EAU guidelines on prostate cancer. Part II: Treatment of advanced, relapsing, and castration-resistant prostate cancer

Developing a model for forecasting Gleason score ≥7 in potential prostate cancer patients to reduce unnecessary prostate biopsies

PURPOSE

The diagnosis of Gleason score (GS) ≥7 with distinction from GS < 7 remains a difficult problem instructing clinical decisions. Moreover, the present wide application of prostate biopsy to increase prostate cancer detection rate might cause unnecessary and excessive examination or treatment. Therefore, a risk assessment model for forecasting GS ≥ 7 in potential prostate cancer patients was established to reduce unnecessary prostate biopsies.

METHODS

Patients (n = 981; September 2009 to January 2013) who underwent trans-rectal ultrasound (TRUS)-guided core prostate biopsy were retrospectively evaluated in the first stage of the study. Age, prostate-specific antigen (PSA), free PSA (fPSA), the free/total PSA ratio (f/t), prostate volume (PV), PSA density (PSAD), digital rectal examination (DRE) findings (texture, nodules) and B-ultrasound detection results (normal or abnormal, presence of hypoechoic mass or microcalcification) were considered as potential predictive factors. After multiple logistic regression analysis, independent variables used to build a nomogram were selected using a backward elimination selection procedure. Then, a model to forecast GS ≥ 7 was designed for potential prostate cancer patients. In the second stage of the study, 410 cases (January 2013 to March 2015) were subsequently evaluated using our model for prostate biopsies, and the outcomes of biopsies were compared between the two stages.

RESULTS

PSA, DRE texture, DRE nodules and B-ultrasound results were finally brought into our nomogram; a obviously greater area under the receiver operating characteristic (ROC) curve was obtained for the model than utilizing PSA, fPSA or PSAD alone (0.831 vs. 0.803, 0.770, 0.780 separately). We thereafter sought the best cutoff value in the ROC curve at 0.87, which provided sensitivity as high as 90%. Meanwhile, the specificity was 45.8%, which was much higher than the specificity of PSA, fPSA and PSAD at the same sensitivity level (37.7, 24.6 and 35.2%, respectively). In the first stage, the detection rate of GS ≥ 7 in the high-risk group was significantly higher than in the low-risk group (80.3 vs. 35.0%, p < 0.001). Furthermore, in the second stage, with the application of the new model associated with our former models, the rate of GS ≥ 7 was improved from 71.0 (697/981) to 79.2% (267/337) (p = 0.003).

CONCLUSIONS

The model for forecasting GS ≥ 7 is effective, which could reduce unnecessary prostate biopsies without delaying patients' diagnoses and treatments.

Salvage radiotherapy in prostate cancer patients. Planning, treatment response and prognosis using (11)C-choline PET/CT

OBJECTIVE

To assess the prognostic value of the therapeutic response by (11)C-choline PET/CT in prostate cancer patients with biochemical recurrence in which (11)C-choline PET/CT indicated radio-guided radiotherapy.

METHODS

The study included 37 patients initially treated with prostatectomy, who were treated due to biochemical recurrence. (11)C-choline PE/CT detected infra-diaphragmatic lymph-node involvement. All were selected for intensity modulated radiation therapy, escalating the dose according to the PET findings. One year after treatment patients underwent PSA and (11)C-choline PET/CT categorizing response (complete/partial/progression). Clinical/biochemical/image monitoring was performed until appearance of second relapse or 36 months in disease-free patients.

RESULTS

(11)C-choline PET/CT could detect lymph nodes in all 37 patients. They were 18 (48.6%) of more than a centimetre in size and 19 (51.3%) with no pathological CT morphology: 9 (24.3%) with positive lymph nodes of around one centimetre and 10 (27.0%) only less than a centimetre in size. The response by (11)C-choline PET/CT was categorised one year after radiotherapy: 16 patients (43.2%) complete response; 15 (40.5%) partial response, and 6 (16.2%) progression. The response was concordant between the PSA result and (11)C-choline PET/CT in 32 patients (86.5%), and discordant in five (13.5%). New recurrence was detected in 12 patients (80%) with partial response, and 5 (31.2%) with complete response. The mean time to recurrence was 9 months after partial response, and 18 months after complete response (significant difference, p<.0001).

CONCLUSION

(11)C-choline PET/CT allows the selection of patients with recurrent prostate cancer candidates for radiotherapy and to plan the technique. The evaluation of therapeutic response by (11)C-choline PET/CT has prognostic significance.

The Potential of MicroRNAs as Prostate Cancer Biomarkers

CONTEXT

Short noncoding RNAs known as microRNAs (miRNAs) control protein expression through the degradation of RNA or the inhibition of protein translation. The miRNAs influence a wide range of biologic processes and are often deregulated in cancer. This family of small RNAs constitutes potentially valuable markers for the diagnosis, prognosis, and therapeutic choices in prostate cancer (PCa) patients, as well as potential drugs (miRNA mimics) or drug targets (anti-miRNAs) in PCa management.

OBJECTIVE

To review the currently available data on miRNAs as biomarkers in PCa and as possible tools for early detection and prognosis.

EVIDENCE ACQUISITION

A systematic review was performed searching the PubMed database for articles in English using a combination of the following terms: microRNA, miRNA, cancer, prostate cancer, miRNA profiling, diagnosis, prognosis, therapy response, and predictive marker.

EVIDENCE SYNTHESIS

We summarize the existing literature regarding the profiling of miRNA in PCa detection, prognosis, and response to therapy. The articles were reviewed with the main goal of finding a common recommendation that could be translated from bench to bedside in future clinical practice.

CONCLUSIONS

The miRNAs are important regulators of biologic processes in PCa progression. A common expression profile characterizing each tumor subtype and stage has still not been identified for PCa, probably due to molecular heterogeneity as well as differences in study design and patient selection. Large-scale studies that should provide additional important information are still missing. Further studies, based on common clinical parameters and guidelines, are necessary to validate the translational potential of miRNAs in PCa clinical management. Such common signatures are promising in the field and emerge as potential biomarkers.

PATIENT SUMMARY

The literature shows that microRNAs hold potential as novel biomarkers that could aid prostate cancer management, but additional studies with larger patient cohorts and common guidelines are necessary before clinical implementation.

[(18)F]Choline PET/CT and stereotactic body radiotherapy on treatment decision making of oligometastatic prostate cancer patients: preliminary results

BACKGROUND

A new entity of patients with recurrent prostate cancer limited to a small number of active metastatic lesions is having growing interest: the oligometastatic patients. Patients with oligometastatic disease could eventually be managed by treating all the active lesions with local therapy, i.e. either surgery or ablative stereotactic body radiotherapy. This study aims to assess the impact of [(18)F]Choline ([(18)F]FMCH) PET/CT and the use stereotactic body radiotherapy (SBRT) in patients (pts) with oligometastatic prostate cancer (PCa).

METHODS

Twenty-nine pts with oligometastatic PCa (≤3 synchronous active lesions detected with [(18)F]FMCHPET/CT) were treated with repeated salvage SBRT until disease progression (development of > three active synchronous metastases). Primary endpoint was systemic therapy-free survival measured from the baseline [(18)F]FMCHPET/CT.

RESULTS

A total of 45 lesions were treated with SBRT. After a median follow-up of 11.5 months (range 3-40 months), 20 pts were still in the study and did not receive any systemic therapy. Nine pts started systemic therapy, and the median time of the primary endpoint was 39.7 months (CI 12.20-62.14 months). No grade 3 or 4 toxicity was recorded.

CONCLUSIONS

Repeated salvage [(18)F]FMCHPET/CT-guided SBRT is well tolerated and could defer the beginning of systemic therapy in selected patients with oligometastatic PCa.

