Vascular Targeted Photodynamic Therapy for Localized Prostate Cancer

Survival for men diagnosed with prostate cancer directly depends on the stage and grade of the disease at diagnosis. Prostate cancer screening has greatly increased the ability to diagnose small and low-grade cancers that are amenable to cure. However, widespread prostate-specific antigen screening exposes many men with low-risk cancers to unnecessary complications associated with treatment for localized disease without any survival advantage. One challenge for urological surgeons is to develop effective treatment options for low-risk disease that are associated with fewer complications. Minimally invasive ablative treatments for localized prostate cancer are under development and may represent a preferred option for men with low-risk disease who want to balance the risks and benefits of treatment. Vascular targeted photodynamic therapy (VTP) is a novel technique that is being developed for treating prostate cancer. Recent advances in photodynamic therapy have led to the development of photosynthesizers that are retained by the vascular system, which provides the opportunity to selectively ablate the prostate with minimal collateral damage to other structures. The rapid clearance of these new agents negates the need to avoid exposure to sunlight for long periods. Presented herein are the rationale and preliminary data for VTP for localized prostate cancer.Key words: Prostate cancer, localized; Minimally invasive ablative treatment for prostate cancer; Photodynamic therapy; WST-09; WST-11; Vascular targeted photodynamic therapy; Padoporfin; Palladium bacteriopheophorbideProstate cancer represents the second most common cause of cancer-related deaths in American men; it is estimated that 27,000 men in the United States died from the disease in 2007.¹ Survival for men with prostate cancer directly depends on the stage and grade of the disease at the time of diagnosis.² These sobering mortality statistics and the more favorable prognosis associated with early detection provide the primary justification for prostate cancer screening, which is performed by measuring the level of serum prostate-specific antigen (PSA) and conducting a digital rectal examination (DRE). It is estimated that 50% of men over the age of 50 years are screened annually for prostate cancer.³Despite widespread acceptance, prostate cancer screening is debated,^4,5 and recommendations for prostate cancer screening are inconsistent. Screening protagonists emphasize that radical prostatectomy increases prostate cancer survival in men with localized disease,⁶ and that the recently observed progressive and significant decline in prostate cancer mortality rates is the direct result of PSA screening and aggressive intervention.⁷ Screening antagonists emphasize the indolent natural history of most prostate cancers detected by screening,⁸ and that the vast majority of men who are treated for prostate cancer do not recognize any survival advantage from early detection and are simply left suffering the ravages of treatment.⁹Both sides of the screening debate have valid arguments. In the absence of widespread screening, many men are denied an opportunity to cure their disease. These men will experience the otherwise preventable consequences of disease progression, which include the development of androgen-insensitive disease¹⁰ and death. However, widespread screening exposes many men to unnecessary complications associated with treatment for localized disease. The challenges are to identify and treat only those cancers that have the biological potential to cause serious and preventable consequences, or to develop treatment options that are associated with fewer complications.     

Widespread and Functional RNA Circularization in Localized Prostate Cancer

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Proton Beam Therapy for Localized Prostate Cancer 101: Basics,Controversies, and Facts

Proton beam therapy for prostate cancer has become a source of controversy in the urologic community, and the rapid dissemination and marketing of this technology has led to many patients inquiring about this therapy. Yet the complexity of the technology, the cost, and the conflicting messages in the literature have left many urologists ill equipped to counsel their patients regarding this option. This article reviews the basic science of the proton beam, examines the reasons for both the hype and the controversy surrounding this therapy, and, most importantly, examines the literature so that every urologist is able to comfortably discuss this option with inquiring patients.Key words: Prostate cancer, Proton beam therapy, External beam radiation therapy, Intensity modulated radiation therapyProton beam therapy (PBT) has become a source of controversy in the urologic community. It is not uncommon to hear mixed messages regarding the issue, from zealous advocates to cost-conscious skeptics, leaving many urologists unsure what to tell their patients with prostate cancer. What is clear, however, is that the technology is disseminating across the nation, and as our patients turn to the internet to learn more about their diagnosis, they are going to encounter increasingly more information about PBT, both scientific and promotional in nature. Hence, it is necessary for every urologist to understand the basics of PBT to help guide our patients through treatment options. This article reviews and compares the basic science of conventional external beam radiation therapy (EBRT) with PBT, examines the reasons for both the hype and the controversy surrounding this therapy, and, most importantly, examines the literature so that all urologists are adequately equipped to counsel their patients on this subject.     

