Improving the pathway for men with suspected prostate cancer.

Kelly Kusinski, Urology Advanced Nurse Practitioner, The Royal Wolverhampton NHS Trust (kelly.kusinski@nhs.net), runner-up in the Urology Nurse of the Year category in the BJN Awards 2021.

Health-Related Quality of Life and Its Associated Factors in Prostate Cancer Patients Who Receive Androgen Deprivation Therapy.

BACKGROUND: Presently, few studies have examined the impact of positive thinking on the HRQoL of prostate cancer patients who receive androgen deprivation therapy (ADT). OBJECTIVES: We explored the factors that affect health-related quality of life (HRQoL), particularly positive thinking, of prostate cancer patients who receive ADT. METHODS: A cross-sectional design was used. A total of 132 prostate cancer patients, drawn from outpatient clinics of 2 medical centers, who were receiving ADT were included. Structured questionnaires, including a basic information sheet, the Positive Thinking Scale, Social Support Scale, and Functional Assessment of Cancer Therapy-Prostate (FACT-P), were used for data collection. Statistical analysis was performed by using independent-sample t tests, one-way analysis of variance, Pearson correlation, and multiple regression. RESULTS: Prostate cancer patients who were receiving ADT were more likely to engage in positive thinking, which was correlated with better social/family well-being, emotional well-being, functional well-being, prostate cancer concern, and a higher score on the FACT-P. Improved self-reported health status was correlated better with all subdimensions of HRQoL and better scores on the FACT-P. Greater social support was correlated with high social/family well-being. CONCLUSIONS: Positive thinking, self-reported health status, and social support are important associated factors of HRQoL in prostate cancer patients who receive ADT. IMPLICATIONS FOR PRACTICE: Oncology nurses can improve HRQoL by improving positive thinking, self-reported health status, and social support of prostate cancer patients who receive ADT.

Early vs. Late Androgen Suppression Therapy for Advanced Prostate Cancer.

Editor's note: The mission of Cochrane Nursing is to provide an international evidence base for nurses involved in delivering, leading, or researching nursing care. Cochrane Corner provides summaries of recent systematic reviews from the Cochrane Library. For more information, see https://nursing.cochrane.org.

[Management of hormone deprivation therapies in prostate cancer: Role of the nurse]. / Hormonothérapie dans le cancer de la prostate : quel rôle pour l'IDE en 2020 ?

Hormone deprivation therapies play a key role in the treatment of prostate cancer. These treatments require standardized care and regular monitoring. The objective of this work was to review the different hormonal therapies available, their side effects and the role of a coordinating nurse in the management of these therapies. First generation hormone therapy is the standard treatment for metastatic prostate cancer. In the past years, second generation hormone therapies have been indicated in combination with first-generation hormone therapies at different stages of the disease. These molecules are responsible for several side effects that should be monitored and prevented. Thus, after an initial assessment, clinical and paraclinical follow-up are essential. Our center has set up monitoring by a coordinating nurse (IDEC) to optimize the education and follow-up of the patient, but also to provide psychosocial support adapted throughout the patient's care path under hormone therapy. This monitoring and information function by IDEC can be facilitated by new digital solutions.

Indications and Complications of Androgen Deprivation Therapy.

OBJECTIVE: To review the indications for and side effects of androgen deprivation therapy (ADT) in men affected by prostate cancer. DATA SOURCES: National guidelines, evidence-based summaries, peer-reviewed studies, and websites. CONCLUSION: Indications for ADT include men with (1) intermediate- to high-risk localised prostate cancer undergoing radiation therapy, (2) biochemical recurrence after radical prostatectomy treated with salvage radiation therapy, or (3) metastatic prostate cancer. Several forms of ADT are available. To support self-management, body weight, diet, physical activity, alcohol consumption, and smoking should be discussed during clinical consultations. Important side effects of ADT may include flare-up phenomena of GnRH analogues, local reactions at injection sites, cardiovascular events, bone loss/fractures, drug-drug interactions, urinary tract dysfunction, hot flashes, cognitive impairment, seizure falls, and liver impairment. IMPLICATIONS FOR NURSING PRACTICE: Nurses have a role in personalized cancer care and should be familiar with indications, side effects, and interventions to optimize quality of life for men affected by prostate cancer receiving ADT.

