Current trends for the use of androgen deprivation therapy in conjunction with radiotherapy for patients with unfavorable intermediate-risk, high-risk, localized, and locally advanced prostate cancer

Efficacy of metformin drug in preventing metabolic syndrome associated with androgen deprivation therapy (ADT) in prostate cancer patients: A systematic review and meta-analysis

BACKGROUND

Prostate cancer patients undergoing long-term (Androgen deprivation therapy) ADT will tend to have metabolic changes. Metabolic syndrome represents the accumulation of several medical conditions that significantly increase the risk of developing severe diseases like cardiovascular disorders, insulin resistance, and hyperglycemia. We are conducting this systematic review and meta-analysis to fill up the gap and to resolve the debate regarding the effectiveness of metformin in reducing metabolic syndrome associated with ADT in prostate cancer patients.

METHODS

We conducted the systematic review and meta-analysis according to the Handbook of Cochrane Systematic Review of Intervention and the PRISMA guidelines. We conducted the search process using the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Scopus, and Web of Science. We selected the articles that fit within the following criteria, Randomized Controlled Trials (RCTs) and Cohort studies which evaluate the efficacy of metformin in reducing metabolic syndromes for prostate cancer patients undergoing androgen deprivation therapy (ADT). The efficacy of metformin in metabolic syndrome that resulted from using androgen deprivation therapy for prostate cancer patients was evaluated by the changes from baseline in Body Mass Index (BMI), waist circumference by cm, glycated hemoglobin (HbA1c), and blood pressure both systolic and diastolic. Revman software Version 5.4.1 was used to perform all statistical analyses.

RESULTS

Our search retrieved 781 records. Seven records were included in our study: 5 published randomized control clinical trials and 2 cohort studies and only 6 studies were included in the meta-analysis. For BMI the pooled effect estimates of 3 studies favored Metformin over placebo, but this is not a significant difference (MD = -0.9, P = 0.05), for systolic pressure the pooled effect estimates of 3 studies favored Metformin over placebo, but this is not a significantly different placebo (MD = -3.18, P = 0.22), for HBA1c the pooled effect estimates of 3 studies showed that no significant difference between placebo and metformin (MD = -0.01, P = 0.86)002E CONCLUSION: Despite the promising direction in some parameters, our findings underscore the need for further research to establish a clearer understanding of metformin's role in mitigating metabolic changes in prostate cancer patients undergoing ADT.

Pre-Exposure to Stress-Inducing Agents Increase the Anticancer Efficacy of Focused Ultrasound against Aggressive Prostate Cancer Cells

Despite the initial success in treatment of localized prostate cancer (PCa) using surgery, radiation or hormonal therapy, recurrence of aggressive tumors dictates morbidity and mortality. Focused ultrasound (FUS) is being tested as a targeted, noninvasive approach to eliminate the localized PCa foci, and strategies to enhance the anticancer potential of FUS have a high translational value. Since aggressive cancer cells utilize oxidative stress (Ox-stress) and endoplasmic reticulum stress (ER-stress) pathways for their survival and recurrence, we hypothesized that pre-treatment with drugs that disrupt stress-signaling pathways in tumor cells may increase FUS efficacy. Using four different PCa cell lines, i.e., LNCaP, C4-2B, 22Rv1 and DU145, we tested the in vitro effects of FUS, alone and in combination with two clinically tested drugs that increase Ox-stress (i.e., CDDO-me) or ER-stress (i.e., nelfinavir). As compared to standalone FUS, significant (p < 0.05) suppressions in both survival and recurrence of PCa cells were observed following pre-sensitization with low-dose CDDO-me (100 nM) and/or nelfinavir (2 µM). In drug pre-sensitized cells, significant anticancer effects were evident at a FUS intensity of as low as 0.7 kW/cm². This combined mechanochemical disruption (MCD) approach decreased cell proliferation, migration and clonogenic ability and increased apoptosis/necrosis and reactive oxygen species (ROS) production. Furthermore, although activated in cells that survived standalone FUS, pre-sensitization with CDDO-me and/or nelfinavir suppressed both total and activated (phosphorylated) NF-κB and Akt protein levels. Thus, a combined MCD therapy may be a safe and effective approach towards the targeted elimination of aggressive PCa cells.

Androgen deprivation therapy and side effects: are GnRH antagonists safer?

