Cancer Epidemiology

Each year cancer is newly diagnosed in about 10 million of people worldwide, and it causes 5 million deaths. Cancer is second to cardiovascular disease as a cause of death in developed countries, and overall causes 10% of all deaths in the world. In most developed countries, one person in three will develop cancer during their lifetime, and this will increase to one in two by the year 2010 provided that the age of the population will increase as predicted.1'2

Cancer comprises over 200 distinct entities differing in their genetic basis, etiology, clinical characteristics, patterns of progression, and final outcome. In broad terms cancer can be classified into carcinomas and sarcomas according to the fetal germ layer from which tumors arise. Carcinomas arise within tissues derived from the fetal ectoderm or endoderm and include most of the common cancers in adults. Sarcomas are seen more frequently in children and arise from tissues originating from the fetal mesoderm which generate tumors of the bone, muscle, connective tissues, and blood vessels. In developed countries, about 50% of all cancer cases are carcinomas of the lung, colon, prostate, and breast while hematological cancers (leukemias and lymphomas) account for about 8-10% of all cancer cases.1,2

The genetic basis for cancer is well established through studies with tumor viruses, carcinogenesis models, molecular biology, somatic cell genetics, and genetic epidemiology. Cancer is the result of multiple mutations that occur in oncogenes, tumor suppressors and/or DNA repair genes of somatic cells. Although in some cases these mutations can occur in the germ line and are the cause for genetic predisposition, the majority of cancers are sporadic and arise due to somatic mutations in the tumor cells.3-14 Cancer follows a characteristic natural history.1-6 First, normal cells become dysplastic showing subtle morphological abnormalities indicative of the initiation of transformation. Characteristic abnormalities of both form and proliferation then lead to a carcinoma in situ that does not invade the underlying basement membrane of the tissue of origin. These early phases are highly curable and may be detected with screening programs. Localized cancer is a stage I disease when the tumor exhibits invasion and disruption of local tissues to form a primary lesion. Then tumor cells invade local lymphatics and spread to the regional (stage II) or distant regional (stage III) draining lymph nodes as secondary tumors. Finally, tumor cells invade the bloodstream initiating the characteristic patterns of bloodborne metastasis characteristic of stage IV disease. Staging correlates with survival and provides an essential guide both to prognosis and to the design of treatment plans.1 Tumors vary in the extent to which they follow these phases. Melanoma usually has locoregional phase, while breast cancer is systemic from the beginning.1

10 Ways To Fight Off Cancer

10 Ways To Fight Off Cancer

Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.

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