An Exploration of the Rs of Radiobiology in Prostate Cancer.

OBJECTIVES: To explore the four Rs of radiobiology (Repair, Reoxygenation, Reassortment, and Repopulation) as a means to understand the effects of ionising radiation on biological tissue and subsequently as the basis for conventional fractionated treatment schedules. These radiobiological principles will form a rationale for combined regimens in prostate cancer treatment involving androgen deprivation therapy and radiation therapy and the associated toxicities of this approach will be discussed. DATA SOURCES: Electronic databases including CINAHL, MEDLINE, Scopus, professional websites, books and grey literature were searched using Google Scholar. CONCLUSION: It is important for nurses to understand the four Rs of radiobiology to grasp the effects of ionising radiation on biological tissue as the basis for conventional fractionated treatment schedules in prostate cancer. Men can experience a sequalae of physical and psychological side effects of treatment that can negatively impact quality of life. IMPLICATIONS FOR NURSING PRACTICE: Men can experience a range of unmet supportive care needs particularly related to informational, sexual, and psychological needs. For men affected by prostate cancer opting for radiation therapy (+/-) androgen deprivation therapy, nurses should ask targeted questions based on the Common Terminology Criteria for Adverse Events related to urinary and bowel function, potency and fatigue, and sexual health. We also recommend the use of holistic needs assessments to tailor self-management care plans. Evidence-based self-management advice should be provided in response to each man's unique needs.

Improving Physical and Mental Health in Patients with Prostate Cancer Undergoing Androgen Deprivation Therapy: Strategies to Promote and Improve Physical Activity Quality and Quantity.

OBJECTIVE: Prostate cancer continues to be one of the highest-incident cancers among men. Reducing serum testosterone with androgen deprivation therapy (ADT) is a common effective treatment. While well-demonstrated for cancer suppression, there are numerous adverse effects caused by ADT that can contribute to short- and long-term prognosis. Increased levels of physical activity (PA) during treatment may reduce these side effects. However, uptake of PA is low. The purpose of this review is to identify and evaluate the current literature on strategies to promote and increase the levels of PA in patients with prostate cancer undergoing ADT. DATA SOURCES: Electronic databases including CINAHL, MEDLINE, PsychINFO, Scopus, and grey literature were searched using Google Scholar up until April 2020. CONCLUSION: At present the most appropriate modes and dosages of PA for specific ADT toxicities is not known. It is established that some PA in the form of exercise, whether aerobic or resistance, is better than being sedentary for improvements in physical health, but beyond this prescription specifics have not been established. Further research is required to understand the impact of PA on the mental and physical health of men with prostate cancer undergoing ADT. IMPLICATIONS FOR NURSING PRACTICE: Being physically active and avoiding sedentary behaviour is important for men with prostate cancer undergoing ADT, especially the implementation of strength training. PA in the form of exercise can assist in reducing the adverse physical side effects in the short- and long-term, with limited understanding of the effects on mental health. PA improves mental health outcomes across populations, which may also translate to men with prostate cancer, although further research is required. An important strategy to improve PA within the prostate cancer population is to provide an early referral to an exercise professional, such as an accredited exercise physiologist/clinical exercise physiologist or physical therapist/physiotherapist, and is supported by research as best practice for people affected by cancer undergoing active treatment.

PSMA PET Scan Era: A Changing Paradigm PSMA PET and Lymph Node Dissection for Prostate Cancer Management.

OBJECTIVES: Staging of extra-prostatic prostate cancer has traditionally been assessed by computerised tomography (CT), bone scan, and where indicated, pelvic lymph node dissection at the time of surgery. The advent of the prostate-specific membrane antigen (PSMA) positron emission tomography (PET) scan shows promise in improving the accuracy of preoperative staging of this cancer. The role of pelvic lymph node dissection and its associated morbidity will be examined. This article will review current literature assessing the current role of PSMA PET and lymph node dissection in the staging and treatment of prostate cancer. DATA SOURCES: Peer-reviewed literature and databases, including Medline and PubMed. CONCLUSIONS: PSMA PET/CT appears to be a promising and superior staging investigation that may replace bone scan and CT scan in guiding treatment decision-making. It has high specificity and positive predictive value, thus in patients with low-risk prostate cancer, unnecessary extended pelvic lymph node dissection (ePLND) may be avoided. It would also help detect lymph nodes in patients with intermediate- or high-risk prostate cancer where ePLND may be required. ePLND remains the gold standard in staging high-risk patients because the PSMA PET/CT scan may under-stage the cancer. IMPLICATION FOR NURSING PRACTICE: Given the increased utilisation of PSMA PET/CT scan as a primary staging investigation in clinical practice for prostate cancer and as an alternative to bone scan and CT scan, it is timely for prostate cancer specialist nurses to understand and recognise the specificity and sensitivity of PSMA PET/CT scans in prostate cancer staging. Because ePLND is the gold standard for staging high-risk disease, prostate cancer specialist nurses should be aware of the complications associated with pelvic lymph node dissection to optimise supportive care for men affected by complications from ePLND.

