prostate cancer （CRPC） have improved dramatically. Our understanding of the mechanisms of castration resistance has allowed for the development of new drugs to target prostate cancer, and our understanding of genetic mutations may give us new tools with which to more accurately diagnose and be able to predict the course of this heterogeneous disease. This article summarizes the recent advances in the understanding of the development of CRPC, as well as the new drugs and targets, which have evolved from this basic research.

IL13Rα1 prevents a castration resistant phenotype of prostate cancer by targeting hexokinase 2 for ubiquitin-mediated degradation

Objective:Androgen deprivation therapy(ADT)is still the principal treatment option for prostate cancer(PCa).In addition to reactivation of androgen receptor signaling,the resistance of PCa to apoptosis during ADT also contributes to castration resistant PCa(CRPC).A previous study reported that gene transfer of IL-13Rα2 into PCa cells sensitized the cells to the IL-13R-targeted cytotoxin IL13Rα1,leading to apoptosis.Compared with IL-13Rα2,IL13Rα1 is more constitutively expressed in PCa cells,but its function in PCa remains to be established.Methods:We determined the role and expression of IL13Rα1 in PCa cancer cells using western blotting,flow cytometry,and cell proliferation assays.Co-immunoprecipitation and mass spectrometry were used to identify the proteins that interacted with IL13Rα1,to elucidate its function.Results:In this study,we showed that IL13Rα1 was selectively suppressed in androgen-deprived PCa cells and that its suppression tended to be associated with poor prognoses of PCa patients.IL13Rα1 overexpression promoted apoptosis and inhibited tumor growth under androgen-deprived or castrated conditions(P<0.01).Mechanistically,IL13Rα1 recruited and facilitated ubiquitin protein ligase E3C-mediated ubiquitination and degradation of hexokinase 2(HK2),resulting in glycolytic inhibition and eventually leading to PCa cell apoptosis.Furthermore,our data revealed that mutated ataxia-telangiectasia kinase phosphorylated and facilitated the selective ubiquitin proteasome-mediated degradation of HK2.Notably,IL13Rα1-overexpressing PCa cells were more susceptible to apoptosis and exhibited reduced tumor growth after exposure to the HK2 inhibitor,2-deoxy-D-glucose(P<0.01).Conclusions:Our data identified a tumor suppressor role for IL13Rα1 in preventing the resistance of PCa cells to apoptosis during androgen deprivation by inhibiting glycolysis.IL13Rα1-mediated signaling involving HK2 may therefore provide a novel treatment target and strategy for CRPC.

Real-world evaluation of upfront docetaxel in metastatic castrationsensitive prostate cancer

BACKGROUND The majority of patients with newly diagnosed metastatic prostate cancer(PC)initially respond to androgen deprivation therapy(ADT)and are classified as metastatic castration-sensitive PC(mCSPC).Following months to years of ADT,the disease tends to become resistant to ADT.Recent randomized phase-III trials demonstrated a survival benefit with the addition of upfront docetaxel to ADT in mCSPC.Following its implementation in routine care,this combined treatment strategy requires more detailed evaluation in a real-world setting.AIM To assess the real-world outcome and safety of upfront docetaxel treatment in mCSPC.METHODS A multicenter retrospective cohort study in the Southeast Health Care Region of Sweden was performed.This region includes approximately 1.1 million citizens and the oncology departments of Linköping,Jönköping,and Kalmar.All patients given upfront docetaxel for mCSPC from July 2015 until December 2017 were included.The primary endpoint was progression-free survival(PFS)at 12 mo,and the secondary endpoints were PFS at 24 mo,overall survival(OS),treatment intensity,adverse events,and unplanned hospitalizations.Exploratory analyses on potential prognostic parameters were performed.RESULTS Ninety-four patients were eligible and formed the study cohort.PFS at 12 and 24 mo was 75%(95%CI:66–84)and 58%(46–70),respectively.OS at 12 and 24 mo was 93%(87–99)and 86%(76–96).A total of 91%of patients(n=86)were given docetaxel according to the standard protocol of 75 mg/m2 every 3 wk(6 cycles),while 9%(n=8)received a modified protocol of 50 mg/m2 every 2 wk(9 cycles).The average overall dose intensity for those commencing standard treatment was 91%.Univariate Cox regression analyses show that baseline PSA>180 vs<180 and the presence of distant metastases vs locoregional lymph node metastases were only negative prognostic factors(HR 2.86,95%CI:1.39–5.87,P=0.0041 and 3.36,95%CI:1.03–10.96,P=0.045).Following multivariate analysis,statistical significance remained for PSA(2.51,95%CI:1.21–5.19,P=0.013)but not for metastatic status(2.60,95%CI:0.78–8.65,P=0.12).Febrile neutropenia was recorded in 21%(n=20)of patients,and 26%(n=24)had at least one episode of unplanned hospitalization under and up to 30 d after the treatment course.CONCLUSION Results from this study support the implementation of upfront docetaxel plus ADT as part of the standard of care treatment strategy in mCSPC.