Focal Laser Ablation for Localized Prostate Cancer: Principles,Clinical Trials,and Our Initial Experience

Focal therapy of prostate cancer is an evolving treatment strategy that destroys a predefined region of the prostate gland that harbors clinically significant disease. Although long-term oncologic control has yet to be demonstrated, focal therapy is associated with a marked decrease in treatment-related morbidity. Focal laser ablation is an emerging modality that has several advantages, most notably real-time magnetic resonance imaging (MRI) compatibility. This review presents the principles of laser ablation, the role of multiparametric MRI for delineating the site of significant prostate cancer, a summary of published clinical studies, and our initial experience with 23 patients, criteria for selecting candidates for focal prostate ablation, and speculation regarding future directions.Key words: Laser ablation, Prostate cancer, Focal therapy, Targeted therapyProstate cancer is the most common solid organ malignancy and the second most common cause of cancer death among men living in the Western world.¹ Widespread prostate-specific antigen (PSA) testing and decreased thresholds for prostate biopsy have led to both a reduction in the proportion of men diagnosed with advanced disease and disease-specific mortality. The consequence of widespread PSA screening has been a dramatic increase in both the detection of low-risk disease and the proportion of men diagnosed with prostate cancer undergoing radical prostatectomy (RP) or radiation therapy (RT).² In many cases, the complications associated with treating low-risk disease by RP or RT outweigh the benefits.^3,4 Although active surveillance (AS) is an appealing alternative for managing low-risk disease, it potentially decreases long-term survival rates.⁵ Due to the unreliability of disease risk stratification at the time of diagnosis, 14% to 41% of men assigned to AS will cross over to RP or RT due to upgrading or upstaging.⁶There is increasing evidence that multiparametric magnetic resonance imaging (mpMRI) localizes the site(s) of clinically significant prostate cancer prior to prostate biopsy.⁷ These suspicious MRI focal abnormalities can be biopsied directly in the MRI unit or under transrectal ultrasound (TRUS) guidance using software that co-registers and fuses the MRI and ultrasound (US) images.⁸ In many cases, MRI image-guided biopsy identifies a single clinically significant cancer. Although prostate cancer is typically a multifocal disease, the index, or dominant, lesion is typically predictive of extraprostatic extension and disease progression.^9–11 The majority of the secondary tumor sites are composed of small Gleason 6 disease, which represent no immediate threat.¹² It is theoretically possible to focally ablate only the index lesion, thereby achieving oncologic control while minimizing treatment-related morbidity by minimizing collateral damage to adjacent structures.Focal ablation of prostate cancer is an evolving treatment strategy that destroys a predefined region (or target) of the prostate that harbors the clinically significant cancer. A number of energy sources have been investigated for focal ablation of the prostate, including cryotherapy,¹³ high-intensity focused ultrasound (HIFU),¹⁴ photodynamic therapy,¹⁵ and laser ablation.¹⁶ Although long-term oncologic control has yet to be demonstrated, all of these targeted ablative options are associated with marked decrease in treatment-related complications. One of the advantages of laser technology is that the ablation can be performed with real-time MRI imaging. Because the target lesion are almost always defined by the MRI, laser ablation is currently the most accurate way to deliver ablative energy to the intended target. Other advantages of laser ablation include its homogeneous tissue necrosis, relatively low cost, and wide availability.¹⁷ MRI-guided focal ablation allows treatment monitoring using MR thermometry and real-time visualization of the targeted treatment zone.^18,19This review presents the principles of laser ablation, the role of mpMRI for delineating the site of significant prostate cancer, a summary of published clinical studies and the New York University Langone Medical Center (NYULMC)/Sperling Prostate Cancer Center experience on focal laser ablation of prostate cancer, criteria for selecting candidates for focal prostate ablation, and speculation regarding future directions of focal laser ablation for the treatment of localized prostate cancer.     