Nursing Implications of Recent Changes in Management Practices for Metastatic Prostate Cancer.

OBJECTIVE: Prostate cancer is one of the most common male cancers in the world and accounts for substantial morbidity, mortality, loss of disability-adjusted life-years, and financial burden to patients and to the community. Metastatic prostate cancer has been managed for over 70 years with androgen deprivation therapy, but further life-prolonging therapies were not available until 2004. Since then, drugs such as docetaxel, abiraterone, enzalutamide, cabazitaxel, radium-223 dichloride, and (not available in Australia) sipuleucel-T have all demonstrated efficacy in prolongation of survival in castrate-resistant prostate cancer, and improvement in cancer-related morbidity. DATA SOURCES: Peer-reviewed scientific publications, Australian Government agency reports, and expert opinion. CONCLUSION: More recently, several of these agents have been given earlier in the treatment course to the hormone-sensitive metastatic setting, with even greater benefits in survival. These treatments have come at a cost: a literal financial cost to the community, and often to the patients and their families; and financial costs to the community to supply the drugs to those who need them. They also carry non-financial costs, including side effects of treatment, exacerbation of other co-morbidities, metabolic and bone health challenges, and psychological and social stresses, including those associated with longer survival with metastatic cancer. IMPLICATIONS FOR NURSING PRACTICE: The role of the nurse in management of these issues has never been more important. Nurses are often uniquely placed to educate men with prostate cancer and their families, screen for and identify adverse effects of treatment, and provide education and support not otherwise available. Nurses are central to the streamline of care coordination within the multidisciplinary team and the holistic care journey for men and their partners through the health care system. This review discusses several of these aspects to inform practice.

Prostate Cancer Prehabilitation and the Importance of Multimodal Interventions for Person-centred Care and Recovery.

BACKGROUND: Prostate cancer is the second most commonly diagnosed cancer globally. Cancer prehabilitation is defined as a process on the continuum of care that occurs between the time of a cancer diagnosis and the beginning of acute treatment. This article will discuss the importance of prostate cancer prehabilitation interventions in optimising physical and psychological recovery to enhance person-centred care. DATA SOURCES: Electronic databases including CINAHL, MEDLINE, PsychINFO, Scopus, professional websites, and grey literature were searched using Google Scholar. CONCLUSION: Prehabilitation in cancer care aims to enhance perioperative care and recovery. An emerging field of research suggests that the preoperative period may be physically and psychologically salient to introduce modifiable self-management behaviours to optimise overall recovery. IMPLICATIONS FOR NURSING PRACTICE: Prostate cancer specialist nurses provide the hub of person-centred care across the entire cancer care continuum embedded within the multidisciplinary team. Individually tailored interventions such as exercise and pelvic floor muscle training programmes, nutritional advice, anxiety and depression reduction, and sexual well-being interventions should be considered in the prehabilitation phase of the cancer care continuum.

An exploration of the Role of the Prostate Cancer Specialist Nurse from Two International Perspectives.

OBJECTIVE: A diagnosis of prostate cancer is a major life-changing event that brings social, psychological, physical, financial, and spiritual challenges. In both the United Kingdom (UK) and Australia, prostate cancer specialist nurses (PCSNs) have a unique role in the care of men and their families. Prostate cancer specialist nursing roles are described from the UK and Australian perspective. DATA SOURCES: Government regulations, peer-reviewed journal articles, nursing society and government websites. CONCLUSION: Specialist nursing roles have developed within different frameworks and in response to very different political drivers in the UK and in Australia. An evidence base has developed demonstrating that PCSNs offer positive outcomes for men and their families. Despite some differences in the scope of international roles, there are common aspects. Both health care settings have challenges in terms of education, role definition, and capacity. Yet both PCSN roles have delivered innovative models of specialist care in terms of service delivery and patient support and education. IMPLICATIONS FOR NURSING PRACTICE: PCSNs have the potential to significantly decrease the burden on the public health system and influence change. For men with prostate cancer and their families, PCSNs can improve care through holistic nursing models focussing on what is important to individuals: support, education, management of side effects, rehabilitation, and by delivering and improving access to high-quality care.

