Metastatic prostate cancer: complications and treatment

Diagnosis of advanced prostate cancer at the community level in Rwanda

BACKGROUND

Prostate cancer is the second most common cancer in men and sixth leading cause of mortality. If not recognized early, patients with advanced prostate cancer can experience debilitating complications which can otherwise be prevented by early androgen deprivation therapy. This research intends to define clear diagnostic tools that will guide practitioners in the rural community setting toward early management of advanced prostate cancer.

METHODS

We conducted a cross-sectional observational study at three referral hospitals in Kigali, Rwanda on patients who presented with clinical suspicion of advanced prostate cancer over a period of 6 months. All patients underwent prostate biopsy as well as metastatic work up (CT or MRI), for those who were eligible. Statistical analysis was done using STATA 14.2.

RESULTS

114 patients were included in the study. The median age was 70 years (interquartile range: 65-79 years). In total 14 (12.3%) patients were found to have benign disease, while 100 (87.7%) patients were found to have cancer. Among those who had cancer, 85 (85%) had advanced prostate cancer. 110/114 (96.5%) were symptomatic at presentation. Common presenting symptoms were lower urinary tract symptoms (80.7%), back pain (54.4%), and urinary retention (36.8%). Abnormal digital rectal examination (DRE) was a strong risk factor for both cancer and advanced disease. Prostate cancer was found in 92.2% of those with abnormal DRE compared to 41.7% in those with normal DRE (p = 0.001). Also, cancer was found in 96.1% of those with multinodular prostate on DRE (p = 0.02) and had high odds (OR 14.6; CI 3.41-62.25) of having advanced prostate cancer (p < 0.001). The mean (± SD) PSA was 643.3 ± 1829.8 ng/ml and the median (range) was 100 ng/ml (9.05-10,000 ng/ml) for the whole study population. All patients with prostatic-specific antigen (PSA) of 100 ng/ml or above had advanced prostate cancer.

CONCLUSION

The results show that there is a significant correlation between clinical findings and advanced prostate cancer. All patients with abnormal DRE and PSA above 100 ng/ml had advanced prostate cancer. Diagnosis of advanced prostate cancer is possible at the community level if PSA testing is utilized and practitioners are well trained.

Prostate-specific membrane antigen radioligand therapy of prostate cancer

Defining an optimal therapeutic approach in metastatic castration-resistance prostate cancer (mCRPC) patients in advanced stages is still challenging in routine clinical practice. Prostate-specific membrane antigen (PSMA) targeted radionuclide therapy with β- or α-emitters such as 177-Lutethium (177Lu) or 225-Actinium (225A) has been a main focus at multiple academic research centers in the last few years. This review article provides an overview of PSMA characteristics, clinical performance, safety and toxicity of PSMA targeted β- or α-radiation therapy.

Non-Coding RNAs in Castration-Resistant Prostate Cancer: Regulation of Androgen Receptor Signaling and Cancer Metabolism

Hormone-refractory prostate cancer frequently relapses from therapy and inevitably progresses to a bone-metastatic status with no cure. Understanding of the molecular mechanisms conferring resistance to androgen deprivation therapy has the potential to lead to the discovery of novel therapeutic targets for type of prostate cancer with poor prognosis. Progression to castration-resistant prostate cancer (CRPC) is characterized by aberrant androgen receptor (AR) expression and persistent AR signaling activity. Alterations in metabolic activity regulated by oncogenic pathways, such as c-Myc, were found to promote prostate cancer growth during the development of CRPC. Non-coding RNAs represent a diverse family of regulatory transcripts that drive tumorigenesis of prostate cancer and various other cancers by their hyperactivity or diminished function. A number of studies have examined differentially expressed non-coding RNAs in each stage of prostate cancer. Herein, we highlight the emerging impacts of microRNAs and long non-coding RNAs linked to reactivation of the AR signaling axis and reprogramming of the cellular metabolism in prostate cancer. The translational implications of non-coding RNA research for developing new biomarkers and therapeutic strategies for CRPC are also discussed.