Androgen deprivation therapy (ADT) with gonadotropin-releasing hormone (GnRH) agonists and antagonists is the mainstay of advanced prostate cancer treatment. Both drug classes decrease levels of luteinizing hormone and follicle-stimulating hormones (FSH), thereby lowering testosterone to castrate levels. This is associated with adverse events (AEs), including cardiovascular (CV) disorders, bone fractures, metabolic dysfunction, and impaired cognitive function. This literature review discusses these AEs, with a focus on CV and bone-related events. A hypothesis-generating meta-analysis of six clinical trials showed a potentially increased risk for CV disorders with GnRH agonists versus the GnRH antagonist degarelix. While no study has directly compared GnRH agonists versus antagonists with a primary CV outcome, one hypothesis for this observation is that GnRH agonists lead to initial surges in FSH that may negatively impact CV health, whereas antagonists do not. GnRH agonists are associated with metabolic and cognitive AEs and while data are lacking for GnRH antagonists, no differences in risk are predicted. Other common AEs with ADT include injection site reactions, which are much more common with degarelix than with GnRH agonists, which may reflect differing administration and injection techniques. Future studies are needed to further evaluate and compare the safety profiles of GnRH agonists and antagonists, especially in patients with pre-existing CV disease and other co-morbidities. Physicians should carefully evaluate benefits and risks when prescribing ADT and ensure that side effects are well managed.

GPM6B Inhibit PCa Proliferation by Blocking Prostate Cancer Cell Serotonin Absorptive Capacity

Prostate cancer is currently one of the most common fatal tumor types in men. Although multiple treatments can alleviate some cases, advanced prostate cancer, especially CRPC, still has a very poor prognosis. Therefore, early detection and diagnosis of prostate cancer have a very important role in the prognosis of patients. Glycoprotein M6B (GPM6B) is a transmembrane protein that belongs to the proteolipid protein family. GPM6B has been proved and can be used as a biomarker for gynecological malignancies and breast carcinoma. However, there are no studies that explored the functions of GPM6B in PCa. We explored differentially expressed genes in prostate cancer by analyzing TCGA data and found GPM6B downregulated in PCa tissues compared to that in normal prostate tissues. The GPM6B expression in PCa patient's tumor tissues was significantly related to clinical stage, T classification, lymph node metastasis, and distant metastasis, but not significantly related to age and Gleason score. Also, patients with highGPM6B expression had a better prognosis. The overexpression of GPM6B in prostate cancer cells could inhibit cell proliferation. Serotonin treatment could enhance the proliferation of PCa cell lines; moreover, fluoxetine could reverse this result. In conclusion, we identified GPM6B as a tumor suppressor in PCa. In mechanism, it can regulate the uptaking of serotonin and inhibit the growth of prostate cancer. These results suggested the potential function of GPM6B as a diagnostic marker of PCa and provided clues for the development of new treatment targets for PCa.

Annexin A1 promotes the nuclear localization of the epidermal growth factor receptor in castration-resistant prostate cancer

Epidermal growth factor receptor is a cancer driver whose nuclear localization has been associated with the progression of prostate cancer to the castration-resistant phenotype. Previous reports indicated a functional interaction between this receptor and the protein Annexin A1, which has also been associated with aggressive tumors. The molecular pathogenesis of castration-resistant prostate cancer remains largely unresolved, and herein we have demonstrated the correlation between the expression levels and localization of the epidermal growth factor receptor and Annexin A1 in prostate cancer samples and cell lines. Interestingly, a higher expression of both proteins was detected in castration-resistant prostate cancer cell lines and the strongest correlation was seen at the nuclear level. We verified that Annexin A1 interacts with the epidermal growth factor receptor, and by using prostate cancer cell lines knocked down for Annexin A1, we succeeded in demonstrating that Annexin A1 promotes the nuclear localization of epidermal growth factor receptor. Finally, we showed that Annexin A1 activates an autocrine signaling in castration-resistant prostate cells through the formyl peptide receptor 1. The inhibition of such signaling by Cyclosporin H inhibits the nuclear localization of epidermal growth factor receptor and its downstream signaling. The present work sheds light on the functional interaction between nuclear epidermal growth factor receptor and nuclear Annexin A1 in castration-resistant prostate cancer. Therefore, strategies to inhibit the nuclear localization of epidermal growth factor receptor through the suppression of the Annexin A1 autocrine loop could represent an important intervention strategy for castration-resistant prostate cancer.

A Prospective Single-Arm Phase 2 Study of Stereotactic Magnetic Resonance Guided Adaptive Radiation Therapy for Prostate Cancer: Early Toxicity Results

PURPOSE

Use of stereotactic body radiation therapy (SBRT) is increasing in patients with localized prostate cancer, but concerns about early and late gastrointestinal (GI) and genitourinary (GU) toxicity exist after moderately or extremely hypofractionated radiation therapy schemes. Magnetic resonance guided radiation therapy (MRgRT) was clinically introduced in 2014. MrgRT allows for SBRT delivery with smaller uncertainty margins and permits daily adaptive planning. A phase 2 study in patients with localized prostate cancer was performed to study early GI and GU toxicity after SBRT using MRgRT.