Radiotherapy of Oligoprogressive Lesions in Castration-Resistant Prostate Cancer: Impact on Second-Generation Hormone Therapy

Background: The therapeutic standard for oligoprogressive prostate cancer resistant to castration is second-generation hormone therapy. This systemic treatment is expensive. There are oligoprogressive lesions accessible to radiotherapy. Objectives: To study the impact of radiotherapy of oligoprogressive lesions on the implementation of second generation hormone therapy. Patients and Methods: A retrospective study from 2012 to 2020 was carried out. All patients with oligoprogressive prostate cancer who had received radiotherapy on one or more lesions in progression were collated. Survival was calculated using the Kaplan-Meier method. Results: 8 patients were treated with stereotactic and conformational radiotherapy between August 2012 and August 2020 in the context of oligoprogressive prostate cancer resistant to castration. The median age at diagnosis of oligoprogression was 73 years with a median PSA level of 3.11 ng/ml. Nine lesions were diagnosed with PET scan PSMA. All the lesions were treated by radiotherapy with different regimens. After a median follow-up of 12.5 months, 7 patients showed a biochemical response to treatment with a median decrease in PSA of 67%. The median survival without clinical or biochemical progression was 7 months. The median survival without the need for further systemic treatment was 9 months. During the follow-up period, six patients received second-generation hormone therapy to treat their relapse, and the other two showed no clinical or biochemical relapse. Conclusion: Radiotherapy may be an alternative to delay the introduction of difficult-to-access second-generation hormone therapy in developing countries. A prospective study could validate this therapeutic approach.

Treatment-induced neuroendocrine prostate cancer and de novo neuroendocrine prostate cancer:Identification,prognosis and survival,genetic and epigenetic factors

Neuroendocrine prostate cancer(NEPC)shows an aggressive behavior compared to prostate cancer(PCa),also known as prostate adenocarcinoma.Scanty foci in PCa can harbor genetic alternation that can arise in a heterogeneity of prostate cancer.NEPC may arise de novo or develop following androgen deprivation therapy(ADT).NEPC that arise following ADT has the nomenclature“treatmentemerging/induced NEPC(t-NEPC)”.t-NEPC would be anticipated in castration resistant prostate cancer(CRPC)and metastatic PCa.t-NEPC is characterized by low or absent androgen receptor(AR)expression,independence of AR signaling,and gain of neuroendocrine phenotype.t-NEPC is an aggressive metastatic tumor,develops from PCa in response to drug induced ADT,and shows very short response to conventional therapy.t-NEPC occurs in 10%-17%of patients with CRPC.De novo NEPC is rare and is accounting for less than 2%of all PCa.The molecular mechanisms underlying the trans-differentiation from CRPC to t-NEPC are not fully elucidated.Sphingosine kinase 1 plays a significant role in t-NEPC development.Although neuroendocrine markers:Synaptophysin,chromogranin A,and insulinoma associated protein 1(INSM1)are expressed in t-NEPC,they are non-specific for diagnosis,prognosis,and follow-up of therapy.t-NEPC shows enriched genomic alteration in tumor protein P53(TP53)and retinoblastoma 1(RB1).There are evidences suggest that t-NEPC might develop through epigenetic evolution.There are genomic,epigenetic,and transcriptional alterations that are reported to be involved in development of t-NEPC.Knock-outs of TP53 and RB1 were found to contribute in development of t-NEPC.PCa is resistant to immunotherapy,and at present there are running trials to approach immunotherapy for PCa,CRPC,and t-NEPC.

Mismatch repair enzyme expression in primary and castrate resistant prostate cancer

Objective:Although the utility of immunohistochemistry(IHC)for assessing mismatch repair(MMR)protein expression has been demonstrated in solid tumors including primary prostate cancer(PCa),its utility has not been assessed in castration-resistant PCa(CRPC).Methods:Tissue microarrays were constructed from 127 radical prostatectomies and 155 CRPC metastases from 50 patients.MMR(MLH1,MSH2,MSH6,and PMS2)expression was assessed by IHC and gene expression arrays.Associations between MMR protein expression in PCa and CRPC and biochemical recurrence(BCR)or time from diagnosis to death respectively were determined.Results:There was no correlation between levels of MMR protein and BCR.Absence of MSH2 and MSH6 was the most pronounced at 15%and 22%in PCa and 17.8%and 16%in CRPC patients,respectively.MSH2 and MSH6 protein were absent in 9.4%and 8%of PCa and CRPC respectively.Absence of individual MMR proteins did not correlate with BCR or time from diagnosis to death.However absent MSH2/MSH6 in CRPC was associated with shorter time to death(pZ0.0006).Loss of MSH2 was verified at the gene expression level.This finding correlated with microsatellite instability previously reported in this CRPC cohort.