Bladder Cancer After Radiotherapy for Prostate Cancer

External beam radiotherapy (EBRT) is frequently used in the management of prostate cancer (PCa) as definitive, postoperative, or salvage local treatment. Although EBRT plays a central role in the management of PCa, complications remain a troubling by-product. Several studies have demonstrated an association between radiotherapy and elevated risk of acute and late toxicities. A secondary malignancy induced by initial therapy represents one of the most serious complications related to definitive cancer treatment. The radiation-related secondary primary malignancy risk increases with increasing survival time. Transitional cell carcinoma of the bladder is the most frequent secondary primary malignancy occurring after radiotherapy and is described as more aggressive; it may be diagnosed later because some radiation oncologists believe that the hematuria that occurs after prostate EBRT is normal. Some patients treated for localized PCa will subsequently develop invasive bladder cancer requiring surgical intervention. Patients with PCa treated with EBRT should be monitored closely for the presence of bladder cancer.Key words: Bladder cancer, Prostate cancer, Radiotherapy, External beam radiotherapyThe phenomenon of radiation-inducing the carcinogenesis has been well described in literature for decades. The correlation between ionizing radiation and DNA damage has been discussed in several studies.^1–4 Most of these studies evaluated the growth of solid tumors in a large population exposed to moderate to heavy doses of radiation, such as factory workers, patients exposed to a large number of diagnostic radiographic studies, and survivors of atomic and nuclear explosions. ¹ The casual effects of radiation exposure with subsequent mutagenesis are quite clear, shown both in vivo and in vitro.² Previous radiotherapy (RT) for prostate cancer (PCa) may play an important role in the development of secondary primary bladder cancer. This is a fairly uncommon event but a very real entity, of which both urologists and radiation oncologists need to be aware.     

Co-Occurring Gland Angularity in Localized Subgraphs: Predicting Biochemical Recurrence in Intermediate-Risk Prostate Cancer Patients

Quantitative histomorphometry (QH) refers to the application of advanced computational image analysis to reproducibly describe disease appearance on digitized histopathology images. QH thus could serve as an important complementary tool for pathologists in interrogating and interpreting cancer morphology and malignancy. In the US, annually, over 60,000 prostate cancer patients undergo radical prostatectomy treatment. Around 10,000 of these men experience biochemical recurrence within 5 years of surgery, a marker for local or distant disease recurrence. The ability to predict the risk of biochemical recurrence soon after surgery could allow for adjuvant therapies to be prescribed as necessary to improve long term treatment outcomes. The underlying hypothesis with our approach, co-occurring gland angularity (CGA), is that in benign or less aggressive prostate cancer, gland orientations within local neighborhoods are similar to each other but are more chaotically arranged in aggressive disease. By modeling the extent of the disorder, we can differentiate surgically removed prostate tissue sections from (a) benign and malignant regions and (b) more and less aggressive prostate cancer. For a cohort of 40 intermediate-risk (mostly Gleason sum 7) surgically cured prostate cancer patients where half suffered biochemical recurrence, the CGA features were able to predict biochemical recurrence with 73% accuracy. Additionally, for 80 regions of interest chosen from the 40 studies, corresponding to both normal and cancerous cases, the CGA features yielded a 99% accuracy. CGAs were shown to be statistically signicantly () better at predicting BCR compared to state-of-the-art QH methods and postoperative prostate cancer nomograms.     

Pathological Features of Localized Prostate Cancer in China: A Contemporary Analysis of Radical Prostatectomy Specimens

There has been a rapid increase in the incidence of prostate cancer in China, especially in areas with boosted economic development. In this study, we analyzed the pathological features of a contemporary series of radical prostatectomy cases. A total of 230 consecutive, whole-mounted radical prostatectomy specimens collected from 2012 to 2014 were reviewed. The median age of the patients was 68 years, and 64.3% of patients presented with prostate specific antigen alone. Pathological examination indicated that a high proportion (77.4%) of patients had intermediate- or high-risk disease according to the Cancer of the Prostate Risk Assessment Post-Surgical score. After surgery, only 28 patients met the criteria for active surveillance (organ-confined Gleason ≥6 disease). The Prostate Cancer Research International Active Surveillance criteria achieved a sensitivity of 57.1% and a specificity of 98.0% for identifying candidates. The probability of Gleason score upgrading was 24.8% in the entire group and 59.0% in biopsy-confirmed Gleason ≥6 disease. The predominant tumor was located in the transition zone in 14.8% of cases, while only three patients (1.3%) had a predominant tumor located in the anterior region. Patients with transition zone-predominant tumor were likely to have been referred with urinary symptoms and high prostate specific antigen levels. The results of this study highlight the contemporary pathological features of localized prostate cancer in urban China. There was an increased trend towards asymptomatic cases, though most patients had intermediate- or high-risk disease and were suitable for definitive treatment. The low prevalence of dominant cancer in the anterior region may reflect race-based pathological differences.     