Neural Cell Adhesion Protein CNTN1 Promotes the Metastatic Progression of Prostate Cancer

Prostate cancer metastasis is the main cause of disease-related mortality. Elucidating the mechanisms underlying prostate cancer metastasis is critical for effective therapeutic intervention. In this study, we performed gene-expression profiling of prostate cancer stem-like cells (PCSC) derived from DU145 human prostate cancer cells to identify factors involved in metastatic progression. Our studies revealed contactin 1 (CNTN1), a neural cell adhesion protein, to be a prostate cancer-promoting factor. CNTN1 knockdown reduced PCSC-mediated tumor initiation, whereas CNTN1 overexpression enhanced prostate cancer cell invasion in vitro and promoted xenograft tumor formation and lung metastasis in vivo. In addition, CNTN1 overexpression in DU145 cells and corresponding xenograft tumors resulted in elevated AKT activation and reduced E-cadherin (CDH1) expression. CNTN1 expression was not readily detected in normal prostate glands, but was clearly evident on prostate cancer cells in primary tumors and lymph node and bone metastases. Tumors from 637 patients expressing CNTN1 were associated with prostate cancer progression and worse biochemical recurrence-free survival following radical prostatectomy (P < 0.05). Collectively, our findings demonstrate that CNTN1 promotes prostate cancer progression and metastasis, prompting further investigation into the mechanisms that enable neural proteins to become aberrantly expressed in non-neural malignancies.

Surgical castration efficiently delays the time of starting a systemic chemotherapy in castration-resistant prostate cancer patients refractory to initial androgen-deprivation therapy

Background

The aim of this study was to investigate the effects of surgical castration, particularly delaying the time to entrance of systemic chemotherapy, in castration-resistant prostate cancer (CRPC) patients who were refractory to initial combination androgen deprivation therapy.

Materials and methods

We analyzed the clinical data of 14 CRPC patients diagnosed at Seoul National University Bundang Hospital (SNUBH) from November 2008 through May 2015. After exclusion of three patients, we finally analyzed the baseline characteristics of 11 CRPC patients. We also assessed the delaying time of docetaxel administration, which was defined as response duration, after surgical castration.

Results

After bilateral orchiectomy, the treatment response rate was 45.4% and the median duration of response was 9 months (range 4–48 mo). Responders had less aggressive biopsy Gleason scores compared to nonresponders. Notably, responders showed the reducing pattern of serum prostate specific antigen levels, while nonresponders demonstrated increasing tendency after surgical castration. Moreover, responders also presented with a reduction pattern of serum testosterone levels, whereas nonresponders showed an increasing pattern of testosterone levels after bilateral orchiectomy.

Conclusions

In summary, despite the limited number of cases for convincing evidence, our results shed light again on the clinical benefits of surgical castration prior to the systemic chemotherapy in some CRPC patients after initial hormone therapy.

Assessment of a new point-of-care system for detection of prostate specific antigen

Background

Measurement of the prostate specific antigen (PSA) remains an important tool in prostate cancer (PC) diagnosis. Due to limited availability of laboratory devices in an outpatient setting, compact and easy-to-handle point-of-care (POC) systems are desirable. Recently, a chip for PSA measurement on the concile® Ω100 POC reader platform was introduced. To investigate the clinical applicability, we evaluated the system in a consecutive cohort of patients undergoing PSA measurement in our outpatient clinic.

Methods

Between 07/2014 and 01/2015, PSA was analyzed in a total of 198 patients by the POC reader system and in parallel by an Immulite 2000® and Centaur® standard laboratory system, respectively. By standard (Immulite®) measurement, 67 (34,2 %) had PSA > 4 ng/ml and 131 (65,8 %) had PSA ≤ 4 ng/ml. Results were correlated by linear regression analyses for all patients and within PSA subgroups. For patients with available prostate histology after PSA measurement (n = 68), receiver-operating characteristic curves were created and area under the curve (AUC), sensitivity and specificity for the prediction of PC at best cut-off value were calculated.

Results

The coefficients of determination (r²) for the POC device compared to laboratory testing were 0.72 (Immulite®) and 0.63 (Centaur®), respectively (both p < 0.0001). In the PSA range of ≤4 ng/ml, the observed correlations were 0.75 and 0.70, respectively. For the POC test system, AUC for detection of PC was calculated with 0.745 while the standard laboratory tests showed 0.778 (Immulite®) and 0.771 (Centaur®). At best cut-off of 3.64 ng/ml, PSA analysis by the POC system showed a sensitivity of 85.7 % and a specificity of 66.7 %.

Conclusions

The POC system obtained good concordance to elaborate laboratory measurement. In a screening scenario, the system provides quick and reliable PSA measurement, especially in the PSA range up to 4 ng/ml.

Trends in prostate cancer in elderly in Denmark, 1980-2012

BACKGOUND

The purpose of the study is to elucidate the epidemiology of elderly patients with prostate cancer in Denmark and identify the differences between younger (<70 years) and elderly (≥70 years) patients.

MATERIAL AND METHODS

Prostate cancer was defined as ICD-10 code C61. Data were derived from the NORDCAN database with comparable data on cancer incidence, mortality, prevalence and relative survival in the Nordic countries, where the Danish data are delivered from the Danish Cancer Registry and the Danish Cause of Death Registry.

RESULTS

The average annual number of newly diagnosed prostate cancers in Denmark has risen from 1297 patients in 1980 to 4315 patients in 2012. The prevalence increased consistently in all age groups more than seven-fold in the period, from 3987 patients in 1980 to 28 951 patients in 2012. The cancer-specific mortality in Denmark has slightly increased over the observed period, in coherence with the growth of the population, resulting in unchanged mortality rates, with the exception of the patients above 80 years, where the mortality rates are increased. The one- and five-year relative survival for prostate cancer improved significantly for all age groups over the time period from 1980 to 2012.

CONCLUSION

The incidence, prevalence, and survival of elderly prostate cancer patients has increased over the observed period but with unchanged mortality rates, except in patients above 80 years, where the mortality rates were increasing.

Efficacy and safety of enzalutamide versus bicalutamide for patients with metastatic prostate cancer (TERRAIN): a randomised, double-blind, phase 2 study

BACKGROUND

Enzalutamide is an oral androgen-receptor inhibitor that has been shown to improve survival in two placebo-controlled phase 3 trials, and is approved for patients with metastatic castration-resistant prostate cancer. The objective of the TERRAIN study was to compare the efficacy and safety of enzalutamide with bicalutamide in patients with metastatic castration-resistant prostate cancer.

METHODS

TERRAIN was a double-blind, randomised phase 2 study, that recruited asymptomatic or minimally symptomatic men with prostate cancer progression on androgen-deprivation therapy (ADT) from academic, community, and private health-care provision sites across North America and Europe. Eligible patients were randomly assigned (1:1) via an interactive voice response system to receive enzalutamide 160 mg/day or bicalutamide 50 mg/day, both taken orally, in addition to ADT, until disease progression. Patients were stratified by a permutated block method (block size of four), by whether bilateral orchiectomy or receipt of luteinising hormone-releasing hormone agonist or antagonist therapy started before or after the diagnosis of metastases, and by study site. Participants, investigators, and those assessing outcomes were masked to group assignment. The primary endpoint was progression-free survival, analysed in all randomised patients. Safety outcomes were analysed in all patients who received at least one dose of study drug. The open-label period of the trial is in progress, wherein patients still on treatment at the end of the double-blind treatment period were offered open-label enzalutamide at the discretion of the patient and study investigator. This trial is registered with ClinicalTrials.gov, number NCT01288911.