Prostate cancer survivorship priorities for men and their partners: Delphi consensus from a nurse specialist cohort.

AIMS & OBJECTIVES: To describe the prostate cancer survivorship experience and priorities from the perspective of prostate cancer specialist nurses. BACKGROUND: Specialist nurses are providing long-term survivorship care to men and their partners however, few prostate cancer survivorship interventions are effective and priorities for nurse-led survivorship care are poorly understood. DESIGN: A three-round modified Delphi approach. METHODS: The study was conducted between 1 December 2018 and 28 February 2019 to develop a consensus view from an expert nurse cohort (43 prostate cancer specialist nurses: 90% response). First, participants described men's prostate cancer survivorship experience and priorities for improving care for men and partners. In subsequent rounds, participants identified key descriptors of the survivorship experience; rated priorities for importance and feasibility; and identified a top priority action for men and for partners. Thematic analysis and descriptive statistics were applied. Guidelines for Reporting Reliability and Agreement Studies informed the conduct of the study. RESULTS: Prostate cancer specialist nurses characterised the prostate cancer survivorship experience of men as under-resourced, disjointed and distressing. In all, 11 survivorship priorities for men and three for partners were identified within five broad areas: capacity building; care coordination; physical and psychosocial care; community awareness and early detection; and palliative care. However, feasibility for individual items was frequently described as low. CONCLUSION: Internationally, prostate cancer survivorship care for men and their partners requires urgent action to meet future need and address gaps in capacity and care coordination. Low feasibility of survivorship priorities may reflect translational challenges related to capacity. Prostate cancer survivorship care guidelines connected to practice priorities are urgently needed. RELEVANCE TO CLINICAL PRACTICE: These findings address key gaps in the evidence for developing national nurse-led prostate cancer survivorship priorities. These priorities can be used to inform survivorship guidelines including nursing care for men with prostate cancer and their partners.

A Patient Decision Aid for Men With Localized Prostate Cancer: A Comparative Case Study of Natural Implementation Approaches.

BACKGROUND: There are multiple options for men diagnosed with localized prostate cancer. Patient decision aids (PtDAs) help empower individuals and reduce unwarranted practice variation, but few are used in clinical practice. OBJECTIVE: We compared 2 programs implementing PtDAs for men with localized prostate cancer. METHODS: This was a comparative case study. Case 1 was a hospital prostate pathway and case 2 was a provincial prostate pathway with 2 locations (2a, 2b). Nurses provided the men with PtDAs and answered questions. Data sources were as follows: (a) 2 years administrative data for men with localized prostate cancer, (b) clinicians survey and interviews, and (c) patients/spouses interviews. Analysis was within and across cases. RESULTS: The PtDA was used with 23% of men in case 1 (95% confidence interval, 19.8%-26.1%) and 98% of men in case 2a (95% confidence interval, 96.5%-99.8%). The pathway was not implemented in case 2b. Men given the PtDA had positive experiences. Many clinicians supported the use of PtDAs, some adapted their discussions with patients, and others did not support the use of PtDAs. To increase use in case 1, participants identified needing a Canadian PtDA available electronically and endorsed by all clinicians. In case 2b, the provincial prostate pathway needed to be implemented. CONCLUSIONS: There was variable uptake of the PtDAs between the cases. Men who received the PtDA had positive outcomes. Several strategies were identified to increase or sustain PtDA use. IMPLICATIONS FOR PRACTICE: Nurses have a key role in supporting men making decisions about prostate cancer treatment by providing PtDAs, answering questions, and advocating for men's preferences.

Nurse-Led Supportive Care Intervention for Men With Advanced Prostate Cancer: Healthcare Professionals' Perspectives.