Targeting L1 cell adhesion molecule expression using liposome-encapsulated siRNA suppresses prostate cancer bone metastasis and growth

The L1 cell adhesion molecule (L1CAM) has been implicated in tumor progression of many types of cancers, but its role in prostate cancer and its application in targeted gene therapy have not been investigated. Herein, we demonstrated that the L1CAM was expressed in androgen-insensitive and highly metastatic human prostate cancer cell lines. The correlation between L1CAM expression and prostate cancer metastasis was also validated in serum samples of prostate cancer patients. Knockdown of L1CAM expression in prostate cancer cells by RNA interference significantly decreased their aggressive behaviors, including colony formation, migration and invasion in vitro, and tumor formation in a metastatic murine model. These anti-malignant phenotypes of L1CAM-knockdown cancer cells were accompanied by G0/G1 cell cycle arrest and suppression of matrix metalloproteinase (MMP)-2 and MMP-9 expression and nuclear factor NF-κB activation. In vivo targeting of L1CAM expression using liposome-encapsulated L1CAM siRNAs effectively inhibited prostate cancer growth in mouse bone, which was associated with decreased L1CAM expression and cell proliferation by tumor cells. These results provide the first evidence for L1CAM being a major contributor to prostate cancer metastasis and translational application of siRNA-based L1CAM-targeted therapy.

A literature review of 18F-fluoride PET/CT and 18F-choline or 11C-choline PET/CT for detection of bone metastases in patients with prostate cancer

Although the detection of early bone metastases in men with prostate cancer remains a challenge in today's medicine, current guidelines state that bone scintigraphy with Tc-phosphonates (Tc-BS) is the most sensitive method for assessing bone metastases in these patients. In general, it is stated that bone scintigraphy has reasonable sensitivity and low specificity. The aim of this study was to present a review of the contemporary literature on the performance of F-fluoride and C-choline or F-choline and to reconsider the arguments based on which the present European and US guidelines are founded. A literature search was conducted using the Medline database. Data were taken from eligible studies and the level of evidence was scored. Data were pooled to calculate the weighted sensitivity and specificity. Thirteen studies were eligible for inclusion in this review. On a lesion basis, we found a sensitivity and specificity of 84.0 and 97.7% for C-choline and F-choline and 88.6 and 90.7% for F-fluoride, respectively. On a patient basis, the sensitivity and specificity were 85.2 and 96.5% for C-choline and F-choline and 86.9 and 79.9% for F-fluoride, respectively. No significant differences were found between the sensitivity and specificity of C-choline or F-choline and F-fluoride. There was large inconsistency in the reported sensitivity (range 39-100%) and specificity (range 57-80%) for Tc-BS. The literature provides evidence for superior detection of bone metastases by both F-fluoride PET and F-choline or C-choline PET with or without computed tomography (CT) compared with conventional Tc-BS. Guidelines should include F-fluoride PET/CT and C-choline or F-choline PET/CT as alternatives for Tc-BS for the detection of bone metastases in patients with prostate cancer.

A rat model of metastatic spinal cord compression using human prostate adenocarcinoma: histopathological and functional analysis

BACKGROUND CONTEXT

Cancer is a major global public health problem responsible for one in every four deaths in the United States. Prostate cancer alone accounts for 29% of all cancers in men and is the sixth leading cause of death in men. It is estimated that up to 30% of patients with cancer will develop metastatic disease, the spine being one of the most frequently affected sites in patients with prostate cancer.

PURPOSE

To study this condition in a preclinical setting, we have created a novel animal model of human metastatic prostate cancer to the spine and have characterized it histologically, functionally, and via bioluminescence imaging.

STUDY DESIGN

Translational science investigation of animal model of human prostate cancer in the spine.