Prognostic Value of Neutrophil-to-Lymphocyte Ratio in Localized and Advanced Prostate Cancer: A Systematic Review and Meta-Analysis

MethodsWe performed a meta-analysis to determine the predictive value of NLR for overall survival (OS), recurrence-free survival (RFS), and clinical features in patients with PCa. We systematically searched PubMed, ISI Web of Science, and Embase for relevant studies published up to October 2015.ResultsA total of 9418 patients from 18 studies were included in the meta-analysis. Elevated pretreatment NLR predicted poor OS (HR 1.628, 95% CI 1.410–1.879) and RFS (HR 1.357, 95% CI 1.126–1.636) in all patients with PCa. However, NLR was insignificantly associated with OS in the subgroup of patients with localized PCa (HR 1.439, 95% CI 0.753–2.75). Increased NLR was also significantly correlated with lymph node involvement (OR 1.616, 95% CI 1.167–2.239) but not with pathological stage (OR 0.827, 95% CI 0.637–1.074) or Gleason score (OR 0.761, 95% CI 0.555–1.044).ConclusionsThe present meta-analysis indicated that NLR could predict the prognosis for patients with locally advanced or castration-resistant PCa. Patients with higher NLR are more likely to have poorer prognosis than those with lower NLR.     

Multifunctional Nanoparticles for Prostate Cancer Therapy

The relapse of cancer after first line therapy with anticancer agents is a common occurrence. This recurrence is believed to be due to the presence of a subpopulation of cells called cancer stem cells in the tumor. Therefore, a combination therapy which is susceptible to both types of cells is desirable. Delivery of this combinatorial approach in a nanoparticulate system will provide even a better therapeutic outcome in tumor targeting. The objective of this study was to develop and characterize nanoparticulate system containing two anticancer agents (cyclopamine and paclitaxel) having different susceptibilities toward cancer cells. Both drugs were entrapped in glyceryl monooleate (GMO)-chitosan solid lipid as well as poly(glycolic-lactic) acid (PLGA) nanoparticles. The cytotoxicity studies were performed on DU145, DU145 TXR, and Wi26 A4 cells. The particle size of drug-loaded GMO-chitosan nanoparticles was 278.4 ± 16.4 nm with a positive zeta potential. However, the PLGA particles were 234.5 ± 6.8 nm in size with a negative zeta potential. Thermal analyses of both nanoparticles revealed that the drugs were present in noncrystalline state in the matrix. A sustained in vitro release was observed for both the drugs in these nanoparticles. PLGA blank particles showed no cytotoxicity in all the cell lines tested, whereas GMO-chitosan blank particles showed substantial cytotoxicity. The types of polymer used for the preparation of nanoparticles played a major role and affected the in vitro release, cytotoxicity, and uptake of nanoparticles in the all the cell lines tested.KEY WORDS: cancer stem cells, cyclopamine, glyceryl monooleate, nanoparticles, PLGA     

Therapeutic Strategies for Localized Prostate Cancer II: Perineal Prostatectomy, X-Rays, Protons, Neutrons, and Combination Brachytherapy

Application of improved imaging, diagnostic, and computer techniques is beginning to have an impact on the management of localized prostate cancer. It is possible to perform a range of surgical and radiation procedures with less morbidity than in the past. The changes in therapy for patients with localized disease derive from better knowledge of anatomy for invasive procedures and optimization of virtual planning for noninvasive methods. Perineal prostatectomy and combinations of beam and seed radiation offer both patient and physician reasonable therapeutic options.     

Incidence of Second Malignancies for Prostate Cancer

Introduction

There is a need to assess risk of second primary cancers in prostate cancer (PCa) patients, especially since PCa treatment may be associated with increased risk of second primary tumours.

Methods

We calculated standardized incidence ratios (SIRs) for second primary tumours comparing men diagnosed with PCa between 1980 and 2010 in the Canton of Zurich, Switzerland (n = 20,559), and the general male population in the Canton.

Results

A total of 1,718 men developed a second primary tumour after PCa diagnosis, with lung and colon cancer being the most common (15 and 13% respectively). The SIR for overall second primary cancer was 1.11 (95%CI: 1.06–1.17). Site-specific SIRs varied from 1.19 (1.05–1.34) to 2.89 (2.62–4.77) for lung and thyroid cancer, respectively. When stratified by treatment, the highest SIR was observed for thyroid cancer (3.57 (1.30–7.76)) when undergoing surgery, whereas liver cancer was common when treated with radiotherapy (3.21 (1.54–5.90)) and kidney bladder was most prevalent for those on hormonal treatment (3.15 (1.93–4.87)). Stratification by time since PCa diagnosis showed a lower risk of cancer for men with PCa compared to the general population for the first four years, but then a steep increase in risk was observed.

Conclusion

In the Canton of Zurich, there was an increased risk of second primary cancers among men with PCa compared to the general population. Increased diagnostic activity after PCa diagnosis may partly explain increased risks within the first years of diagnosis, but time-stratified analyses indicated that increased risks remained and even increased over time.     

