Human Intervention Studies And Epidemiologic Research

Published Date: 02 Nov 2017

Recent studies provide ample information regarding the exceeding toxic levels in the plant resources. In view of recent phytochemical studies, it has been pointed out that such substances included in vegetables and fruits could affect the efficacy of anti-cancer drugs and their metabolism [27], because many of the patients with cancer take folk medicines and supplements in addition to anti-cancer drugs.

The main reason we also consider the animal resources in cancer treatment is that recently, many cases were reported that the toxicity in plants and their derivatives are increasing due to high usage of pesticides and other chemicals.

The results of our nationally representative mortality survey confirm that cancer is an important cause of adult deaths in India, with more than 70% of fatal cancers occurring during the productive ages of 30–69 years. Contrary to the common perception that cancer kills urban and educated people, we noted that rates of cancer deaths were generally similar between rural and urban areas and about twice as high in the least versus the most educated.

Natural products isolated from various animals and plants have the ability to cure several disorders including cancer without any side effects. Recent investigations have been proved their significant role in treatment of cancer. This article presents an overview of anticancer properties of some anti-cancer animal venom and plants extracts. These natural analogs have considerable immunomodulatry and antioxidant activities leading to anticancer property. In conclusion this review delivers the knowledge about anticancer animal toxin and pharmaceutical plants of distant origin, which are used worldwide. It may be significant to exploit new anticancer medicines from natural resources.

Chemoprevention in combination with anticancer treatment represents an important approach to reduce morbidity and mortality from cancer. Natural compounds contain a large array of polyphenolic constituents that have been shown to block carcinogenesis and to inhibit the growth of tumors in whole animals, or in cell culture by altering the activity of certain enzymes or the expression of specific genes.

Chemoprevention can be applied in various stages that is generally referred as chemoprevention convergence plan:

Cancer research in general is carried out at three levels that includes Laboratory research,

Human intervention studies and Epidemiologic research. At each level the research is divided

into several phases/stages. The table below shows the various stages involved in Laboratory, Human intervention and epidemiologic research.

After phase I studies that evaluates clinical, laboratory and epidemiological findings, the phase II establishes effective dose and safety for humans. Here we summarized the dosages proposed in cancer treatment. Phase I1 human intervention studies, as shown in Figure 1, which involve small groups of subjects at each of several levels of intake for the intervention, determine the relationship between the dose for a chemoprevention agent and its potential adverse effects. The major endpoints are the determination of dose, safety, and toxicity. An acceptable dose may differ for various study populations depending on the risk of the cancer that one ultimately may be attempting to prevent. In a cancer treatment trial the maximum tolerated dose is used. However, as little or no toxicity is tolerated in a chemoprevention intervention, a lower, effective dose is required. That is, the dose level for a Phase I11chemoprevention human intervention study is chosen to strike a balance between the greatest likelihood of a preventive effect and a minimal level of adverse effects. The intervention plan specifies periodic monitoring for adverse effects and dose adjustments if adverse effects appear. Also specified are periodic monitoring of study endpoints, data analyses, and plans for stopping the trial if a preventive effect is seen, if adverse effects are unmanageable, or when the predetermined number of subjects have been observed for a specified period.

Along with the selection of dose, there are other differences between a standard clinical treatment trial and a trial for chemopreventive agents. For example, treatment trials are designed to treat existing disease. Prevention trials often are designed to effect changes at the subclinical or the molecular level. Thus, the study populations are quite different. A patient with disease is considered ill, whereas an individual at risk generally is considered healthy.

[Chemoprevention of Bladder Cancer, WINFRED F. MALONE]

Considering the chemopreventive effects of phytochemicals, they may depend on three main

activities: anti-oxidant, apoptosis inducing, and phase II enzymes inducing.