FINDINGS

Between March 22, 2011, and July 11, 2013, 375 patients were randomly assigned, 184 to enzalutamide and 191 to bicalutamide. 126 (68%) and 168 (88%) patients, respectively, discontinued their assigned treatment before study end, mainly due to progressive disease. Median follow-up time was 20·0 months (IQR 15·0-25·6) in the enzalutamide group and 16·7 months (10·2-21·9) in the bicalutamide group. Patients in the enzalutamide group had significantly improved median progression-free survival (15·7 months [95% CI 11·5-19·4]) compared with patients in the bicalutamide group (5·8 months [4·8-8·1]; hazard ratio 0·44 [95% CI 0·34-0·57]; p<0·0001). Of the most common adverse events, those occurring more frequently with enzalutamide than with bicalutamide were fatigue (51 [28%] of 183 patients in the enzalutamide group vs 38 [20%] of 189 in the bicalutamide group), back pain (35 [19%] vs 34 [18%]), and hot flush (27 [15%] vs 21 [11%]); those occurring more frequently with bicalutamide were nausea (26 [14%] vs 33 [17%]), constipation (23 [13%] vs 25 [13%]), and arthralgia (18 [10%] vs 30 [16%]). The most common grade 3 or worse adverse events in the enzalutamide or bicalutamide treatment groups, respectively, were hypertension (13 [7%] vs eight [4%]), hydronephrosis (three [2%] vs seven [4%]), back pain (five [3%] vs three [2%]), pathological fracture (five [3%] vs two [1%]), dyspnoea (four [2%] vs one [1%]), bone pain (one [1%] vs four [2%]), congestive cardiac failure (four [2%] vs two [1%]), myocardial infarction (five [3%] vs none), and anaemia (four [2%] vs none]). Serious adverse events were reported by 57 (31%) of 183 patients and 44 (23%) of 189 patients in the enzalutamide and bicalutamide groups, respectively. One of the nine deaths in the enzalutamide group was thought to be possibly related to treatment (due to systemic inflammatory response syndrome) compared with none of the three deaths in the bicalutamide group.

INTERPRETATION

The data from the TERRAIN trial support the use of enzalutamide rather than bicalutamide in patients with asymptomatic or mildly symptomatic metastatic castration-resistant prostate cancer.

FUNDING

Astellas Pharma, Inc and Medivation, Inc.

Predictors of early androgen deprivation treatment failure in prostate cancer with bone metastases

Approximately 15% of men with hormone naïve metastatic prostate cancer primarily fail to respond to androgen deprivation treatment (ADT). The reason why the response to ADT differs in this subgroup of men with prostate cancer remains unclear. The aim of this study was to describe the characteristics of these men and to thereby define predictors of early ADT failure in prostate cancer patients with bone metastases. The study was based on 915 men from the prospective randomized multicenter trial (no. 5) conducted by the Scandinavian Prostate Cancer Group comparing parenteral estrogen with total androgen blockade. Early ADT failure was defined as death from metastatic prostate cancer within 12 months after the start of ADT. Multivariate logistic regression models were applied to identify clinical predictors of early ADT failure. Ninety‐four (10.3%) men were primarily nonresponders to ADT. Independent predictors of early ADT failure were poor Eastern Cooperative Oncology Group performance status (PS), analgesic consumption, low hemoglobin, and high Soloway score (extent of disease observed on the scan), in where patients with poor PS and/or high analgesic consumption had a threefold risk of early ADT failure. Not significantly factors related to early ADT failure were age, treatment, cardiovascular comorbidity, T category, grade of malignancy, serum estrogen level, and SHBG at enrolment. We analyzed characteristics of a subgroup of patients who primarily failed to respond to ADT. Four independent clinical predictors of early ADT failure could be defined, and men exhibiting these features should be considered for an alternative treatment.

Evaluation of PSMA PET/CT imaging using a 68Ga-HBED-CC ligand in patients with prostate cancer and the value of early pelvic imaging

PURPOSE

The aim of the study was to evaluate the diagnostic value of the prostate-specific membrane antigen (PSMA) ligand (68)Ga-HBED-CC (PSMA PET/CT) in patients with prostate cancer and evaluate the value of early imaging of the pelvis.

MATERIALS AND METHODS

The files of 28 patients were retrospectively evaluated. All patients had a histopatological confirmation of prostate cancer. PSMA PET/CT images were obtained at 5 and 60 min after injection from all patients.

RESULTS

Intense pathologic radiotracer uptake was observed in 23 patients (77%) at the site of primary tumour. Lymph node metastases were detected in 10 patients (36%) and bone metastases were detected in seven patients (25%). Bone scan (n=25) results revealed metastatic bone lesions in four patients, equivocal results in nine patients and normal results in 12 patients. PSMA PET/CT confirmed bone metastases in all four patients. Pathologic radiotracer uptake in PSMA PET/CT scans was observed only in one patient among those who had equivocal bone scans. PSMA PET/CT showed additional bone lesions in two patients who had a normal bone scan. When we compared early and late pelvic images we found no difference in the number of lesions detected. The maximum standardized uptake value (SUV(max)) for primary tumour, lymph nodes and bone metastases was significantly higher in late images.

CONCLUSION

PSMA PET/CT imaging seems to be a valuable imaging modality for evaluation of primary prostate cancer and it seems to have potential for the detection of lymph node and bone metastases. Early images 5 min p.i. can help to better distinguish between urinary bladder (before tracer accumulation occurs) and tumour lesions.

Periprostatic adipocytes act as a driving force for prostate cancer progression in obesity

Obesity favours the occurrence of locally disseminated prostate cancer in the periprostatic adipose tissue (PPAT) surrounding the prostate gland. Here we show that adipocytes from PPAT support the directed migration of prostate cancer cells and that this event is strongly promoted by obesity. This process is dependent on the secretion of the chemokine CCL7 by adipocytes, which diffuses from PPAT to the peripheral zone of the prostate, stimulating the migration of CCR3 expressing tumour cells. In obesity, higher secretion of CCL7 by adipocytes facilitates extraprostatic extension. The observed increase in migration associated with obesity is totally abrogated when the CCR3/CCL7 axis is inhibited. In human prostate cancer tumours, expression of the CCR3 receptor is associated with the occurrence of aggressive disease with extended local dissemination and a higher risk of biochemical recurrence, highlighting the potential benefit of CCR3 antagonists in the treatment of prostate cancer.

The Role of Positron Emission Tomography With (68)Gallium (Ga)-Labeled Prostate-specific Membrane Antigen (PSMA) in the Management of Patients With Organ-confined and Locally Advanced Prostate Cancer Prior to Radical Treatment and After Radical Prostatectomy

The role of positron emission tomography (PET) with (68)Gallium (Ga)-labeled prostate-specific membrane antigen (PSMA) imaging for prostate cancer is gaining prominence. Current imaging strategies, despite having progressed significantly, have limitations, in particular their ability to diagnose metastatic lymph node involvement. Preliminary results of PET with (68)Ga-labeled PSMA have shown encouraging results, particularly in the recurrent prostate cancer setting. Furthermore, the ability of PET with (68)Ga-labeled PSMA of playing a dual diagnostic and therapeutic setting (theranostics) is currently being investigated as well. PET with (68)Ga-labeled PSMA certainly has a role to play in bridging some of the voids in contemporary prostate cancer imaging tools.

(18)F-fluoride positron emission tomography/computed tomography and bone scintigraphy for diagnosis of bone metastases in newly diagnosed, high-risk prostate cancer patients: study protocol for a multicentre, diagnostic test accuracy study

BACKGROUND

For decades, planar bone scintigraphy has been the standard practice for detection of bone metastases in prostate cancer and has been endorsed by recent oncology/urology guidelines. It is a sensitive method with modest specificity. (18)F-fluoride positron emission tomography/computed tomography has shown improved sensitivity and specificity over bone scintigraphy, but because of methodological issues such as retrospective design and verification bias, the existing level of evidence with (18)F-fluoride positron emission tomography/computed tomography is limited. The primary objective is to compare the diagnostic properties of (18)F-fluoride positron emission tomography/computed tomography versus bone scintigraphy on an individual patient basis.

