前列腺癌的化学预防

前列腺癌是欧美国家重要的男性肿瘤,前列腺癌发病率在我国呈逐年上升趋势。通过对前列腺癌的预防必将对疾病相关的费用、发病率及死亡率等方面起到积极的作用。肿瘤的化学预防,即应用天然的、合成的或者生物化学因子逆转、抑制或阻止肿瘤进展为浸润性肿瘤。本文结合文献概述有关前列腺癌化学预防方面的进展。     

结直肠癌化学预防新进展

近年来肿瘤化学预防策略的研究取得了一定的进展。基于肿瘤发生是由正常细胞发展而来这一认识的逐渐深入,期望通过生活方式的调节、自然或人工合成的化学物质干预阻断甚至逆转这一过程。目前肠癌的化学预防策略取得了显著的成功,但是尚缺乏大规模的临床试验验证。本文综述了近年来阿司匹林、维生素D、熊去氧胆酸、肠道菌群、联合化学预防策略在结直肠癌化学预防中的作用及研究进展。基于个体化特点制定最小有效剂量、最短使用时间、更精确的高风险人群分类的化学预防方案,能够获取最好的风险效益比,增加公共预防和个体预防的社会和经济效益。     

化学和免疫药物灌注预防浅表性膀胱肿瘤复发的研究进展

化学和免疫药物灌注是预防浅表性膀胱肿瘤复发的手段，但就何种化学或免疫药物疗效较好，则一直存在争议，看法不一，本文对各种灌注药物的效果作了比较，得出了初步结论。     

食疗剂与前列腺癌化学预防

肿瘤的化学预防指应用天然的、合成的或者生物化学因子以降低肿瘤发病率或复发率、延缓肿瘤发生及发展.近年来,大量的研究表明绿茶、大豆、石榴等食物具有预防前列腺癌的作用,可能与这些食物中某些成分的抗氧化、诱导肿瘤细胞凋亡、阻滞肿瘤细胞周期等作用有关.一些大规模的食疗剂化学预防前列腺癌的临床试验已在进行之中,将为前列腺癌的化学预防提供更多选择,也使前列腺癌化学预防方案的个性化得以可能实现.     

溃疡性结肠炎相关结直肠癌和非典型增生的研究进展

长期溃疡性结肠炎病史者结直肠癌的发病率明显增加.目前已知的危险因素包括多年病史、广泛结肠受累、结肠炎症程度、结直肠癌家族史、合并原发性硬化性胆管炎等.发病的分子机制主要是染色体不稳定性和微卫星不稳定性.对多年病史者尤其是高危患者应行结肠镜筛查,同时应给予化学预防以减少肿瘤的发生.新的内镜技术提高了肿瘤检测的敏感性,为肿瘤筛查提供了更可靠的方法.     

前列腺癌的化学预防

癌症预防方式大致可以分为饮食预防、药物化学预防、生活方式预防以及手术预防几类。现今临床肿瘤预防的研究热点是化学预防,其主要的研究对像包括恶性肿瘤高危人群、癌前病变以及具有发     

溃疡性结肠炎相关结直肠癌和非典型增生的研究进展

长期溃疡性结肠炎病史者结直肠癌的发病率明显增加.目前已知的危险因素包括多年病史、广泛结肠受累、结肠炎症程度、结直肠癌家族史、合并原发性硬化性胆管炎等.发病的分子机制主要是染色体不稳定性和微卫星不稳定性.对多年病史者尤其是高危患者应行结肠镜筛查,同时应给予化学预防以减少肿瘤的发生.新的内镜技术提高了肿瘤检测的敏感性,为肿...     

乳腺癌的预防(编译)

重点复习乳腺癌的预防措施 ,包括化学药物预防 ,如三苯氧胺、Raloxifene、视黄醇、芳香酶抑制剂和灭活剂 ,手术预防和饮食调控等措施     

我国食管癌二级预防研究概况

食管癌是我国高发肿瘤之一,其预防方法主要有两种;一是病因学预防或称一级预防;二是发病学预防或称二级预防.二级预防主要内容是设法消除食管癌的发生条件或是在癌变过程中某一阶段设法阻断其发展.我国食管癌二级预防的主要研究内容是对食管癌前病变(食管上皮细胞重度增生简称重增)的阻断性治疗.这方面的工作国外研究者甚少,我国科学工作者在现场做了大量的工作,仅就近十多年的研究简介如下.     