METHODS AND MATERIALS

One hundred one patients with clinical stage T1-3bN0M0 prostate cancer were enrolled in this prospective phase 2 study. All but 4 patients had intermediate- or high-risk prostate cancer, and 82.2% received adjuvant hormonal treatment. MRgRT was delivered in 5 fractions of 7.25 Gy to the target volume using daily plan adaptation with simultaneous relative sparing of the urethra to a dose of 6.5 Gy per fraction. Early toxicity was studied using both clinician- (Common Terminology Criteria for Adverse Events and Radiation Therapy Oncology Group) and patient-reported outcome measurements (European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30, Quality of Life Questionnaire PR25, and International Prostate Symptom Scoring).

RESULTS

The maximum cumulative grade ≥2 early GU and GI toxicity measured by any symptom at any study time point was 23.8% and 5.0%, respectively. No early grade 3 GI toxicity was observed. Early grade 3 GU toxicity was 0% and 5.9% according to the Common Terminology Criteria for Adverse Events and Radiation Therapy Oncology Group and scoring systems, respectively, as a result of different grading of radiation cystitis. The low incidence of early GI toxicity was confirmed by patient-reported outcome data. GU grade ≥2 toxicity peaked to 19.8% at the end of MRgRT, followed by a return to the baseline average score at 3-month follow-up.

CONCLUSIONS

This prospective study of MRgRT in patients with localized prostate cancer observed a low incidence of early GI and GU toxicity, both in clinician- and patient-reported outcome measurements.

New Insights into the Role of Polybromo-1 in Prostate Cancer

The human protein Polybromo-1 (PBMR1/BAF180) is a component of the SWI/SNF chromatin-remodeling complex that has been reported to be deregulated in tumors. However, its role in prostate cancer (PCa) is largely unknown. In this study, we described the PBRM1 transcriptional levels and the protein expression/localization in tissues of PCa patients and in prostatic cell lines. Increased PBRM1 mRNA levels were found in PCa samples, when compared to benign disease, and were correlated with higher Gleason score. We also verified that only the nuclear localization of PBRM1 protein is correlated with a more aggressive disease and high Prostate-Specific Antigen (PSA) levels in tissue microarrays. Intriguing expression patterns of mRNA and protein were identified in the cell lines. Although PBRM1 protein was restricted to the nuclei, in tumor cell lines in non-neoplastic cells, it was also present in vesicular-like structures that were dispersed within the cytoplasm. We knocked-down PBRM1 in the castration-resistant PCa (CRPC) cell line PC-3 and we verified that PBRM1 promotes the expression of several markers of aggressiveness, including EpCAM, TGF-β, and N-Cadherin. Therefore, our data supported the hypothesis that PBRM1 displays a pivotal role in the promotion and maintenance of the malignant behavior of PCa, especially in CRPC.

Impact of androgen deprivation therapy on apparent diffusion coefficient and T2w MRI for histogram and texture analysis with respect to focal radiotherapy of prostate cancer

PURPOSE

Accurate prostate cancer (PCa) detection is essential for planning focal external beam radiotherapy (EBRT). While biparametric MRI (bpMRI) including T2-weighted (T2w) and diffusion-weighted images (DWI) is an accurate tool to localize PCa, its value is less clear in the case of additional androgen deprivation therapy (ADT). The aim of this study was to investigate the value of a textural feature (TF) approach on bpMRI analysis in prostate cancer patients with and without neoadjuvant ADT with respect to future dose-painting applications.

METHODS

28 PCa patients (54-80 years) with (n = 14) and without (n = 14) ADT who underwent bpMRI with T2w and DWI were analyzed retrospectively. Lesions, central gland (CG), and peripheral zone (PZ) were delineated by an experienced urogenital radiologist based on localized pre-therapeutic histopathology. Histogram parameters and 20 Haralick TF were calculated. Regional differences (i. e., tumor vs. PZ, tumor vs. CG) were analyzed for all imaging parameters. Receiver-operating characteristic (ROC) analysis was performed to measure diagnostic performance to distinguish PCa from benign prostate tissue and to identify the features with best discriminative power in both patient groups.

RESULTS

The obtained sensitivities were equivalent or superior when utilizing the TF in the no-ADT group, while specificity was higher for the histogram parameters. However, in the ADT group, TF outperformed the conventional histogram parameters in both specificity and sensitivity. Rule-in and rule-out criteria for ADT patients could exclusively be defined with the aid of TF.

CONCLUSIONS

The TF approach has the potential for quantitative image-assisted boost volume delineation in PCa patients even if they are undergoing neoadjuvant ADT.