METHODS/DESIGN

One hundred forty consecutive, high-risk prostate cancer patients will be recruited from several hospitals in Denmark. Sample size was calculated using Hayen's method for diagnostic comparative studies. This study will be conducted in accordance with recommendations of standards for reporting diagnostic accuracy studies. Eligibility criteria comprise the following: 1) biopsy-proven prostate cancer, 2) PSA ≥ 50 ng/ml (equals a prevalence of bone metastasis of ≈ 50% in the study population on bone scintigraphy), 3) patients must be eligible for androgen deprivation therapy, 4) no current or prior cancer (within the past 5 years), 5) ability to comply with imaging procedures, and 6) patients must not receive any investigational drugs. Planar bone scintigraphy and (18)F-fluoride positron emission tomography/computed tomography will be performed within a window of 14 days at baseline. All scans will be repeated after 26 weeks of androgen deprivation therapy, and response of individual lesions will be used for diagnostic classification of the lesions on baseline imaging among responding patients. A response is defined as PSA normalisation or ≥ 80% reduction compared with baseline levels, testosterone below castration levels, no skeletal related events, and no clinical signs of progression. Images are read by blinded nuclear medicine physicians. The protocol is currently recruiting.

DISCUSSION

To the best of our knowledge, this is one of the largest prospective studies comparing (18)F-fluoride positron emission tomography/computed tomography and bone scintigraphy. It is conducted in full accordance with recommendations for diagnostic accuracy trials. It is intended to provide valid documentation for the use of (18)F-fluoride positron emission tomography/computed tomography for examination of bone metastasis in the staging of prostate cancer.

[Cytoreductive radical prostatectomy for prostate cancer with minimal osseous metastases: results of a first feasibility and case control study]

BACKGROUND

Androgen deprivation therapy (ADT) represents the standard treatment for patients with prostate cancer (PCA) and osseous metastases. We explored the role of cytoreductive radical prostatectomy in PCA with low volume skeletal metastases in terms of a feasibility study.

MATERIAL AND METHODS

A total of 23 patients with biopsy proven PCA, minimal osseous metastases (≤3 hot spots on bone scan), absence of visceral or extensive lymph node metastases and a decrease in prostate-specific antigen (PSA) to <1.0 ng/ml after neoadjuvant ADT were included in the feasibility study (group A). The control group (group B) consisted of 38 men with metastatic PCA who were treated by ADT alone. Surgery-related complications, time to castration resistance, symptom-free, cancer-specific and overall survival were analyzed using descriptive statistical analyses.

RESULTS

The mean age was 61 years (range 42-69 years) and 64 years (47-83) in groups A and B, respectively, with similar patient characteristics in terms of initial PSA level, biopsy Gleason score, clinical stage and extent of metastatic disease. The median follow-up was 34.5 months (7-75 months) and 47 months (28-96 months) in groups A and B, respectively. Median time to castration resistance was 40 months (9-65 months) and 29 months (16-59 months) in groups A and B, respectively (p=0.04). Patients in group A experienced significantly better clinical symptom-free (38.6 versus 26.5 months, p=0.032) and cancer-specific survival rates (95.6% versus 84.2%, p=0.043) whereas the overall survival was similar. In group A none of the men underwent palliative surgical procedures for locally progressing PCA compared to 29% in group B.

CONCLUSIONS

Cytoreductive radical prostatectomy is feasible in well-selected men with metastatic PCA who responded well to neoadjuvant ADT. These men have a long life expectancy and the risk of locally recurrent PCA and local complications are reduced. Cytoreductive radical prostatectomy might be a treatment option in the multimodal management of PCA with minimal osseous metastases.

External Validation of the Cancer of the Prostate Risk Assessment Postsurgical Score for Prediction of Disease Recurrence after Radical Prostatectomy

Objective. The cancer of the prostate risk assessment (CAPRA-S) postsurgical score predicts recurrence, metastasis, and cancer-specific survival after radical prostatectomy (RP). We evaluated the relation between CAPRA-S score and biochemical recurrence (BCR) in prostate cancer after RP in our clinic. Materials and Methods. This study was performed on 203 patients with prostate carcinoma who underwent open RP and regional lymph node dissection in our clinic between 2008 and 2013. We calculated the CAPRA-S scores including prostate-specific antigen (PSA) at diagnosis, pathology Gleason score, surgical margin, seminal vesicle invasion, extracapsular extension, and lymph node involvement. The patients were divided into 3 risk groups (low, intermediate, and high risk) according to risk scores. Results. Recurrence occurred in 17.8% of the patients (36 patients out of 203 patients) with a median of 11.7-month follow-up. The average recurrence-free survival time is 44.6 months. Surgical margin invasion and seminal vesicle invasion significantly correlated with BCR especially in high risk group (11 and 13 of 15 patients, p < 0.05, resp.). Conclusion. CAPRA-S score can be easily calculated and it is useful in clinical practice in order to timely propose adjuvant therapies after surgery.

Switching and withdrawing hormonal agents for castration-resistant prostate cancer

The antiandrogen withdrawal syndrome (AAWS) is characterized by tumour regression and a decline in serum PSA on discontinuation of antiandrogen therapy in patients with prostate cancer. This phenomenon has been best described with the withdrawal of the nonsteroidal antiandrogens, bicalutamide and flutamide, but has also been reported with a wide range of hormonal agents. Mutations that occur in advanced prostate cancer and induce partial activation of the androgen receptor (AR) by hormonal agents have been suggested as the main causal mechanism of the AAWS. Corticosteroids, used singly or in conjunction with abiraterone, docetaxel and cabazitaxel might also be associated with the AAWS. The discovery of the Phe876Leu mutation in the AR, which is activated by enzalutamide, raises the possibility of withdrawal responses to novel hormonal agents. This Review focusses on the molecular mechanisms responsible for withdrawal responses, the role of AR mutations in the development of treatment resistance, and the evidence for the sequential use of antiandrogens in prostate cancer therapy. The implications of AR mutations for the development of novel drugs that target the AR are discussed, as are the challenges associated with redefining the utility of older treatments in the current therapeutic landscape.

Aberrant Protocadherin17 (PCDH17) Methylation in Serum is a Potential Predictor for Recurrence of Early-Stage Prostate Cancer Patients After Radical Prostatectomy

Background

Prostate cancer is a one of the most common malignant diseases in men worldwide. Now it is a challenge to identify patients at higher risk for relapse and progression after surgery, and more novel prognostic biomarkers are needed. The aim of this study was to investigate the clinical significance of protocadherin17 (PCDH17) methylation in serum and its predictive value for biochemical recurrence (BCR) after radical prostatectomy.

Material/Methods

We evaluated the methylation status of PCDH17 in serum samples of 167 early-stage prostate cancer patients and 44 patients with benign prostatic hyperplasia (BPH) using methylation-specific PCR (MSP), and then evaluated the relationship between PCDH17 methylation and clinicopathologic features. Kaplan-Meier survival analysis and Cox analysis were used to evaluate its predictive value for BCR.

Results

The ratio of PCDH17 methylation in prostate cancer patients was higher than in patients with BPH. Moreover, PCDH17 methylation was significantly associated with advanced pathological stage, higher Gleason score, higher preoperative PSA levels, and BCR. Kaplan-Meier survival analysis indicated that patients with methylated PCDH17 had shorter BCR-free survival time compared to patients with unmethylated PCDH17. Cox regression analysis indicated that PCDH17 methylation was an independent predictive factor for the BCR of patients after radical prostatectomy.

Conclusions

PCDH17 methylation in serum is a frequent event in early-stage prostate cancer, and it is an independent predictor of BCR after radical prostatectomy.

Intensity-modulated salvage radiotherapy with simultaneous integrated boost for local recurrence of prostate carcinoma: a pilot study on the place of PET-choline for guiding target volume delineation

OBJECTIVE

The aim of this study was to report the first cases of salvage radiotherapy (RT) using the intensity-modulated radiotherapy (IMRT) with simultaneous integrated boost (SIB) targeted on choline positron emission tomography (PET) uptake in a local recurrent prostate cancer, after a radical prostatectomy.