METHODS

Luciferase-positive human prostate tumor cells PC3 (PC3-Luc) were injected in the flank of athymic male rats. PC3-Luc tumor samples were then implanted into the L5 vertebral body of male athymic rats (5 weeks old). Thirty-two rats were randomized into three surgical groups: experimental, control, and sham. Tumor growth was assessed qualitatively and noninvasively via bioluminescence emission, upon luciferin injection. To determine the functional impact of tumor growth in the spine, rats were evaluated for gait abnormalities during gait locomotion using video-assisted gait analysis. Rats were euthanized 22 days after tumor implantation, and spines were subjected to histopathological analyses.

RESULTS

Twenty days after tumor implantation, the tumor-implanted rats showed distinct signs of gait disturbances: dragging tail, right- or left-hind limb uncoordination, and absence of toe clearance during forward limb movement. At 20 days, all rats experienced tumor growth, evidenced by bioluminescent signal. Locomotion parameters negatively affected in tumor-implanted rats included stride length, velocity, and duration. At necropsy, all spines showed evidence of tumor growth, and the histological analysis found spinal cord compression and peritumoral osteoblastic reaction characteristic of bony prostate tumors. None of the rats in the sham or control groups demonstrated any evidence of bioluminescence signal or signs of gait disturbances.

CONCLUSIONS

In this project, we have developed a novel animal model of metastatic spine cancer using human prostate cancer cells. Tumor growth, evaluated via bioluminescence and corroborated by histopathological analyses, affected hind limb locomotion in ways that mimic motor deficits present in humans afflicted with metastatic spine disease. Our model represents a reliable method to evaluate the experimental therapeutic approaches of human tumors of the spine in animals. Gait locomotion and bioluminescence analyses can be used as surrogate noninvasive methods to evaluate tumor growth in this model.

Loss of let-7 microRNA upregulates IL-6 in bone marrow-derived mesenchymal stem cells triggering a reactive stromal response to prostate cancer

Bone marrow-derived mesenchymal stem cells (MSCs) are able to migrate to tumors, where they promote tumorigenesis and cancer metastasis. However, the molecular phenotype of the recruited MSCs at the tumor microenvironment and the genetic programs underlying their role in cancer progression remains largely unknown. By using a three-dimensional rotary wall vessel coculture system in which human MSCs were grown alone or in close contact with LNCaP, C4-2 or PC3 prostate cancer cell lines, we established invitro matched pairs of normal and cancer-associated MSC derivatives to study the stromal response of MSCs to prostate cancer. We observed that prostate cancer-associated MSCs acquired a higher potential for adipogenic differentiation and exhibited a stronger ability to promote prostate cancer cell migration and invasion compared with normal MSCs both in vitro and in experimental animal models. The enhanced adipogenesis and the pro-metastatic properties were conferred by the high levels of IL-6 secretion by cancer-associated MSCs and were reversible by functionally inhibiting of IL-6. We also found that IL-6 is a direct target gene for the let-7 microRNA, which was downregulated in cancer-associated MSCs. The overexpression of let-7 via the transfection of let-7 precursors decreased IL-6 expression and repressed the adipogenic potential and metastasis-promoting activity of cancer-associated MSCs, which was consistent with the inhibition of IL-6 3′UTR luciferase activity. Conversely, the treatment of normal MSCs with let-7 inhibitors resulted in effects similar to those seen with IL-6. Taken together, our data demonstrated that MSCs co-evolve with prostate cancer cells in the tumor microenvironment, and the downregulation of let-7 by cancer-associated MSCs upregulates IL-6 expression. This upregulation triggers adipogenesis and facilitates prostate cancer progression. These findings not only provide key insights into the molecular basis of tumor-stroma interactions but also pave the way for new treatments for metastatic prostate cancer.