A diet rich in vegetable and fruit reduces the risk of cancer [2]. Polyphenols in these foods and

beverages are thought to be among the constituents responsible for the reduced cancer risk because they are protective in cell cultures and in animals pretreated with carcinogenic chemicals [3-9] or cancer cells [10]. Chemoprevention in combination with anticancer treatment represents an important approach to reduce morbidity and mortality from cancer. Carcinogenesis is generally recognized as a multi-step process in which distinct molecular and cellular alterations occur. From the studies of experimentally induced carcinogenesis in rodents, its development is considered to consist of several separate, but closely linked, stages — initiation, promotion and progression. And it takes many years to turn into complete malignancy. Therefore, there are ample opportunities to intervene in the development of cancer before the onset of malignancy.

Considering the chemo preventive effects of phytochemicals, they may depend on three main activities: anti-oxidant, apoptosis inducing, and phase II enzymes inducing.

Natural products such as green tea polyphenols, grape polyphenols, soy isoflavones, etc., are potent bioactive molecules that possess anti-carcinogenic activities. They interfere with the initiation, development and progression of cancer by the modulation of various mechanisms including cellular proliferation, differentiation, apoptosis, angiogenesis, and metastasis. Moreover, cancer cell lines and tumors appear to be more susceptible to the bioactivities of these natural compounds than normal cells.

A diet rich in vegetable and fruit reduces the risk of cancer [2]. Polyphenols in these foods and beverages are thought to be among the constituents responsible for the reduced cancer risk because they are protective in cell cultures and in animals pretreated with carcinogenic chemicals [3-9] or cancer cells [10]. Chemoprevention in combination with anticancer treatment represents an important approach to reduce morbidity and mortality from cancer. Red wines contain a large array of polyphenolic constituents that have been shown to block carcinogenesis and to inhibit the growth of tumors in whole animals, or in cell culture by altering the activity of certain enzymes or the expression of specific genes. In our study, occurrence of breast and thyroid multiple primaries was evaluated using data from the Connecticut Tumor Registry. A significantly elevated risk of thyroid cancer following breast cancer and breast cancer following thyroid cancer was demonstrated. This finding was even more notable when compared to the risks obtained for other sites. Recent studies provides ample information regarding the exceeding toxic levels in the plant resources In view of recent phytochemical studies, it has been pointed out that such substances included in vegetables and fruits could affect the efficacy of anti-cancer drugs and their metabolism [27], because many of the patients with cancer take folk medicines and supplements in addition to anti-cancer drugs.

The main reason we also consider the animal resources in cancer treatment is that recently, many cases were reported that the toxicity in plants and their derivatives are increasing due to high usage of pesticides and other chemicals

The results of our nationally representative mortality survey confirm that cancer is an important cause of adult deaths in India, with more than 70% of fatal cancers occurring during the productive ages of 30–69 years. Contrary to the common perception that cancer kills urban and educated people, we noted that rates of cancer deaths were generally similar between rural and urban areas and about twice as high in the least versus the most educated.

Natural products isolated from various animals and plants have the ability to cure several disorders including cancer without any side effects. Recent investigations have been proved their significant role in treatment of cancer. This article presents an overview of anticancer properties of some anti-cancer animal venom and plants extracts. These natural analogs have considerable immunomodulatry and antioxidant activities leading to anticancer property. In conclusion this review delivers the knowledge about anticancer animal toxin and pharmaceutical plants of distant origin, which are used worldwide. It may be significant to exploit new anticancer medicines from natural resources.

Conclusion:

It is an effort to summarize all what is known so far. This paper provides a collection of chemo preventive properties of natural substances, having less adverse effects. So that further comparative studies could be carried out in order to obtain a better drug against carcinoma.

It can serve as a repository for the scientific community working to develop new and improved medicines for cancer which poses serious threat to mankind all across the globe in the present scenario.

We are trying to emphasize on the significance of using naturally occurring constituents in cancer chemoprevention. Perhaps natural compounds may have slow but long and stable effect on cancer.