Ligand-dependent EphA7 signaling inhibits prostate tumor growth and progression

The downregulation of receptor tyrosine kinase EphA7 is frequent in epithelial cancers and linked to tumor progression. However, the detailed mechanism of EphA7-mediated prostate tumor progression remains elusive. To test the role of EphA7 receptor in prostate cancer (PCa) progression directly, we generated EphA7 receptor variants that were either lacking the cytoplasmic domain or carrying a point mutation that inhibits its phosphorylation by site-directed mutagenesis. Overexpression of wild-type (WT) EphA7 in PCa cells resulted in decreased tumor volume and increased tumor apoptosis in primary tumors. In addition, ectopic expression of WT EphA7 both can delay PCa cell proliferation and could inhibit PCa cell migration and invasion. This protein can also induce PCa cell apoptosis that correlated with increasing the protein expression levels of Bax, elevating the caspase-3 activities, reducing the protein expression levels of Bcl-2 and facilitating the dephosphorylation of Akt, which is further increased by the stimulation of ephrinA5-Fc. However, expression of these EphA7 mutants in PCa cells has no effect in vivo and in vitro. The expression of EphA7 and ephrinA5 was significantly decreased in PCa specimens compared with BPH tissues or paired normal tissues. Moreover, the phosphorylation of EphA7 was positively related with ephrinA5 expression in human prostate tissues. In sum, receptor phosphorylation of EphA7, at least in part, suppress PCa tumor malignancy through targeting PI3K/Akt signaling pathways.

Comparative effectiveness of prostate cancer treatments for patient-centered outcomes: A systematic review and meta-analysis (PRISMA Compliant)

BACKGROUND

In the context of prostate cancer (PCa) characterized by the multiple alternative treatment strategies, comparative effectiveness analysis is essential for informed decision-making. We analyzed the comparative effectiveness of PCa treatments through systematic review and meta-analysis with a focus on outcomes that matter most to newly diagnosed localized PCa patients.

METHODS

We performed a systematic review of literature published in English from 1995 to October 2016. A search strategy was employed using terms "prostate cancer," "localized," "outcomes," "mortality," "health related quality of life," and "complications" to identify relevant randomized controlled trials (RCTs), prospective, and retrospective studies. For observational studies, only those adjusting for selection bias using propensity-score or instrumental-variables approaches were included. Multivariable adjusted hazard ratio was used to assess all-cause and disease-specific mortality. Funnel plots were used to assess the level of bias.

RESULTS

Our search strategy yielded 58 articles, of which 29 were RCTs, 6 were prospective studies, and 23 were retrospective studies. The studies provided moderate data for the patient-centered outcome of mortality. Radical prostatectomy demonstrated mortality benefit compared to watchful waiting (all-cause HR = 0.63 CI = 0.45, 0.87; disease-specific HR = 0.48 CI = 0.40, 0.58), and radiation therapy (all-cause HR = 0.65 CI = 0.57, 0.74; disease-specific HR = 0.51 CI = 0.40, 0.65). However, we had minimal comparative information about tradeoffs between and within treatment for other patient-centered outcomes in the short and long-term.

CONCLUSION

Lack of patient-centered outcomes in comparative effectiveness research in localized PCa is a major hurdle to informed and shared decision-making. More rigorous studies that can integrate patient-centered and intermediate outcomes in addition to mortality are needed.

Androgen receptor profiling predicts prostate cancer outcome

Prostate cancer is the second most prevalent malignancy in men. Biomarkers for outcome prediction are urgently needed, so that high-risk patients could be monitored more closely postoperatively. To identify prognostic markers and to determine causal players in prostate cancer progression, we assessed changes in chromatin state during tumor development and progression. Based on this, we assessed genomewide androgen receptor/chromatin binding and identified a distinct androgen receptor/chromatin binding profile between primary prostate cancers and tumors with an acquired resistance to therapy. These differential androgen receptor/chromatin interactions dictated expression of a distinct gene signature with strong prognostic potential. Further refinement of the signature provided us with a concise list of nine genes that hallmark prostate cancer outcome in multiple independent validation series. In this report, we identified a novel gene expression signature for prostate cancer outcome through generation of multilevel genomic data on chromatin accessibility and transcriptional regulation and integration with publically available transcriptomic and clinical datastreams. By combining existing technologies, we propose a novel pipeline for biomarker discovery that is easily implementable in other fields of oncology.