In vivo targeting of ADAM9 gene expression using lentivirus-delivered shRNA suppresses prostate cancer growth by regulating REG4 dependent cell cycle progression

Cancer cells respond to stress by activating a variety of survival signaling pathways. A disintegrin and metalloproteinase (ADAM) 9 is upregulated during cancer progression and hormone therapy, functioning in part through an increase in reactive oxygen species. Here, we present in vitro and in vivo evidence that therapeutic targeting of ADAM9 gene expression by lentivirus-delivered small hairpin RNA (shRNA) significantly inhibited proliferation of human prostate cancer cell lines and blocked tumor growth in a murine model of prostate cancer bone metastasis. Cell cycle studies confirmed an increase in the G1-phase and decrease in the S-phase population of cancer cells under starvation stress conditions, which correlated with elevated intracellular superoxide levels. Microarray data showed significantly decreased levels of regenerating islet-derived family member 4 (REG4) expression in prostate cancer cells with knockdown of ADAM9 gene expression. This REG4 downregulation also resulted in induction of expression of p21^Cip1/WAF1, which negatively regulates cyclin D1 and blocks the G1/S transition. Our data reveal a novel molecular mechanism of ADAM9 in the regulation of prostate cancer cell proliferation, and suggests a combined modality of ADAM9 shRNA gene therapy and cytotoxic agents for hormone refractory and bone metastatic prostate cancer.

The supportive care needs of men with advanced prostate cancer

PURPOSE/OBJECTIVES

To better understand the priority supportive care needs of men with advanced prostate cancer.

RESEARCH APPROACH

Qualitative, descriptive study.

SETTING

Outpatient cancer center and urology clinics in central western Ontario, Canada.

PARTICIPANTS

12 men with hormone-sensitive prostate cancer and 17 men with hormone-refractory prostate cancer.

METHODOLOGIC APPROACH

Patients participated in focus groups and interviews that examined their supportive care needs, their priority needs, and suggestions for improvements to the delivery of care. Tape-recorded focus group discussions and interviews were organized using NVivo software.

MAIN RESEARCH VARIABLES

Patients' supportive care needs.

FINDINGS

Participants identified prostate cancer-specific information and support to maintain their ability "to do what they want to do" as priority needs. Both hormone-sensitive and hormone-refractory groups cited problems with urinary function, the side effects of treatment, fatigue, and sexual concerns as major functional issues. Participants experienced emotional distress related to diagnosis and treatment.

CONCLUSIONS

A priority health need for men with advanced prostate cancer is to improve or maintain functional abilities. In addition, men require support to meet their stage-specific information needs and to address concerns about the diagnosis and ambivalent feelings about past treatment decisions.

INTERPRETATION

Nurses could play an important role in addressing men's information needs and providing emotional support. The complex care needs of men with advanced prostate cancer provide opportunity for the development of advanced practice nurse roles that would use the clinical and nonclinical aspects of the role.

Occult prostate cancer detected by hyoid bone metastasis after resection of thyroglossal duct cyst

Metastatic carcinoma involving the hyoid bone has rarely been mentioned in the literature. The most frequent malignant lesion involving the hyoid bone metastasized from the larynx, followed by the vallecula and pyriform sinus. The authors report a unique case of occult prostate cancer that presented with an anterior midline neck mass diagnosed as a thyroglossal duct cyst. Two foci of metastatic carcinoma lesions in the hyoid bone were detected after Sistrunk's operation and occult prostate cancer was confirmed by immunohistochemical staining of prostate-specific antigen. Prostate cancer with metastasis to hyoid bone has not been described previously in the literature. The authors report this case which raises important pathological considerations for diagnosis. The unique presentation also reiterates the importance of prostate cancer bone metastasis.

Prostate cancer

Prostate cancer is biologically and clinically a heterogeneous disease and its imaging evaluation will need to be tailored to the specific phases of the disease in a patient-specific, risk-adapted manner. We first present a brief overview of the natural history of prostate cancer before discussing the role of various imaging tools, including opportunities and challenges, for different clinical phases of this common disease in men. We then review the preclinical and clinical evidence on the potential and emerging role of positron emission tomography with various radiotracers in the imaging evaluation of men with prostate cancer.

