The antihormonal preventive therapy of breast cancer and prostate cancer (original) (raw)

Pharmacological prevention of breast cancer: Quo vadis?

The Breast, 2003

Although tamoxifen reduces breast cancer incidence by 30-40% in at-risk subjects, its adverse events may be a limiting factor. Thus, different strategies are being pursued to improve the risk:benefit ratio of breast cancer chemoprevention intervention. Firstly, raloxifene is being compared with tamoxifen in a phase-III trial, whereas the minimal active dose of tamoxifen is being assessed in phase I-II trials. The combination of HRT and tamoxifen may also reduce the risks while retaining the benefits of either agent. Anastrozole holds promise as a preventive agent based on preliminary data on contralateral breast cancer. Another important area is the appropriate identification of women at increased risk for ER-positive breast cancer due to reproductive factors, which may maximize the therapeutic index of hormonal agents. Finally, new targets that interfere with the onset of ER-negative breast cancer are being sought since one-third of breast cancers will not be modulated by hormonal interventions.

Preventive treatments for breast cancer: recent developments

Clinical and Translational Oncology, 2014

Breast cancer is a burden for western societies, and an increasing one in emerging economies, because of its high incidence and enormous psychological, social, sanitary and economic costs. However, breast cancer is a preventable disease in a significant proportion. Recent developments in the armamentarium of effective drugs for breast cancer prevention (namely exemestane and anastrozole), the new recommendation from the National Institute for Health and Care Excellence to use preventative drugs in women at high risk as well as updated Guidelines from the US Preventive Services Task Force and the American Society of Clinical Oncology should give renewed momentum to the pharmacological prevention of breast cancer. In this article we review recent major developments in the field and examine their ongoing repercussion for breast cancer prevention. As a practical example, the potential impact of preventive measures in Spain is evaluated and a course of practical actions is delineated.

Chemotherapeutic Prevention Studies of Prostate Cancer

Journal of Urology, 2004

Purpose: 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, ie the administration of agents that inhibit 1 or more steps in the natural history of prostate carcinogenesis. We review prostate cancer chemoprevention studies in Europe. Materials and Methods: Published studies were identified in a search of MEDLINE. Information about ongoing studies was provided by author access to protocols. Results: 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 5␣-reductase inhibitors, which inhibit the conversion of testosterone to the more potent androgen dihydrotestosterone. Conclusions: 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 2 studies, 1 examining the type 1 5␣-reductase selective inhibitor finasteride and the other using the dual 5␣-reductase inhibitor dutasteride, will determine the benefits of androgen inhibition strategies for prostate cancer chemoprevention.

Familiar drugs may prevent cancer

Postgraduate Medical Journal, 2001

Despite positive results in large scale chemoprevention trials, many physicians are unaware of the potential cancer preventive properties of drugs in common usage. The antioestrogen tamoxifen and the selective cyclo-oxygenase-2 inhibitor celecoxib have been licensed in the USA for the chemoprevention of breast and colorectal cancers respectively in selected high risk individuals. Similarly, folate and retinol have been shown to decrease the incidence of colorectal cancer and squamous cell carcinoma of the skin respectively in large scale intervention trials. Other retinoids have proved eYcacious in the tertiary chemoprevention of cancers of the breast and head/neck. Epidemiological evidence also exists in favour of aspirin, nonsteroidal anti-inflammatory drugs, and angiotensin converting enzyme inhibitors preventing certain cancers. Phytochemicals may represent less toxic alternatives to these agents. Although some of these drugs are available without prescription and most are not yet licensed for use in cancer chemoprevention, physicians and students of medicine should be aware of this accumulating evidence base. Practitioners should be amenable to patient referral to discuss complex issues such as risk estimation or potential benefit from intervention. (Postgrad Med J 2001;77:492-497)

Prevention of prostate cancer through custom tailoring of chemopreventive regimen

Chemico-Biological Interactions, 2008

One practical way to control cancer is through chemoprevention, which refers to the administration of synthetic or naturally occurring agents to block, reverse or delay the process of carcinogenesis. For a variety of reasons, the most important of which is human acceptance, for chemopreventive intervention naturally occurring diet-based agents are preferred over synthetic agents. For a long time, the prevailing mantra of cancer chemoprevention has been: "Find effective agents with acceptable or no toxicity and use them in preventing cancer in relatively healthy people or individuals at high risk for developing cancer". In pursuing this goal many naturally occurring phytochemicals capable of affording protection against carcinogenesis in preclinical settings in experimental animals have been described. However, clinical trials of single agents have yielded disappointing results. Since carcinogenesis is a multistage phenomenon in which many normal cellular pathways become aberrant, it is unlikely that one agent could prove effective in preventing cancer. This review underscores the need to build an armamentarium of naturally occurring chemopreventive substances that could prevent or slow down the development and progression of prostate cancer. Thus, the new effective approach for cancer prevention "building a customized mechanism-based chemoprevention cocktail of naturally occurring substances" is advocated.

Future possibilities in the prevention of breast cancer: breast cancer prevention trials

Breast cancer research : BCR, 2000

The available results from breast cancer chemoprevention trials are reviewed. Four trials using tamoxifen have been performed, of which three have reported efficacy results. A fifth trial using raloxifene has also been reported. The largest tamoxifen trial showed approximately 50% reduction in breast cancer incidence in the short term, but the two smaller trials did not find any reduction. Greater agreement exists for side effects; incidences of thromboembolic disease and endometrial cancers are raised approximately threefold when tamoxifen is used for 5 years. The possible reasons for the discrepancy in breast cancer reduction are explored. A review of trial parameters does not clearly explain this difference, and a meta-analysis indicates that all results are compatible with a 40% reduction in short-term incidence. Several important questions remain regarding the clinical implications of this result, including the effect on mortality, the appropriate risk groups for chemopreventio...

Anti-Tumor Therapies-Cases of Breast and Prostate Cancers

Journal of Tumor Medicine & Prevention, 2017

After a circuitous detour involving numerous and varied hypotheses as to the causes of cancer, and the associated developments in chemotherapy and synergy with other modalities (surgery, radiation), and with our deeper understanding of the biology of this disease, we have now come to the conclusion that cancer is braided into our genome. A cancer cell is an astonishing perversion of the normal cell in that both rely on growth in the most basic elemental sense, viz. the division of one cell to form two daughter cells. Whilst in a normal cell, division is regulated and growth stimulated by specific complementary triggering and arresting signals, a cancer cell grows and divides frenetically without a regulating mechanism-a clonal process. Cancer is more than a clonal disease, however, it is a clonally evolving disease. When mutating, it can resist attack by a chemotherapeutic drug or by the autoimmune system; generate new cells that are increasingly adapted to survival and growth, and even speed up other mutations. The fittest cancer cells survive-the ultimate product of Darwinian selection of the fittest. I will discuss the hallmarks of cancer and the principles of cancer therapy. I will recall the long history of breast cancer from ancient times to the present, and describe the various therapeutic modalities' principles, applications, evolution and synergy (surgery, radiation, chemotherapy, bone marrow transplantation) and the complementary therapies (adjuvant, hormone replacement treatment, and palliative) and the corresponding benefits. I will also discuss past clinical trials and their conclusions (or lack thereof) and remark on current tests administered for breast and prostate cancer. I will conclude with a critique of the test guidelines issued by various national and international regulatory bodies and professional societies, providing additional evidence that so-called "population medicine" (in this case, mass screening) disregards individual variability and promotes considerably more unnecessary medical testing and procedures.