CyberKnife Stereotactic Ablative Radiotherapy as an Option of Treatment for Patients With Prostate Cancer Having Oligometastatic Lymph Nodes

The aim of this study was to evaluate the effectiveness of CyberKnife-based stereotactic ablative radiotherapy on prostate cancer lymph node metastases. Our material consisted of 18 patients with 31 metastatic lymph nodes irradiated between 2011 and 2014 using CyberKnife-based stereotactic ablative radiotherapy. Patients were irradiated using fraction dose varied from 6 to 15 Gy (median 10), to the total dose of 24 to 45 Gy (median 30). Irradiated lymph node size varied from 0.4 to 4.0 cm. In all, 9 patients had single lymph node metastasis and 9 patients had metastases of 2 to 4 lymph nodes. Prostate-specific antigen concentration before radiotherapy varied from 0.01 to 15.58 (mean 6.97; median 4.66). All patients at the time of radiotherapy and follow-up received androgen deprivation therapy. Mann-Whitney U, Kaplan-Meier method, and log-rank tests were used in statistical analysis. We obtained the following results: after CyberKnife stereotactic ablative radiotherapy, prostate-specific antigen concentration dropped in majority of cases and during the last control varied from 0.00 to 258.00 (median 2.5), and was lower in patients without dissemination to other organs ( P = .01). Complete regression was found in 12 lesions, stable disease in 13, and progression in 4. In 7 patients, the dissemination to other organs occurred. Our results allow us to conclude that CyberKnife stereotactic ablative radiotherapy of prostate cancer lymph node oligometastases gives good local control and relatively good prostate-specific antigen response.

Metabolic syndrome in prostate cancer: impact on risk and outcomes

Androgen-deprivation therapy (ADT) is a fundamental element of treatment for nonlocalized prostate cancer and for patients with high-risk disease who are not candidates for radical treatment. ADT has been linked to metabolic syndrome, which involves changes in metabolic factors. While distinct from classic metabolic syndrome, this type does include changes in body composition, lipid profiles and insulin resistance. The constellation of risk factors may be associated with cardiovascular morbidity and the onset of diabetes mellitus. Physicians should discuss in detail the risk and benefits of ADT, as well as any needed lifestyle modifications with patients before beginning therapy.

Acute Toxicity and Quality of Life in Patients With Prostate Cancer Treated With Protons or Carbon Ions in a Prospective Randomized Phase II Study--The IPI Trial

PURPOSE

The purpose of this study was to compare safety and feasibility of proton therapy with that of carbon ion therapy in hypofractionated raster-scanned irradiation of the prostate, in a prospective randomized phase 2 trial.

METHODS AND MATERIALS

In this trial, 92 patients with localized prostate cancer were enrolled. Patients were randomized to receive either proton therapy (arm A) or carbon ion therapy (arm B) and treated with a total dose of 66 Gy(relative biological effectiveness [RBE]) administered in 20 fractions (single dose of 3.3 Gy[RBE]). Patients were stratified by the use of antihormone therapy. Primary endpoint was the combined assessment of safety and feasibility. Secondary endpoints were specific toxicities, prostate-specific antigen progression-free survival (PFS), overall survival (OS), and quality of life (QoL).

RESULTS

Ninety-one patients completed therapy and have had a median follow-up of 22.3 months. Among acute genitourinary toxicities, grade 1 cystitis rates were 34.1% (39.1% in A; 28.9% in B) and 17.6% grade 2 (21.7% in A; 13.3% in B). Seven patients (8%) required urinary catheterization during treatment due to urinary retention, 5 of whom were in arm A. Regarding acute gastrointestinal toxicities, 2 patients treated with protons developed grade 3 rectal fistulas. Grade 1 radiation proctitis occurred in 12.1% (13.0% in A; 11.1% in B) and grade 2 in 5.5% (8.7% in A; 2.2% in B). No statistically significant differences in toxicity profiles between arms were found. Reduced QoL was evident mainly in fatigue, pain, and urinary symptoms during therapy and 6 weeks thereafter. All European Organization for Research and Treatment of Cancer QLQ-C30 and -PR25 scores improved during follow-up.

CONCLUSIONS

Hypofractionated irradiation using either carbon ions or protons results in comparable acute toxicities and QoL parameters. We found that hypofractionated particle irradiation is feasible and may be safe. Due to the occurrence of gel in the rectal wall and the consecutive occurrence of 2 rectal fistulas, we stopped using the insertion of spacer gel. Longer follow-up is necessary for evaluation of PFS and OS. (Ion Prostate Irradiation (IPI); NCT01641185; ClinicalTrials.gov.).

Risk of fracture in men with prostate cancer on androgen deprivation therapy: a population-based cohort study in New Zealand

BACKGROUND

Androgen deprivation therapy (ADT) administered as a prostate cancer treatment is known to exert multiple side effects including bone deterioration leading to bone fracture. The current analysis is to evaluate the burden of fracture risk in the New Zealand prostate cancer (PCa) population treated with ADT, and to understand the subsequent risk of mortality after a fracture.

METHODS

Using datasets created through linking records from the New Zealand Cancer Registry, National Minimal Dataset, Pharmaceutical Collection and Mortality Collection, we studied 25,544 men (aged ≥40 years) diagnosed with PCa between 2004 and 2012. ADT was categorised into the following groups: gonadotropin-releasing hormone (GnRH) agonists, anti-androgens, combined androgen blockade (GnRH agonists plus anti-androgens), bilateral orchiectomy, and bilateral orchiectomy plus pharmacologic ADT (anti-androgens and/or GnRH agonists).