The Yin and Yang of bone morphogenetic proteins in cancer

Bone morphogenetic proteins (BMPs) were first studied as growth factors or morphogens of the transforming growth factor-beta superfamily. These growth molecules, originally associated with bone and cartilage development, are now known to play an important role in morphogenesis and homeostasis in many other tissues. More recently, significant contributions from BMPs, their receptors, and interacting molecules have been linked to carcinogenesis and tumor progression. On the other hand, BMPs can sometimes function as a tumor suppressor. Our report highlights these new roles in the pathogenesis of cancer that may suggest novel targets for therapeutic intervention.

Plasma osteopontin in comparison with bone markers as indicator of bone metastasis and survival outcome in patients with prostate cancer

BACKGROUND

The study was undertaken to evaluate the diagnostic and prognostic value of plasma osteopontin (OPN) in comparison to bone markers as well as the relationships between the markers and clinico-pathological factors in prostate cancer (PCa) patients.

METHODS

OPN and the bone markers carboxyterminal-telopeptide of type I collagen, bone-specific alkaline phosphatase (bALP), and aminoterminal-propeptide of type I procollagen (PINP) were measured in 90 PCa patients with and without bone metastases, 35 patients with benign prostatic hyperplasia, and 29 healthy men.

RESULTS

OPN and bone markers were significantly elevated in patients with bone metastases compared to the other groups. Significant correlations were found between all four-bone markers (r(s) = 0.43-0.79, all P < 0.01). OPN correlated with tumor grade (r(s) = 0.23, P < 0.05). In receiver-operating characteristics (ROC) analyses, OPN and bone markers were effective in distinguishing PCa patients with and without bone metastases showing areas under the curve (AUC) between 0.80 and 0.88 (all P < 0.001). OPN had an AUC of 0.85 that increased in combination with bALP up to 0.93 providing at the point with the highest diagnostic accuracy both a sensitivity and specificity of about 90%. Kaplan-Meier analyses and Cox proportional hazards regression models showed decreased survival of patients with high OPN and bone marker levels, while only high OPN and PINP were independent negative prognostic factors for PCa-related death.

CONCLUSIONS

OPN alone or in combination with bone markers is useful as diagnostic marker in the detection of bone metastases and as prognosticator in the survival prediction in PCa patients.

Androgen decreases osteoprotegerin expression in prostate cancer cells

Osteoprotegerin (OPG), a key regulator of bone resorption, is hypothesized to have a role in prostate cancer (CaP) bone metastasis. As advanced CaP is treated by androgen ablation, we examined if androgen modulates OPG expression by CaP cell lines in vitro. Basal levels of secreted OPG protein were significantly greater in androgen-independent PC-3 cells compared with androgen-responsive LNCaP-FGC cells (P<0.001); OPG was not detected in the androgen-responsive CaP cell lines LAPC-4 or DuCaP. Treatment with 5alpha-dihydrotestosterone (5alpha-DHT) significantly decreased OPG protein levels in both PC-3 and LNCaP-FGC, with maximal suppression using 10(-9)-10(-7) M 5alpha-DHT in PC-3 (P<0.01; day 3), and using 10(-10)-10(-9) M 5alpha-DHT in LNCaP-FGC cells (P<0.01; day 6). OPG messenger RNA levels were not significantly altered by this 5alpha-DHT treatment. Co-treatment with 10(-6) M flutamide blocked 5alpha-DHT inhibition of OPG protein expression in LNCaP-FGC cells. These data suggest that androgen may modulate OPG protein levels in CaP cell lines in vitro using a post-transcriptional mechanism.

Treatment decision making in prostate cancer: patients' participation in complex decisions

OBJECTIVE

(1) To explore to what degree prostate cancer (PC) patients felt they had participated in treatment decision making (TDM). (2) To determine whether perceived roles during TDM were associated with medical and sociodemographic variables. (3) To examine to what extent satisfaction with TDM was related to perceived role or medical and sociodemographic variables.

METHODS

Patients (n=126) were recruited in hospitals and from the Dutch PC patient organization. The relationship between patients' role and stage of disease, treatment modality, age, social status and education was determined, as well as patients' satisfaction with TDM.