METHODS

Four patients received salvage irradiation for biochemical relapse that occurred after the initial radical prostatectomy. The relapse occurred from 10 months to 6 years with PSA levels ranging from 2.35 to 4.86 ng ml(-1). For each patient, an (18)F-choline PET-CT showed a focal choline uptake in prostatic fossa, with standardized uptake value calculated on the basis of predicted lean body mass (SUL) max of 3.3-6.8. No involved lymph node or distant metastases were diagnosed. IMRT doses were of 62.7 Gy (1.9 Gy/fraction, 33 fractions), with a SIB of 69.3 Gy (2.1 Gy/fraction, 33 fractions) to a PET-guided target volume.

RESULTS

Acute toxicities were limited. We observed no gastrointestinal toxicity ≥grade 2 and only one grade 2 genitourinary toxicity. At 1-month follow-up evaluation, no complication and a decrease in PSA level (6.8-43.8% of the pre-therapeutic level) were reported. After 4 months, a decrease in PSA level was obtained for all the patients, ranging from 30% to 70%. At a median follow-up of 15 months, PSA level was controlled for all the patients, but one of them experienced a distant lymph node recurrence.

CONCLUSION

Salvage irradiation to the prostate bed with SIB guided by PET-CT is feasible, with biological efficacy and no major acute toxicity.

ADVANCES IN KNOWLEDGE

IMRT with PET-oriented SIB for salvage treatment of prostate cancer is possible, without major acute toxicity.

DNA damage induces GDNF secretion in the tumor microenvironment with paracrine effects promoting prostate cancer treatment resistance

Though metastatic cancers often initially respond to genotoxic therapeutics, acquired resistance is common. In addition to cytotoxic effects on tumor cells, DNA damaging agents such as ionizing radiation and chemotherapy induce injury in benign cells of the tumor microenvironment resulting in the production of paracrine-acting factors capable of promoting tumor resistance phenotypes. In studies designed to characterize the responses of prostate and bone stromal cells to genotoxic stress, we found that transcripts encoding glial cell line-derived neurotrophic factor (GDNF) increased several fold following exposures to cytotoxic agents including radiation, the topoisomerase inhibitor mitoxantrone and the microtubule poison docetaxel. Fibroblast GDNF exerted paracrine effects toward prostate cancer cells resulting in enhanced tumor cell proliferation and invasion, and these effects were concordant with the expression of known GDNF receptors GFRA1 and RET. Exposure to GDNF also induced tumor cell resistance to mitoxantrone and docetaxel chemotherapy. Together, these findings support an important role for tumor microenvironment damage responses in modulating treatment resistance and identify the GDNF signaling pathway as a potential target for improving responses to conventional genotoxic therapeutics.

NDRG2 acts as a negative regulator downstream of androgen receptor and inhibits the growth of androgen-dependent and castration-resistant prostate cancer

Castration resistance is a major issue during castration therapy for prostate cancer and thus more effective treatment are needed for castration-resistant prostate cancer (CRPC). NDRG2 (N-Myc downstream regulated gene 2), a recently identified tumor suppressor, was previously shown to inhibit the proliferation and invasion of prostate cancer, but whether NDRG2 is involved in CRPC remains to be known. Because androgen receptor (AR) axis plays an important role in castration resistance, we evaluate the role of NDRG2 in AR signaling and CRPC. Immunohistochemistry examination of prostate cancer tissues demonstrated that the expression of NDRG2 is negatively correlated with that of AR and c-Myc. Furthermore, AR negatively regulates NDRG2, as well as alters levels of c-Myc and prostate specific antigen (PSA). Forced expression of NDRG2 significantly inhibits the in vitro growth of androgen-dependent and castration-resistant prostate cancer cells; this was accompanied by alterations in PSA, but not by those of AR and c-Myc. Finally, by mimicking castration therapy in a xenograft mouse model, we showed that lentivirus-mediated NDRG2 overexpression efficiently overcomes castration resistance. Thus, by acting as a negative regulator downstream of AR, NDRG2 may emerge as a potential therapy molecule for CRPC.

Radiotherapy for isolated lymph node metastases in patients with locally advanced prostate cancer after primary therapy

PURPOSE

To evaluate the outcome of radiotherapy for isolated lymph node metastases in patients with progression towards castration-resistant prostate cancer (CRPC) after definitive therapy.

METHODS

Between 11/2009 and 06/2014, 18 patients with isolated lymph node metastases after definitive prostate cancer therapy received radiotherapy to the affected lymph nodes with a total dose of 50.4 or 54.0 Gray (Gy). All patients had continuously rising levels of PSA despite androgen deprivation therapy (ADT). Biochemical progression-free survival (BPFS), clinical failure-free survival (CFFS) and freedom from local failure were assessed, as was the toxicity profile.

RESULTS

Of the 18 patients, 17 had high-risk prostate cancer. Radiotherapy was performed at a median interval of 64.55 [interquartile range (IQR) 23.2-153.8] months after definitive therapy. ADT was administered for a median (IQR) time of 3.8 (3.2-24.7) months prior to irradiation. The median (IQR) follow-up was 15.59 (5.3-28.5) months with 94.1 % freedom from local failure. The median BPFS and CFFS were 5.85 (IQR 3.0-20.3) and 9.60 months (IQR 5.9-28.8), respectively. No grade III acute or grade II late toxicity was observed. Only two patients developed local relapse. No patients exhibited deterioration of urinary or faecal continence.

CONCLUSION

Radiotherapy of isolated lymph node metastases in patients who develop CRPC provides effective local control, is not associated with clinically important acute or long-term side effects, improves PSA kinetics and may delay the necessity of chemotherapy.

Systemic Medical Treatment in Men with Metastatic Castration-Resistant Prostate Cancer: Recommendations for Daily Routine

The approval or clinical evaluation of several new agents - cabazitaxel, abiraterone acetate, enzalutamide, sipuleucel-T, and radium-223 - has significantly changed the management of patients with metastatic castration-resistant prostate cancer (mCRPC) prior to or after docetaxel-based chemotherapy. All of these agents have resulted in a significant survival benefit as compared to their control group. However, treatment responses might differ depending on the associated comorbidities and the extent and biological aggressiveness of the disease. Furthermore, treatment-associated side effects differ between the various drugs. As new drugs become approved, new treatment strategies and markers to best select which patients will best respond to which drug are needed. It is the aim of the current article to i) summarize the data of established treatment options in mCRPC, ii) highlight new developments in medical treatment, iii) provide clinically useful algorithms for the daily routine, and iv) point out future developments in medical treatment.

Bisphosphonates for cancer treatment: Mechanisms of action and lessons from clinical trials

A growing body of evidence points toward an important anti-cancer effect of bisphosphonates, a group of inexpensive, safe, potent, and long-term stable pharmacologicals that are widely used as osteoporosis drugs. To date, they are already used in the prevention of complications of bone metastases. Because the bisphosphonates can also reduce mortality in among other multiple myeloma, breast, and prostate cancer patients, they are now thoroughly studied in oncology. In particular, the more potent nitrogen-containing bisphosphonates have the potential to improve prognosis. The first part of this review will elaborate on the direct and indirect anti-tumoral effects of bisphosphonates, including induction of tumor cell apoptosis, inhibition of tumor cell adhesion and invasion, anti-angiogenesis, synergism with anti-neoplastic drugs, and enhancement of immune surveillance (e.g., through activation of γδ T cells and targeting macrophages). In the second part, we shed light on the current clinical position of bisphosphonates in the treatment of hematological and solid malignancies, as well as on ongoing and completed clinical trials investigating the therapeutic effect of bisphosphonates in cancer. Based on these recent data, the role of bisphosphonates is expected to further expand in the near future outside the field of osteoporosis and to open up new avenues in the treatment of malignancies.

Alterations in androgen deprivation enhanced prostate-specific membrane antigen (PSMA) expression in prostate cancer cells as a target for diagnostics and therapy

BACKGROUND

Prostate-specific membrane antigen (PSMA) is a promising target for diagnostics and therapy of prostate carcinoma (PCa). Based on the hypothesis that PSMA expression can be modulated by variations in androgen deprivation therapy (ADT), we investigated the binding of a PSMA-directed radiopharmaceutical in vitro in order to get an insight of the interactions between altered premedication and PSMA expression before repetitive PSMA-directed PET/CT for therapy response and targeted therapy implementation.