RESULTS

Among patients receiving ADT, 10.8 % had a fracture compared to 3.2 % of those not receiving ADT (p < 0.0001). After controlling for age and ethnicity, the use of ADT was associated with a significantly increased risk of any fracture (OR = 2.83; 95 % CI 2.52-3.17) and of hip fracture requiring hospitalisation (OR = 1.82; 95 % CI 1.44-2.30). Those who received combined androgen blockade (OR = 3.48; 95 % CI 3.07-3.96) and bilateral orchiectomy with pharmacologic ADT (OR = 4.32; 95 % CI 3.34-5.58) had the greatest risk of fracture. The fracture risk following different types of ADT was confounded by pathologic fractures and spinal cord compression (SCC). ADT recipients with fractures had a 1.83-fold (95 % CI 1.68-1.99) higher mortality risk than those without a fracture. However, after the exclusion of pathologic fractures and SCC, there was no increased risk of mortality.

CONCLUSIONS

ADT was significantly associated with an increased risk of any fracture and hip fracture requiring hospitalisation. The excess risk was partly driven by pathologic fractures and SCC which are associated with decreased survival in ADT users. Identification of those at higher risk of fracture and close monitoring of bone health while on ADT is an important factor to consider. This may require monitoring of bone density and bone marker profiles.

Radiation therapy after radical prostatectomy: A single-centre radiation oncology experience in trends of referral and treatment practices

INTRODUCTION

Our objective was to assess whether referral and treatment practices have changed since publication of the Southwest Oncology Group (SWOG) 8794 Trial in 2009, the first randomized study to demonstrate an overall survival advantage of adjuvant radiation therapy (RT) after radical prostatectomy (RP).

METHODS

We retrospectively reviewed all medical charts of men who received RT at our institution between 2004 and 2014 following RP. All RT was conducted by a single radiation oncologist (DT). We divided the cohort into 2 groups according to first referral date before or after the SWOG 8794 trial publication (i.e., before 2010 and after 2010).

RESULTS

Medical charts were available for 161/165 patients (97.6%). RP was performed at the same institution in 58% of cases. The median time between surgery and first referral for RT decreased significantly from 672 days (interquartile range [IQR] 295-1449) before 2010 to 300 days (IQR 225-1023) after 2010 (p = 0.04). This trend was associated with lower median prostate-specific antigen (PSA) at RT referral (0.26 μg/L [IQR 0.17-0.48] vs. 0.46 μg/L [IQR 0.25-0.90], respectively; p = 0.001). Androgen-deprivation therapy with RT nearly tripled over time from 13% before 2010 to 37% after 2010 (p = 0.003). Throughout the study period, the time interval between surgery and RT initiation was positively correlated with pT-stage (p = 0.001), Gleason score (p = 0.005) and PSA doubling time (p < 0.001).

CONCLUSIONS

At our tertiary-referral academic institution, post-RP patients are notably referred earlier for RT and at lower PSA values compared to men treated prior to 2010. Further study is necessary to evaluate this impact on biochemical recurrence-free survival.

Hormonal therapy in oncology: a primer for the radiologist

OBJECTIVE

The purpose of this article is to provide a comprehensive imaging review of the common hormonal therapies used in oncology and the side effects associated with them.

CONCLUSION

Commonly used hormones in oncology include corticosteroids, somatostatin analogues, progestins, gonadotropin-releasing hormone agonists and antagonists, antiandrogens, aromatase inhibitors, and selective estrogen receptor modulators. Familiarity with these hormones and their side effects can help radiologists to be vigilant for the side effects and complications of these agents.

Differential post-prostatectomy cancer-specific survival of occult T3 vs. clinical T3 prostate cancer: Implications for managing patients upstaged on prostate magnetic resonance imaging

PURPOSE/OBJECTIVE

Long-term androgen deprivation therapy (ADT) was proven in randomized trials to be superior to short-term ADT for radiation-managed patients who have clinical T3 (cT3) disease, but it is unknown whether patients with T3 disease seen only on magnetic resonance imaging require similarly aggressive treatment. We attempted to study this issue by analogy by comparing the long-term post-prostatectomy survival of patients with cT3 disease versus cT1/T2 disease upstaged to pathologic T3 disease.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used to identify 60,165 men diagnosed with prostate adenocarcinoma between 1995 and 2002 who underwent prostatectomy. Prostate cancer-specific mortality (PCSM) was evaluated by stage after adjusting for grade, marital status, race, sex, year of diagnosis, and age.