RESULTS

Most patients felt they had participated in TDM (autonomous 18%, collaborative 60%). Older patients and those with advanced disease more frequently reported not having been involved in decision making. Satisfaction with TDM was related to age and role in TDM but not to stage of disease or treatment modality. Younger men were least content when they had not been involved in decision making.

CONCLUSION

Patients' level of participation and satisfaction with TDM appears to be related to medical and sociodemographic variables.

PRACTICE IMPLICATIONS

Satisfaction with TDM may be related to patients' age and assumed role. It is recommended to take this into account when planning treatment for prostate cancer patients.

Bone-Directed Treatments for Prostate Cancer

Maintaining bone health in men who have advanced prostate cancer is an important goal of therapy. Low bone mass is prevalent in men who have prostate cancer, and long-term androgen deprivation therapy causes additional significant decreases in bone mineral density. The adverse effects of the disease and current treatment modalities on bone health are further compounded when patients develop bone metastases,which cause clinically significant skeletal morbidity. Treatment with bone-directed therapies, including intravenous bisphosphonates, radio-nuclides, and endothelin-1 antagonists, can provide palliative and therapeutic benefits for patients who have established bone metastases, and treatment with intravenous bisphosphonates may prevent the development of bone metastases.

Serum Amino-Terminal Propeptide of Type 1 Procollagen (P1NP) in Prostate Cancer: A Potential Predictor of Bone Metastases and Prognosticator for Disease Progression and Survival

INTRODUCTION

To determine if amino-terminal propeptide of type 1 procollagen (P1NP) is reliable as a predictor of prostate cancer bone metastases and assess its value as a prognostic indicator of disease progression and survival.

MATERIALS AND METHODS

A cohort of patients with prostate cancer between January 1999 and July 2001 were recruited. Prostate-specific antigen (PSA) and P1NP levels were measured. Two years following completion of recruitment, patient notes were reviewed for symptoms of bone metastases and survival.

RESULTS

24 negative and 12 equivocal or positive bone scans were reported for 36 recruited patients. Mean PSA values for patients with negative, equivocal and positive scans were 18.3, 24.9 and 122.5 ng/ml while mean P1NP for the same groups were 38.2, 73.4 and 119.9 ng/ml. For patients with equivocal and positive scan, mean P1NP with and without bone symptoms were 111.5 and 65.7 ng/ml while for surviving and dead patients the values were 63.9 and 120.8 ng/ml, respectively.

CONCLUSIONS

Though this study involved a small number of patients, it demonstrates P1NP's potential as a predictor of bone metastases and a prognosticator for disease progression and survival.

Rationale for zoledronic acid therapy in men with hormone-sensitive prostate cancer with or without bone metastasis

Men with prostate cancer are at risk for bone loss and skeletal complications throughout the course of their disease. Bone loss is prevalent in many men with prostate cancer at initial diagnosis, and initiating androgen deprivation therapy results in accelerated bone resorption, leading to bone loss and an increased risk of fracture. These men are also at high risk for disease progression and bone metastases that can result in significant skeletal morbidity, including pathologic fracture, spinal cord compression, and debilitating bone pain requiring additional therapy. Excessive osteoclast activity plays a central role in the pathophysiology of bone disease at each stage of prostate cancer disease progression. Zoledronic acid, a highly potent inhibitor of osteoclast-mediated bone resorption, has increased bone mineral density in men receiving androgen deprivation therapy and is the only bisphosphonate that has shown statistically significant reductions in skeletal morbidity in patients with bone metastases from prostate cancer. Furthermore, preclinical evidence suggests that zoledronic acid has antitumor activity in prostate cancer models. Recently, a treatment algorithm was developed by the 3rd International Consultation on Prostate Cancer recommending the use of zoledronic acid for the prevention of skeletal complications in patients with bone metastases from prostate cancer, regardless of their hormone status, and for the prevention of treatment-induced bone loss in patients without evidence of bone metastases. According to this algorithm, zoledronic acid should be considered for the prevention of skeletal morbidity in patients with prostate cancer throughout their treatment continuum.