METHODS

The human castration-resistant PCa cell line VCaP (CRPC) was treated with either 1 nmol/L testosterone (T) over 20 passages yielding the androgen-sensitive cell line (revCRPC) or with 5 μmol/L abiraterone acetate (AA) generating the abiraterone-tolerant subtype CRPCAA. In these cell lines, T and AA were varied by either supply or withdrawal of T and AA. PSMA expression of the three cell culture models was detected by Western blot and immunohistochemical staining. For quantitative measurement of tracer uptake, 0.3 nmol/L (68)Ga-labelled PSMA-HBED-CC peptide (100-300 kBq/ml) was added to different treated parallel cultures (n = 9 each). Time-dependent uptake per 10(6) cells of each culture was calculated and evaluated. PSMA mRNA expression was investigated by qPCR.

RESULTS

PSMA expression increased dependently on intensified ADT in all three basic cell lines. (68)Ga-PSMA-HBED-CC uptake almost doubled during 3 h in all cell lines (p < 0.01). Compared to the basic cells, pre-incubation with abiraterone for 48 h resulted in a significant increased uptake in CRPC (p < 0.001). In revCRPC, 48-h AA pre-incubation resulted in an eightfold higher uptake after 3 h (p < 0.001). Additional withdrawal of external testosterone increased the uptake up to tenfold (p < 0.01). The increase of PSMA expression upon ADT and AA treatments was confirmed by qPCR and Western blot data. Furthermore, in CRPCAA, 48-h AA withdrawal increased the uptake up to fivefold (p < 0.01).

CONCLUSIONS

The investigated three PCa cell culture subtypes represent a serial preclinical model of androgen deprivation therapy as a proxy for clinical situations with differing basal PSMA expression. The uptake of PSMA-binding tracers could be stimulated by therapeutic effective short-term variation in premedication in all stages of ADT response. These complex interactions have to be considered in the interpretation of diagnostic imaging using PSMA ligands as well as in the optimal timing of PSMA-based therapies.

The Immune Checkpoint Regulator PD-L1 Is Highly Expressed in Aggressive Primary Prostate Cancer

PURPOSE

Therapies targeting the programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) pathway promote anti-tumor immunity and have shown promising results in various tumors. Preliminary data further indicate that immunohistochemically detected PD-L1 may be predictive for anti-PD-1 therapy. So far, no data are available on PD-L1 expression in primary prostate cancer.

EXPERIMENTAL DESIGN

Following validation of a monoclonal antibody, immunohistochemical analysis of PD-L1 expression was performed in two independent, well-characterized cohorts of primary prostate cancer patients following radical prostatectomy (RP), and resulting data were correlated to clinicopathological parameters and outcome.

RESULTS

In the training cohort (n= 209), 52.2% of cases expressed moderate to high PD-L1 levels, which positively correlated with proliferation (Ki-67,P< 0.001), Gleason score (P= 0.004), and androgen receptor (AR) expression (P< 0.001). Furthermore, PD-L1 positivity was prognostic for biochemical recurrence [BCR;P= 0.004; HR, 2.37; 95% confidence interval (CI), 1.32-4.25]. In the test cohort (n= 611), moderate to high PD-L1 expression was detected in 61.7% and remained prognostic for BCR in univariate Cox analysis (P= 0.011; HR, 1.49; 95% CI, 1.10-2.02). The correlation of Ki-67 and AR with PD-L1 expression was confirmed in the test cohort (P< 0.001). In multivariate Cox analysis of all patients, PD-L1 was corroborated as independently prognostic for BCR (P= 0.007; HR, 1.46; 95% CI, 1.11-1.92).

CONCLUSIONS

We provide first evidence that expression of the therapy target PD-L1 is not only highly prevalent in primary prostate cancer cells but is also an independent indicator of BCR, suggesting a biologic relevance in primary tumors. Further studies need to ascertain if PD-1/PD-L1-targeted therapy might be a treatment option for hormone-naïve prostate cancers.

Prediction of biochemical recurrence after radical prostatectomy with PI-RADS version 2 in prostate cancers: initial results

OBJECTIVES

To determine whether the Prostate Imaging Reporting and Data System version 2 (PI-RADSv2) helps predict biochemical recurrence (BCR) after radical prostatectomy for prostate cancer (PCa).

METHODS

We included 158 patients with PCa who underwent magnetic resonance imaging (MRI) and radical prostatectomy (RP). Clinical (prostate-specific antigen, greatest percentage of core, and percentage of positive core number), PI-RADSv2 score on MRI, and surgical parameters (Gleason score, extracapsular extension, seminal vesicle invasion, and tumour volume) were investigated. Univariate and multivariate analyses using Cox's proportional hazards model were performed to assess parameters predictive of BCR (two consecutive prostate specific antigens ≥0.2 ng/ml). Kaplan-Meier survival curves were analyzed.

RESULTS

The rate of BCR was 13.3 % (21/158) after surgery (median follow-up, 25 months; range, 12-36). No subject with a PI-RADS score <4 had BCR. In univariate analysis, all parameters were significant for BCR (p < 0.05), except seminal vesicle invasion (p = 0.254). Meanwhile, PI-RADS score was the only independent parameter for BCR in multivariate analysis (p < 0.05). Two-year, BCR-free survival post-RP was significantly lower for PI-RADS ≥4 (84.7-85.5 %) than for PI-RADS <4 (100 %; p < 0.05).

CONCLUSION

As a preoperative imaging tool, PI-RADSv2 may be useful to predict BCR after radical prostatectomy for PCa.

KEY POINTS

• No subject with PI-RADS <4 had BCR after RP • PI-RADSv2 was the only predictor of BCR in multivariate analysis • Two-year, BCR-free survival following RP was lower for PI-RADS≥4 than for PI-RADS<4 • Inter-rater agreement was good for PI-RADS ≥4 or not.

The outcome and prognostic factors for lymph node recurrence after node-sparing definitive external beam radiotherapy for localized prostate cancer

Background

The prognostic factors for the recurrence of lymph node (LN) metastasis after dose-escalated radiotherapy (RT) in prostate cancer patients have not been well investigated. We report the prognostic factors and outcomes in patients receiving salvage treatment for LN recurrence after high-dose intensity-modulated RT (IMRT).

Methods

We studied a cohort of 419 patients with localized prostate adenocarcinoma undergoing definitive IMRT (78 Gy). LN recurrence was diagnosed by size criteria using computed tomography (CT) or magnetic resonance imaging, or abnormal uptake of ¹⁸F-fluorocholine by LNs on positron emission tomography/CT. Overall survival and LN recurrence-free survival (LNRFS) were calculated, and prognostic factors were evaluated.

Results

With a median follow-up of 60 months, 18 patients (4.3 %) had LN recurrence and a significantly lower 5-year overall survival rate (60 vs. 90 %, p = 0.003). Univariate analysis showed that T3/T4 stage (p = 0.003), Gleason score >7 (p < 0.001), and estimated risk of pelvic LN involvement of >30 % by the Roach formula (p = 0.029) were associated with significantly lower LNRFS. On multivariate analysis, high Gleason score (hazard ratio = 5.99, p = 0.007) was the only independent factor. The 1/2-year overall survivals after LN recurrence were 67/54 %. Patients with isolated LN recurrence (p = 0.003), prostate-specific antigen (PSA) doubling time >5 months (p = 0.009), interval between PSA nadir and biochemical failure >12 months (p = 0.035), and PSA <10 ng/ml at LN recurrence (p = 0.003) had significantly better survival. Patients with isolated LN recurrence had significantly better survival when treated with combined RT and hormones than when treated with hormones alone (p = 0.011).