PURPOSE: To identify barriers and corresponding solutions for implementing a telephone-based, nurse-led supportive care intervention for men with advanced prostate cancer. PARTICIPANTS & SETTING: 21 healthcare professionals with an average 15.81 years of experience in diverse prostate cancer care settings. METHODOLOGIC APPROACH: Data from semistructured interviews were coded into the Theoretical Domains Framework and mapped to behavior change techniques (BCTs) to inform the development of an implementation schema. FINDINGS: Barriers included lack of knowledge about the effectiveness of survivorship interventions and how to deliver them, low referral rates to psychosocial oncology care, low help-seeking behavior among men with advanced prostate cancer, lack of care coordination skills, and inadequate service capacity. IMPLICATIONS FOR NURSING: Interprofessional support exists for a nurse-led supportive care intervention. Causes of low engagement with supportive care among men with advanced prostate cancer extend beyond gendered patterns of response.

The Scottish prostate cryotherapy service-the role of the clinical nurse specialist.

This article outlines the role of the clinical nurse specialist in establishing a Scotland-wide national designated service for prostate cryotherapy for patients with radiation-recurrent prostate cancer. The service was established in 2009 and provides prostate cryotherapy across Scotland. This article reviews and discusses the challenges involved in setting up a new service for tertiary treatment as well as highlighting the key achievements of the service. The challenges have included introducing the cryotherapy procedure in a safe and quality assured manner, developing and refining the referral process, educating both primary and secondary care teams on salvage prostate cryotherapy as a treatment modality and surgical procedure, as well as managing of complications following salvage prostate cryotherapy. The article also outlines the achievements of both the service and the treatment as well as how the service has developed since 2009.

Investigating the effect of a symposium on sexual health care in prostate cancer among Dutch healthcare professionals.

AIMS AND OBJECTIVES: To investigate whether a symposium aimed at healthcare professionals in the uro-oncological field changes knowledge, competence and general practice regarding sexual dysfunction after prostate cancer treatment. BACKGROUND: Sexual dysfunction is not frequently discussed by healthcare professionals; lack of knowledge and training are two of the most often reported barriers. Provision of additional training could improve knowledge, competence and general practice of healthcare professionals. DESIGN: Two questionnaires were used in this pre-post study to determine knowledge, competence and general practice at the time of the symposium and six months afterwards. METHODS: In order to perform repeated measures to analyse alterations among participating healthcare professionals (n = 55), the McNemar's test was used. A STROBE checklist was completed. RESULTS: Seventy-three per cent (n = 40) stated that not enough attention was paid to prostate cancer-related sexual dysfunction during their education. Nurses felt significantly less competent in discussing sexual function, advising on sexual dysfunction and actively inquiring sexual complaints compared to other healthcare professionals. After the symposium, sexual dysfunction was significantly more often discussed. No significant effects were found on knowledge on sexual dysfunction, knowledge on treatment of sexual dysfunction, competence in discussing sexual function, advising on sexual dysfunction, actively inquiring sexual complaints and rate of referral. Tools needed to address sexual dysfunction concerned written information materials (75.5%) and a website containing adequate information (56.6%). CONCLUSIONS: The symposium had no significant influence on knowledge, competence and rate of referral in men with sexual dysfunction after prostate cancer treatment. However, sexual dysfunction was more frequently discussed after the symposium, so increase of awareness of consequences of prostate cancer treatment was achieved. RELEVANCE TO CLINICAL PRACTICE: Consequences of prostate cancer treatment to sexual function should be taken in consideration in daily practice; written information materials and a website containing adequate information were indicated as valuable resources to address sexual dysfunction in routine consultations.

Development and validation of the Family Resilience (FaRE) Questionnaire: an observational study in Italy.