RESULTS

The median follow-up was 10.5 years. Patients with cT1/T2 but pathologic T3a disease had significantly better 10-year PCSM than men with cT3 disease had (3.0% vs. 9.9%, adjusted hazard ratio [AHR] = 0.420, P<0.001), but they had worse PCSM than men with pathologic T2 disease had (3.0% vs. 0.91%, AHR = 2.53, P<0.001). Of patients with occult T3a disease, those with low-grade/intermediate-grade disease (Gleason score 7 or less) had a slightly higher 10-year PCSM when compared with those with pathologic T2 disease (1.34% vs. 0.91%, AHR = 1.69, P<0.001). Patients with cT1/T2 and pathologic T3b disease had similar PCSM as men presenting with cT3 disease (11.0% vs. 9.86%, AHR = 1.14 [0.862, 1.52], P = 0.353).

CONCLUSIONS

Patients with occult T3a disease had less than half the risk of PCSM as those with cT3 disease, and a subset of those men had similar risk as patients with pathologic T2 disease. Therefore, it is possible that radiation-managed patients with low-grade/intermediate-grade T3a disease by magnetic resonance imaging only might not require long-term ADT. However, patients with occult T3b or high-grade occult T3a disease have similar PCSM as that of those presenting with cT3 disease, so they should be treated as aggressively, including long-course ADT when managed by radiation.

Dose-Escalated Robotic SBRT for Stage I-II Prostate Cancer

Stereotactic body radiotherapy (SBRT) is the precise external delivery of very high-dose radiotherapy to targets in the body, with treatment completed in one to five fractions. SBRT should be an ideal approach for organ-confined prostate cancer because (I) dose-escalation should yield improved rates of cancer control; (II) the unique radiobiology of prostate cancer favors hypofractionation; and (III) the conformal nature of SBRT minimizes high-dose radiation delivery to immediately adjacent organs, potentially reducing complications. This approach is also more convenient for patients, and is cheaper than intensity-modulated radiotherapy (IMRT). Several external beam platforms are capable of delivering SBRT for early-stage prostate cancer, although most of the mature reported series have employed a robotic non-coplanar platform (i.e., CyberKnife). Several large studies report 5-year biochemical relapse rates which compare favorably to IMRT. Rates of late GU toxicity are similar to those seen with IMRT, and rates of late rectal toxicity may be less than with IMRT and low-dose rate brachytherapy. Patient-reported quality of life (QOL) outcomes appear similar to IMRT in the urinary domain. Bowel QOL may be less adversely affected by SBRT than with other radiation modalities. After 5 years of follow-up, SBRT delivered on a robotic platform is yielding outcomes at least as favorable as IMRT, and may be considered appropriate therapy for stage I–II prostate cancer.

Functional cyclic AMP response element in the breast cancer resistance protein (BCRP/ABCG2) promoter modulates epidermal growth factor receptor pathway- or androgen withdrawal-mediated BCRP/ABCG2 transcription in human cancer cells

Phosphorylated cyclic-AMP (cAMP) response element binding protein (p-CREB) is a downstream effector of a variety of important signaling pathways. We investigated whether the human BCRP promoter contains a functional cAMP response element (CRE). 8Br-cAMP, a cAMP analogue, increased the activity of a BCRP promoter reporter construct and BCRP mRNA in human carcinoma cells. Epidermal growth factor receptor (EGFR) pathway activation also led to an increase in p-CREB and in BCRP promoter reporter activity via two major downstream EGFR signaling pathways: the phosphotidylinositol-3-kinase (PI3K)/AKT pathway and the mitogen-activated protein kinase (MAPK) pathway. EGF treatment increased the phosphorylation of EGFR, AKT, ERK and CREB, while simultaneously enhancing BCRP mRNA and functional protein expression. EGF-stimulated CREB phosphorylation and BCRP induction were diminished by inhibition of EGFR, PI3K/AKT or RAS/MAPK signaling. CREB silencing using RNA interference reduced basal levels of BCRP mRNA and diminished the induction of BCRP by EGF. Chromatin immunoprecipitation assays confirmed that a putative CRE site on the BCRP promoter bound p-CREB by a point mutation of the CRE site abolished EGF-induced stimulation of BCRP promoter reporter activity. Furthermore, the CREB co-activator, cAMP-regulated transcriptional co-activator (CRTC2), is involved in CREB-mediated BCRP transcription: androgen depletion of LNCaP human prostate cancer cells increased both CREB phosphorylation and CRTC2 nuclear translocation, and enhanced BCRP expression. Silencing CREB or CRTC2 reduced basal BCRP expression and BCRP induction under androgen-depletion conditions. This novel CRE site plays a central role in mediating BCRP gene expression in several human cancer cell lines following activation of multiple cancer-relevant signaling pathways.