Conclusions

Gleason score of >7 may predict LN recurrence in prostate cancer patients treated with definitive IMRT. Small number of patients limits the extrapolation of this risk with the primary treatment strategy. Combined RT and hormones may prolong survival in patients with isolated LN recurrence.

Bone health and its correlates in Korean prostate cancer patients receiving androgen deprivation therapy

PURPOSE

This study aimed to examine bone health status, identify factors associated with bone mineral density (BMD), and determine potential risk factors for osteoporosis in Korean prostate cancer patients receiving androgen deprivation therapy (ADT).

METHODS

Using a cross-sectional descriptive design, we recruited 139 men with prostate cancer receiving ADT at two university-based hospitals in South Korea. Participants completed a self-reported questionnaire and underwent dual energy X-ray absorptiometry testing. BMD (gm/cm(2)), bone health status (normal BMD, osteopenia, and osteoporosis), and lifestyle variables (physical activity, smoking, and alcohol consumption) were measured.

RESULTS

The prevalence in our sample was 49.6% for osteopenia and 17.3% for osteoporosis. In multivariate linear regression analyses, BMD was positively associated with body mass index, number of comorbidities, and level of physical activity and negatively associated with being unemployed or retired, having a lower monthly income, and being treated with gonadotropin-releasing hormone therapy alone. In logistic regression analyses, potential risk factors for osteoporosis were low monthly income (OR = 4.33, p = 0.011), receipt of radiation therapy (OR = 4.69, p = 0.018), and lack of regular physical activity (OR = 2.63, p = 0.035).

CONCLUSIONS

Our results suggest that a proportion of prostate cancer survivors who are receiving ADT warrant monitoring to prevent osteoporosis, particularly men of lower economic status and those having lower levels of physical activity. Nurses can play an important role in screening these high risk groups.

Adaptive responses of androgen receptor signaling in castration-resistant prostate cancer

Prostate Cancer (PCa) is an important age-related disease being the most common cancer malignancy and the second leading cause of cancer mortality in men in Western countries. Initially, PCa progression is androgen receptor (AR)- and androgen-dependent. Eventually advanced PCa reaches the stage of Castration-Resistant Prostate Cancer (CRPC), but remains dependent on AR, which indicates the importance of AR activity also for CRPC. Here, we discuss various pathways that influence the AR activity in CRPC, which indicates an adaptation of the AR signaling in PCa to overcome the treatment of PCa. The adaptation pathways include interferences of the normal regulation of the AR protein level, the expression of AR variants, the crosstalk of the AR with cytokine tyrosine kinases, the Src-Akt-, the MAPK-signaling pathways and AR corepressors. Furthermore, we summarize the current treatment options with regard to the underlying molecular basis of the common adaptation processes of AR signaling that may arise after the treatment with AR antagonists, androgen deprivation therapy (ADT) as well as for CRPC, and point towards novel therapeutic strategies. The understanding of individualized adaptation processes in PCa will lead to individualized treatment options in the future.

Synergistic anticancer efficacy of MEK inhibition and dual PI3K/mTOR inhibition in castration-resistant prostate cancer

BACKGROUND

PTEN deletion, mutation or reduced expression occurs in 63% of metastatic prostate tumors, resulting in the activation of PI3K and its downstream targets, AKT and mTOR. Inhibition of the PI3K pathway results in upregulation of the MAPK pathway. Therefore, co-administration of inhibitors of both pathways, GSK2126458 as a dual PI3K/mTOR inhibitor, and AZD6244 as a MEK inhibitor, is able to overcome resistance and increase anti-tumor efficacy.

METHODS

PC3, DU145, LNCaP, and CRPC patient-derived cells were used to assess apoptosis upon exposure to the drug combination. The human DU145 and PC3 tumor xenograft mouse model was employed to evaluate in vivo efficacy. CellTiter Glo® luminescent assay, annexin V-FITC apoptosis detection, cell cycle analysis, Western blotting and immunohistochemistry were conducted. Statistical evaluation of the results was performed by one-way ANOVA.

RESULTS

The combination of GSK2126458 and AZD6244 inhibited the growth of DU145 and PC3 prostate cancer cells in vitro and in vivo. GSK2126458 decreased phospho-AKT while increasing phospho-ERK and AZD6244 decreased phospho-ERK efficiently while increasing phospho-AKT. The combination of GSK2126458 and AZD6244 decreased both phospho-AKT and phospho-ERK effectively in vitro and in vivo. The combination treatment synergistically induced annexin V-positive cells, sub-G1 cells, and cleavage of caspase-9, caspase-3 and poly-ADP ribose polymerase (PARP) in DU145 cells in vitro. Moreover, the combination decreased the level of Ki-67, and increased TUNEL-positive cells and cleaved caspase-3 in DU145 xenograft tumors implanted in mice. In addition, this combination treatment inhibited both the PI3K and MEK pathway primary in cultures from CRPC patients harboring PTEN loss, leading to synergistic anti-tumor effect.

CONCLUSIONS

The combination of GSK2126458 and AZD6244 blocks both the RAS/RAF/MEK/ERK and PI3K/AKT/mTOR pathways simultaneously and is an effective strategy for the treatment of CRPCs.

Prognostic factors after salvage radiotherapy alone in patients with biochemical recurrence after radical prostatectomy

OBJECTIVES

To evaluate the oncological outcome and to assess prognostic factors of salvage radiotherapy alone in patients with biochemical recurrence after radical prostatectomy.

METHODS

We reviewed our single institution, prospectively maintained database of 2043 patients who underwent radical prostatectomy between September 1995 and December 2011. In this cohort, 149 patients who developed biochemical recurrence after radical prostatectomy and received salvage radiotherapy alone after pelvic magnetic resonance imaging were included. Three-dimensional conformal radiotherapy or intensity-modulated radiotherapy was delivered with a median dose of 70.0 Gy (66.0-78.0 Gy) or 67.2 Gy (64.8-70.0 Gy). Kaplan-Meier and Cox regression analyses were carried out.

RESULTS

With a median follow up of 82 months (range 20-153 months), 55 patients (36.9%) failed salvage radiotherapy. The 5-year salvage radiotherapy failure-free probability was 53.6%. On multivariate analysis, pre-salvage radiotherapy prostate-specific- antigen ≥ 1.0 ng/mL (P = 0.003, hazard ratio 3.592, 95% confidence interval 1.522-8.579), pathological stage ≥ T3a (P = 0.004, hazard ratio 2.261, 95% confidence interval 1.290-3.833), pathological Gleason score ≥ 7 (P = 0.018, hazard ratio 5.501, 95% confidence interval 1.577-21.221), prostate-specific antigen doubling time < 12 months (P = 0.014, hazard ratio 2.243, 95% confidence interval 1.177-4.275) and no visible lesion on pelvic magnetic resonance imaging (P = 0.016, hazard ratio 2.068, 95% confidence interval 1.268-3.501) were independent prognostic factors of salvage radiotherapy failure after radical prostatectomy.

CONCLUSIONS

Pre-salvage radiotherapy prostate-specific antigen ≥ 1.0 ng/mL, pathological stage ≥ T3a, pathological Gleason score ≥ 7, prostate-specific antigen doubling time < 12 months and no visible lesion on pelvic magnetic resonance imaging are prognostic factors of salvage radiotherapy failure after radical prostatectomy. We should consider additional treatment in patients with these factors for favorable outcomes.

Prior Endocrine Therapy Impact on Abiraterone Acetate Clinical Efficacy in Metastatic Castration-resistant Prostate Cancer: Post-hoc Analysis of Randomised Phase 3 Studies

BACKGROUND

The duration of prior hormonal treatment can predict responses to subsequent therapy in patients with metastatic castration-resistant prostate cancer (mCRPC).

OBJECTIVE

To determine if prior endocrine therapy duration is an indicator of abiraterone acetate (AA) sensitivity.