以前列腺干细胞抗原为靶点的前列腺癌免疫治疗研究进展

前列腺干细胞抗原(PSCA)为细胞膜表面抗原,在正常前列腺组织中低表达,在雄激素依赖性和非依赖性前列腺癌组织中高表达,有较高的组织特异性,是前列腺癌治疗的理想靶标,近年来以PSCA为靶点的前列腺癌治疗性疫苗的研究已成为热点。我们简要综述以PSCA为靶点治疗前列腺癌的研究进展。     

Evaluation of NUF2 and GMNN Expression in Prostate Cancer: Potential Biomarkers for Prostate Cancer Screening

Background:Prostate cancer (PC) is one of the most abundant cancers among men, and In Iran, has been responsible for 6% of all deaths from cancer in men. NUF2 and GMNN genes are considered as loci of susceptibility to tumorigenesis in humans. Alterations in expression of these genes have been reported in various malignancies. The aim of our study was to test whether different NUF2 and GMNN expression levels are associated with PC incidence and hence, might be considered as new molecular tools for PC screening.Methods:Biopsy samples from 40 PC patients and 41 healthy Iranian men were used to determine the relative gene expression. After RNA extraction and cDNA synthesis, samples were analyzed using TaqMan Quantitative Real time PCR. Patients’ background information, included smoking habits and family histories of PC, were recorded. Stages and grades of their PC were classified by the TNM tumor, node, metastasis (TMN) staging system based on standard guidelines.Results:NUF2 expression did not significantly differ between the groups, while GMNN expression was significantly greater in the PC specimens than in the controls.Conclusion:Regarding the significant role of GMNN in various tumor phenotypes, and its importance in PC progression, the alteration in GMNN expression in PC samples vs. controls indicate that the genetic profiling of this cancer might be considered to personalize therapy for each patient in the future.Key Words: Family history, Geminin (GMNN), Tumor staging, NUF2, Prostate cancer     

CD44 and PTGS2 Methylation are Independent Prognostic Markers for Biochemical Recurrence Among Prostate Cancer Patients with Clinically Localized Disease

Up to 30% of men with clinically localized disease who receive radical prostatectomy develop a biochemical recurrence. Gene methylation in tumor tissue may distinguish men with aggressive cancer. This study evaluated methylation of GSTP1, RARβ2, CD44 and PTGS2 with biochemical recurrence among 60 patients who underwent radical prostatectomy using logistic regression and Kaplan Meier time to event analysis. Methylation of GSTP1 and RARβ2 was not associated with recurrence, however, CD44 and PTGS2 methylation were significant predictors. In multivariate models adjusting for Gleason grade, methylation profile of CD44 and PTGS2 combined was an independent predictor of biochemical recurrence (associated with 9-fold increased risk). In addition, Kaplan Meier analysis showed CD44 and PTGS2 methylation was associated with shorter time to recurrence. CD44 and PTGS2 methylation may predict biochemical recurrence in prostate cancer patients undergoing radical prostatectomy and if validated in larger studies, may identify patients with aggressive cancer.     

Analysis of Prostate Deformation during a Course of Radiation Therapy for Prostate Cancer

Purpose

Accurate analysis of the correlation between deformation of the prostate and displacement of its center of gravity (CoG) is important for efficient radiation therapy for prostate cancer. In this study, we addressed this problem by introducing a new analysis approach.

Method

A planning computed tomography (CT) scan and 7 repeat cone-beam CT scans during the course of treatment were obtained for 19 prostate cancer patients who underwent three-dimensional conformal radiation therapy. A single observer contoured the prostate gland only. To evaluate the local deformation of the prostate, it was divided into 12 manually defined segments. Prostate deformation was calculated using in-house developed software. The correlation between the displacement of the CoG and the local deformation of the prostate was evaluated using multiple regression analysis.

Results

The mean value and standard deviation (SD) of the prostate deformation were 0.6 mm and 1.7 mm, respectively. For the majority of the patients, the local SD of the deformation was slightly lager in the superior and inferior segments. Multiple regression analysis revealed that the anterior-posterior displacement of the CoG of the prostate had a highly significant correlation with the deformations in the middle-anterior (p < 0.01) and middle-posterior (p < 0.01) segments of the prostate surface (R² = 0.84). However, there was no significant correlation between the displacement of the CoG and the deformation of the prostate surface in other segments.

Conclusion

Anterior-posterior displacement of the CoG of the prostate is highly correlated with deformation in its middle-anterior and posterior segments. In the radiation therapy for prostate cancer, it is necessary to optimize the internal margin for every position of the prostate measured using image-guided radiation therapy.