Annotating STEAP1 regulation in prostate cancer with 89Zr immuno-PET

Antibodies and antibody-drug conjugates targeting the cell surface protein 6 transmembrane epithelial antigen of prostate 1 (STEAP1) are in early clinical development for the treatment of castration-resistant prostate cancer (PCa). In general, antigen expression directly affects the bioactivity of therapeutic antibodies, and the biologic regulation of STEAP1 is unusually complicated in PCa. Paradoxically, STEAP1 can be induced or repressed by the androgen receptor (AR) in different human PCa models, while also expressed in AR-null PCa. Consequently, there is an urgent need to translate diagnostic strategies to establish which regulatory mechanism predominates in patients to situate the appropriate therapy within standard of care therapies inhibiting AR.

METHODS

To this end, we prepared and evaluated (89)Zr-labeled MSTP2109A ((89)Zr-2109A), a radiotracer for PET derived from a fully humanized monoclonal antibody to STEAP1 in preclinical PCa models.

RESULTS

(89)Zr-2109A specifically localized to the STEAP1-positive human PCa models CWR22Pc, 22Rv1, and PC3. Moreover, (89)Zr-2109A sensitively measured treatment-induced changes (∼66% decline) in STEAP1 expression in CWR22PC in vitro and in vivo, a model we showed to express STEAP1 in an AR-dependent manner.

CONCLUSION

These findings highlight the ability of immuno-PET with (89)Zr-2109A to detect acute changes in STEAP1 expression and argue for an expansion of ongoing efforts to image PCa patients with (89)Zr-2109A to maximize the clinical benefit associated with antibodies or antibody-drug conjugates to STEAP1.

Sexual bother in men with advanced prostate cancer undergoing androgen deprivation therapy

INTRODUCTION

Men with advanced prostate cancer (APC) undergoing androgen deprivation therapy (ADT) often experience distressing sexual side effects. Sexual bother is an important component of adjustment. Factors associated with increased bother are not well understood.

AIMS

This study sought to describe sexual dysfunction and bother in APC patients undergoing ADT, identify socio-demographic and health/disease-related characteristics related to sexual bother, and evaluate associations between sexual bother and psychosocial well-being and quality of life (QOL).

METHODS

Baseline data of a larger psychosocial intervention study was used. Pearson's correlation and independent samples t-test tested bivariate relations. Multivariate regression analysis evaluated relations between sexual bother and psychosocial and QOL outcomes.

MAIN OUTCOME MEASURES

The Expanded Prostate Cancer Index Composite sexual function and bother subscales, Center for Epidemiologic Studies Depression Scale, Functional Assessment of Cancer Therapy--General, and Dyadic Adjustment Scale were the main outcome measures.

RESULTS

Participants (N = 80) were 70 years old (standard deviation [SD] = 9.6) and reported 18.7 months (SD = 17.3) of ADT. Sexual dysfunction (mean = 10.1; SD = 18.0) was highly prevalent. Greater sexual bother (lower scores) was related to younger age (β = 0.25, P = 0.03) and fewer months of ADT (β = 0.22, P = 0.05). Controlling for age, months of ADT, current and precancer sexual function, sexual bother correlated with more depressive symptoms (β = -0.24, P  = 0.06) and lower QOL (β = 0.25, P = 0.05). Contrary to hypotheses, greater sexual bother was related to greater dyadic satisfaction (β = -0.35, P = 0.03) and cohesion (β = -0.42, P = 0.01).

CONCLUSIONS

The majority of APC patients undergoing ADT will experience sexual dysfunction, but there is variability in their degree of sexual bother. Psychosocial aspects of sexual functioning should be considered when evaluating men's adjustment to ADT effects. Assessment of sexual bother may help identify men at risk for more general distress and lowered QOL. Psychosocial interventions targeting sexual bother may complement medical treatments for sexual dysfunction and be clinically relevant, particularly for younger men and those first starting ADT.

Use of regulators and inhibitors of Pim-1, a serine/threonine kinase, for tumour therapy (review)

Pim-1 is a proto-oncogene that encodes a serine/threonine kinase that is overexpressed in a range of haematopoietic malignancies and solid cancers. Pim-1 expression is tightly regulated by multiple biomolecules at different levels. Several lines of evidence have indicated that dysregulation of Pim-1 can interfere with the cell cycle and apoptosis to promote malignant transformation of a number of types of tumour. Thus, investigation of Pim-1 regulation may provide important theoretical guidance for the development of molecular targeting therapies and drug treatments for Pim-1‑associated diseases. Regulators of Pim-1 expression, include microRNAs, oestrogen, inecalcitol, adenosine triphosphate (ATP) mimetic inhibitors and ATP competitive inhibitors of Pim-1. Combinations of inhibitors of Pim-1 expression and Pim-1‑specific inhibitors may provide novel therapies for cancer patients and directions for cancer treatment.