肿瘤化疗后患者居家跌倒预防知信行现状及影响因素研究

目的 了解肿瘤化疗后患者居家跌倒预防知信行现况及其影响因素,为构建肿瘤化疗后患者居家跌倒预防策略提供参考.方法 使用自行设计的居家跌倒预防知信行问卷,便利选取350例肿瘤化疗后患者进行调查.结果 肿瘤化疗后患者居家跌倒预防知信行总分(62.86±15.13)分,知识、信念及行为维度得分分别为(60.84±17.52)分、(74.10±16.48)分、(57.62±15.13)分.多元线性逐步回归分析显示,文化程度、已完成化疗疗程、家庭人均月收入、医疗付费方式、家庭关怀度及医护人员是否对居家患者定期进行跌倒预防随访是肿瘤化疗后患者居家跌倒预防知信行得分的影响因素(P<0.05,P<0.01).结论 肿瘤化疗后患者居家跌倒预防态度较为积极,但相关知识欠缺,行为总体较差.需着重进行居家跌倒危险因素及跌倒后应对技能方面的知识教育,同时加强定期随访服务.     

Prostate cancer chemoprevention agents exhibit selective activity against early stage prostate cancer cells

Preclinical models for the identification of prostate cancer chemoprevention agents are lacking. Based upon the notion that clinically useful chemoprevention agents should exhibit selective activity against early stage disease, studies were undertaken to assess whether chemoprevention agents selectively inhibited the growth of early stage prostate cancer, as compared to late stage cancer. First, a series of cell and molecular studies were performed, which, when taken together, validated the use of a panel of prostate cell lines as a model of the different stages of carcinogenesis. Next, therapeutic responsiveness to ten different cytotoxic or chemoprevention agents was evaluated. Chemoprevention agents exhibited selective activity against normal and early transformed prostate tissue, whereas cytotoxic agents were non-specific. Selective activity against early versus advanced prostate cancer cells is identified as a potential screening method for chemoprevention agents.Prostate Cancer and Prostatic Diseases (2001) 4, 81-91     

Heart healthy equals prostate healthy equals statins: the next cancer chemoprevention trial. Part I

PURPOSE OF REVIEW: Several important observations should be kept in mind by cancer researchers: cardiovascular disease (CVD) is the number one cause of death; CVD is the number one cause of death in the largest cancer chemoprevention trials; CVD is the number one or two cause of death in prostate cancer patients; and some of the mechanisms that increase the risk of CVD may also increase the risk or progression of prostate cancer. RECENT FINDINGS: Screening studies suggest a high prevalence of dyslipidemia in men with and without prostate cancer. Numerous recent lifestyle interventions that reduce cholesterol have also been found to have a potential impact on reducing the risk of prostate cancer. Recent studies of statins and other heart healthy agents have found a secondary potential for exhibiting a reduced risk or progression of prostate cancer. SUMMARY: Laboratory and clinical data over the past several decades continue to support the use of a heart healthy agent in the nest cancer chemoprevention trial. The potential for an agent to simultaneously reduce the risk of the primary and secondary cause of death suggests that statins and other heart healthy agents are the ideal next interventions to be utilized in the next major cancer chemoprevention trial. If successful, this agent would most likely represent a dramatic impact on the history of cancer chemoprevention, and if not successful the potential secondary impact would again be a landmark finding in cancer chemoprevention; so the time is more than ripe for such a unique trial.     

Chemoprävention des Prostatakarzinoms

Despite advances in the detection and management of prostate cancer, this disease remains a major cause of morbidity and mortality in men. Increasing attention has focused on the role of chemoprevention for prostate cancer, i.e., the administration of agents that inhibit one or more steps in the natural course of prostate carcinogenesis. We review prostate cancer chemoprevention studies in Europe.Published studies were identified in a search of MEDLINE. Information about ongoing studies was provided by author access to protocols. A variety of chemoprevention studies have focused on the role of dietary factors, vitamins, and trace elements in prostate cancer. Some of these studies have been prospective, randomized, and double-blinded, while others have used retrospective or epidemiological approaches. Large-scale randomized studies are also evaluating the role of 5alpha-reductase inhibitors, which inhibit the conversion of testosterone to the more potent androgen dihydrotestosterone.Robust evidence is lacking for the value of chemopreventive agents in prostate cancer. Current evidence does suggest that vitamin E and selenium may have a role in prostate cancer chemoprevention. Data from two studies, one examining the type 1 5alpha-reductase selective inhibitor finasteride and the other using the dual 5a-reductase inhibitor dutasteride, will determine the benefits of androgen inhibition strategies for prostate cancer chemoprevention.     

What’s new in the field of prostate cancer chemoprevention?

Chemoprevention trials for several malignancies are completed, planned, or underway. Prostate cancer is one of the most common forms of cancer and understandably has received considerable recent attention as a potential target for chemoprevention. This article examines chemoprevention trials for prostate cancer, including the Prostate Cancer Prevention Trial, Selenium and Vitamin E Cancer Prevention Trial, and cyclooxygenase inhibitors in the prevention of prostate cancer.     