OBJECTIVE: Develop and validate an instrument to assess family resilience and, more specifically, the family dynamics and resources, estimating the adaptation flexibility to cancer disease. Cohesion, communication, coping style and relational style were considered as critical functional areas in the construction of the instrument. DESIGN: Two cross-sectional studies. Study 1: identification of factorial structure of the questionnaire in two samples with different cancer sites. Study 2: validation of the questionnaire in patients with cancer in two different phases of their therapeutic pathway. PARTICIPANTS AND SETTING: A total of 213 patients with a histologically confirmed non-metastatic breast or prostate cancer and 209 caregivers were recruited for the two studies from an oncological hospital in Italy. OUTCOME MEASURES: The Resilience Scale for Adults and the Family Resilience (FaRE) Questionnaire, developed by the researchers, were administered to all patients and caregivers who gave consent. RESULTS: In study 1, the 60-item version of the FaRE Questionnaire underwent discriminant and construct validity, internal consistency and factorial analysis. Comparisons between patient and caregiver populations showed that patients perceived higher levels of family resources (p=0.048) and that patients with prostate cancer perceived less social support compared with patients with breast cancer (p=0.002). Factor analysis demonstrated four domains: communication and cohesion, perceived social support, perceived family coping, and religiousness and spirituality. In study 2, the validity and factorial structure of the final scale, composed of 24 items, were confirmed. The Cronbach alpha of all subscales was above 82. Normative values for patients with breast cancer can provide indications of family resilience levels. CONCLUSIONS: Preliminary findings showed acceptable psychometric properties for the FaRE Questionnaire to evaluate family resilience in oncological patients and their caregivers. Further research should test its sensibility to change to assess its use as a psychoemotional monitoring tool and its validity in other medical contexts.

Prostate Cancer: How Nurse Practitioners Can Aid in Disease Diagnosis and Management.

Early diagnosis and management of prostate cancer is crucial to providing safe, high-quality care to patients. Understanding the complexities of the signs and symptoms of prostate cancer can help nurse practitioners (NPs) make timely decisions to assess a patient's complaints and consider differential diagnoses. Acting on diagnostics, NPs can guide patients through treatment strategies to ensure positive health outcomes.

Cáncer de próstata: conocimientos e interferencias en la promoción y prevención de la enfermedad / Câncer de próstata: conhecimentos e interferências na promoção e prevenção da doença / Prostate cancer: knowledge and interference in the promotion and prevention of the disease

El artículo objetivó describir la percepción de los hombres sobre el cáncer de próstata y los factores de prevención relacionados. Se trata de un estudio cualitativo del tipo de ensayo comunitario. Se realizaron tres reuniones en forma de grupo focal, compuesto por 60 hombres con rango de edad superior a 40 años, abordando el tema del cáncer de próstata. Para el análisis de los datos cualitativos se realizó el análisis de contenido temático y los datos fueron organizados en el software - Atlas Ti. Los resultados fueron referenciados en los objetivos de este estudio y enfatizados en categorías. Los datos evidenciaron que todavía hay una barrera física y social a ser superada ante los estigmas masculinos, y existe una carencia de conocimiento sobre la prevención de este cáncer. El aumento de la oferta de exámenes diagnósticos, agilidad en la atención, horarios diferenciados para los trabajadores son algunas de las estrategias eficientes para atraer a esta población para la prevención del cáncer de próstata

O artigo objetivou descrever a percepção dos homens sobre o câncer de próstata e os fatores de prevenção relacionados. Trata-se de um estudo qualitativo do tipo ensaio comunitário. Foram realizadas três reuniões em forma de grupo focal, composto por 60 homens com faixa etária superior a 40 anos, abordando o tema do câncer de próstata. Para a análise dos dados qualitativos foi realizada a análise de conteúdo temática e os dados foram organizados no software - Atlas Ti. Os resultados foram referenciados nos objetivos deste estudo e enfatizados em categorias. Os dados evidenciaram que ainda há uma barreira física e social a ser ultrapassada diante dos estigmas masculinos, e existe uma carência de conhecimento sobre a prevenção deste câncer. O aumento da oferta de exames diagnósticos, agilidade no atendimento, horários diferenciados para os trabalhadores são algumas das estratégias eficientes para atrair esta população para a prevenção do câncer de próstata

The article aimed to describe the men's perception about prostate cancer and related prevention factors. This is a qualitative community trial type study. Three meetings were held in the form of a focus group, composed of 60 men aged over 40 years old, addressing the topic of prostate cancer. In order to analyze the qualitative data, thematic content analysis was performed and the data were organized in the software - Atlas Ti. The results were referenced in the objectives of this study and emphasized into categories. The data showed that there is still a physical and social barrier to overcome with male stigmas, and there is a lack of knowledge about the prevention of this cancer. The increase in the availability of diagnostic tests, agility in care, and differentiated schedules for workers are some of the efficient strategies to attract this population to the prevention of prostate cancer