DESIGN, SETTING, AND PARTICIPANTS

Post-hoc exploratory analysis of randomised phase 3 studies examining post-docetaxel (COU-AA-301) or chemotherapy-naïve mCRPC (COU-AA-302) patients receiving AA. The treatment effect on overall survival (OS), radiographic progression-free survival (rPFS), and prostate-specific antigen (PSA) response analysed by quartile duration of prior gonadotropin-releasing hormone agonists (GnRHa) or androgen receptor (AR) antagonist.

INTERVENTION

Patients were randomised to AA (1000mg, orally once daily) plus prednisone (5mg, orally twice daily) or placebo plus prednisone. Prior endocrine therapy was GnRHa (COU-AA-301, n=1127 [94%]; COU-AA-302, n=1057 [97%], 45.1 mo or 36.7 mo median duration, respectively) and/or orchiectomy (COU-AA-301, n=78 [7%] COU-AA-302, n=44 [4%]); castrated patients received prior AR antagonists (COU-AA-301, n=1015 [85%]; COU-AA-302, n=1078 [99%], 15.7 mo or 16.1 mo median duration, respectively).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Cox model was used to obtain hazard ratio and associated 95% confidence interval with statistical inference by log rank statistic.

RESULTS AND LIMITATIONS

Clinical benefit with AA was observed for OS, rPFS, and PSA response for nearly all quartiles with GnRHa or AR antagonists in both COU-AA-301 and COU-AA-302. In COU-AA-301, patients with a longer duration of prior endocrine therapy tended to have greater AA OS, rPFS, and PSA response benefit, with lead-time chemotherapy bias potentially impacting COU-AA-301 results. Time to castration resistance was not captured. This analysis is limited as a post-hoc exploratory analysis.

CONCLUSIONS

In the COU-AA-301 and COU-AA-302 studies, AA produced clinical benefits regardless of prior endocrine therapy duration in patients with mCRPC.

PATIENT SUMMARY

Metastatic castration-resistant prostate cancer patients derived clinical benefits with abiraterone acetate regardless of prior endocrine therapy duration.

Management of metastatic hormone-sensitive prostate cancer

In 2014, prostate cancer will affect roughly 15 % of American men during their lifetimes with about 230,000 new cases and 29,000 deaths per year. If required, most can be treated with curative surgery or radiotherapy. Upon relapse, androgen deprivation therapy (intermittent or continuous) is the cornerstone of treatment for hormone-sensitive disease. Response is variable and treatment is associated with a significant risk of toxicity. Recently, significant advances in survival have been demonstrated with chemohormonal therapy in men with high-volume disease. In addition, new findings have informed the approach to preventing bone complications in patients on therapy for metastatic hormone-sensitive prostate cancer. Devising clinical prediction tools and biomarkers is needed to select patients most likely to benefit from certain therapies and allow for a personalized approach.

Drug-induced osteoporosis: from Fuller Albright to aromatase inhibitors

Many commonly prescribed medications, such as selective serotonin reuptake inhibitors, proton pump inhibitors, thiazolidinediones, aromatase inhibitors, and androgen deprivation therapy, have been associated with adverse skeletal effects. The levels of evidence in support of a causal relationship between drug use and the development of bone loss and fractures are variable. For some drugs, a causal relationship is suspected (but not proven) based on observational studies, while in others causality is firmly established with randomized, controlled clinical trials. The mechanism of action for skeletal damage is poorly understood for some drugs and well known for others. Guidelines for managing bone health in patients taking some medications with potential skeletal toxicity have been developed using the best available evidence and expert opinion. This is a review of selected medications that have been associated with bone loss and fractures, with recommendations for clinical care.

Assessing the Optimal Timing for Early Salvage Radiation Therapy in Patients with Prostate-specific Antigen Rise After Radical Prostatectomy

BACKGROUND

Early salvage radiation therapy (eSRT) represents a treatment option for patients who experience a prostate-specific antigen (PSA) rise after radical prostatectomy (RP); however, the optimal PSA level for eSRT administration is still unclear.

OBJECTIVE

To test the impact of PSA level on cancer control after eSRT according to pathologic tumour characteristics.

DESIGN, SETTING, AND PARTICIPANTS

The study included 716 node-negative patients with undetectable postoperative PSA who experienced a PSA rise after RP. All patients received eSRT, defined as local radiation to the prostate and seminal vesicle bed, delivered at PSA ≤ 0.5 ng/ml. Biochemical recurrence (BCR) after eSRT was defined as two consecutive PSA values ≥ 0.2 ng/ml.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Multivariable Cox regression analysis tested the association between pre-eSRT PSA level and BCR after eSRT. Covariates consisted of pathologic stage (pT2 vs pT3a vs pT3b or higher), pathologic Gleason score (≤ 6, 7, or ≥ 8), and surgical margin status (negative vs positive). We tested an interaction with PSA level and baseline pathologic risk for the hypothesis that BCR-free survival differed by pre-eSRT PSA level. Three pathologic risk factors were identified: pathologic stage pT3b or higher, pathologic Gleason score ≥ 8, and negative surgical margins.

RESULTS AND LIMITATIONS

Median follow-up among patients who did not experience BCR after eSRT was 57 mo (interquartile range: 27-105). At 5 yr after eSRT, BCR-free survival rate was 82% (95% confidence interval [CI], 78-85). At multivariable Cox regression analysis, pre-eSRT PSA level was significantly associated with BCR after eSRT (hazard ratio: 4.89; 95% CI, 1.40-22.9; p < 0.0001). When patients were stratified according to the number of risk factors at final pathology, patients with at least two pathologic risk factors showed an increased risk of 5-yr BCR as high as 10% per 0.1 ng/ml of PSA level compared with only 1.5% in patients with one or no pathologic risk factors.

CONCLUSIONS

In this retrospective study, cancer control after eSRT greatly depended on pretreatment PSA. The absolute PSA level had a different prognostic value depending on the pathologic characteristics of the tumour. In patients with more adverse pathologic features, eSRT conferred better cancer control when administered at the very first sign of PSA rise. Conversely, the benefit of eSRT was less evident in men with favourable disease at RP.

PATIENT SUMMARY

In this retrospective study, cancer control after early salvage radiation therapy (eSRT) was influenced by pretreatment prostate-specific antigen (PSA) level. This effect was highest in men with at least two of the following pathologic features: pT3b/pT4 disease, pathologic Gleason score ≥ 8, and negative surgical margins. In these patients, eSRT conferred better cancer control when administered at the very first sign of PSA rise.

Changing Patterns of Primary Treatment in Korean Men with Prostate Cancer Over 10 Years: A Nationwide Population Based Study

PURPOSE

We investigated changing patterns of primary treatment in Korean men with prostate cancer (PC) and impact of sociodemographic factors on treatment choice from a nationwide cohort over 10 years.

MATERIALS AND METHODS

We conducted a cohort study of a 2% nationwide random sample of Korean National Health Insurance. A total of 1,382 patients who had undergone active treatments for newly diagnosed PC between 2003 and 2013 were included. Time trends in primary treatment of PC, including radical surgery, radiation therapy (RT), and androgen deprivation therapy (ADT) were analyzed.

RESULTS

Total number of patients undergoing active treatments increased significantly (162%). Surgery cases showed the most significant increase, from 22.4% in 2003 to 45.4% in 2013, while the relative proportion of ADT showed a tendency to decrease from 60.3% in 2003 to 45.4% in 2013, and the relative proportion of RT was variable over 10 years (from 7.2% to 18.4%). While treatment patterns differed significantly according to age (p < 0.001) and income classes (p=0.014), there were differences in primary treatment according to residential area. In multinomial logistic regression analysis, older patients showed significant association with ADT or RT compared to surgery, while patients with higher income showed significant association with surgery.

CONCLUSION

Treatment pattern in Korean PC patients has changed remarkably over the last 10 years. Sociodemographic factors do affect the primary treatment choice. Our results will be valuable in overviewing changing patterns of primary treatment in Korean PC patients and planning future health policy for PC.