Towards Early and More Specific Diagnosis of Prostate Cancer? Identifying a Key Target Population for Chemoprevention and Available Strategies

ContextAnalysis of the Prostate Cancer Prevention Trial (PCPT) demonstrates that there is no longer a prostate-specific antigen (PSA) threshold below which prostate cancer cannot be found. Treatment with finasteride reduces the number of positive biopsies for prostate cancer, but its effect on tumour grading remains highly debatable, and there is some uncertainty regarding the value of routine use of finasteride as a chemoprevention therapy against prostate cancer and in men with symptomatic benign prostatic hyperplasia (BPH). This group is not the best target for chemoprevention due to the risk of overprevention and exposure to potential side-effects.ObjectiveAn ideal target for chemoprevention may, therefore, be patients with high-grade prostatic intraepithelial neoplasia (HG-PIN). The aim of this review is to determine the ideal target population for chemoprevention studies in premalignant and malignant prostate adenocarcinoma and to investigate available preventive therapies. A renewed interest in active surveillance in patients with localised prostate cancer has also highlighted the value of preventing the evolution/progression of an already-diagnosed tumour through either diet or medication.Evidence acquisitionSeveral randomised and nonrandomised clinical trials published in the academic literature that study various available chemoprevention strategies in men with prostatic intraepithelial neoplasia (PIN) and prostate cancer have been reviewed for this paper.Evidence synthesisA number of potential preventive agents have been investigated in patients with HG-PIN, including hormones (flutamide, finasteride, leuprolide acetate) and antioxidants such as lycopene, selenium, and catechins. One of the most promising chemoprevention drugs is the selective oestrogen receptor modulator toremifene citrate.ConclusionsA better target for chemoprevention may be men with HG-PIN who have a high risk of developing prostate cancer in later life. It may be worth monitoring young men with a high risk of developing HG-PIN in the future as potential targets for chemoprevention rather than focusing only on chemoprevention in the high-risk HG-PIN patient group.     

Chemoprevention of Nonmelanoma Skin Cancer with Systemic Retinoids: Practical Dosing and Management of Adverse Effects

BACKGROUND: In patients with nonmelanoma skin cancer that is high risk or characterized by numerous tumors, chemoprevention with systemic retinoids may effectively decrease the number of new tumors whereas the chemosuppressive effects may reduce the risk of recurrence or disease progression. A patient's intolerance of the mucocutaneous effects of retinoid therapy or abnormal laboratory findings may hamper continuous therapy. OBJECTIVE: To present a method for optimizing tolerance of systemic retinoids for chemoprevention and for monitoring and managing adverse events. METHODS: After reviewing the data on the use of systemic retinoids for chemoprevention, we developed a simplified approach for administering oral retinoids for chemoprevention of nonmelanoma skin cancer as well as basic guidelines for the prevention and management of adverse effects and appropriate laboratory monitoring. RESULTS: Chemoprevention with systemic retinoids in patients with a history of numerous tumors or high-risk skin cancer can be optimized with graduated dose escalation and preventive strategies for the most common adverse effects. Routine laboratory monitoring may assist in detecting adverse effects, which can be managed in most cases. CONCLUSION: In our experience, the effective use of systemic retinoids for chemoprevention of nonmelanoma skin cancer in high-risk patients can be optimized through a standardized, proactive approach.     

Can we prevent prostate cancer? Rationale and current status of prostate cancer chemoprevention

Prostate cancer has been one of the most frequent cancers among men in Western countries for the past decade. Investigation of prostate cancer prevention is very attractive, because prostate cancer has a high incidence, long-term natural history, regional difference in incidence, and is effected by sex steroids. Chemoprevention is defined as the use of specific agents to suppress or reverse carcinogenesis and to prevent the development of cancer. The development of chemoprevention strategies against prostate cancer would be of medical and economic importance. Basic and clinical research of chemoprevention of prostate cancer are under active investigation. This article aims to summarize and review the basic evidence and clinical trials on prostate cancer chemoprevention. Recent research has demonstrated that many agents, such as agents altering sex steroid signaling, drugs inducing antiproliferation/differentiation, retinoids, anti-inflammatory drugs, and antioxidants, could be potential preventatives for prostate cancer. Large-scale clinical trials have suggested that 5alpha-reductase inhibitor finasteride, selenium, and vitamin E can function as a chemopreventive agent. Although no definitely effective strategies of prostate cancer prevention have been identified yet, increasing evidence will provide effective and safe strategies that bring clinical benefits.