Cancer

Cancer is a fatal disease caused mainly by genetic or environmental factors that mutate genes encoding critical cell-regulatory proteins. The resultant aberrant cell behaviour leads to expansive masses of abnormal cells that destroy surrounding normal tissue and can spread to vital organs resulting in disseminated disease, commonly a harbinger of imminent patient death (Malcolm, 2001).

Cancer is the second leading cause of death in the United States. About one-half of all men and one-third of all women in the US will develop cancer during their lifetimes. Today, millions of people are living with cancer or have had cancer (America Cancer Society, 2012).

Over the next 25 years there will be a dramatic increase in the number of people developing cancer. Globally 10 million new cancer patients are diagnosed each year and this will be 20 million by the year 2020. Cancer is now the public most feared disease. Billions of dollars are spent annually on cancer research by the drug industry, cancer charities and governments, but a cure for cancer appear elusive, and yet we are in the midst of a revolution in our ability to image part of the body, painlessly and fine details (Sikora et al., 1999).

Cancer is a group of diseases characterized by unregulated division and spread of cells. The cancerous cells may occur in liquids, as in leukemia. Most, however, occur in solid tumors that originally appear in various tissues in various parts of the body. By their original locations they are classified into various types of cancer, such as lung, colon, breast, prostate cancer, etc. Localized tumors can be removed by surgery or irradiation with high survival rates. As cancer progresses, however, it metastasizes – invading the surrounding tissues, entering the blood stream, spreading and establishing colonies in distant parts of the body. Only a third of patients with metastasized cancer survive more than five years. Invasive distensions spreading crab-like from a tumor in the breast were described by Hippocrates. From the crab, karkinos in Greek and cancer in Latin, came the name of the disease and the name of its inducing agents, carcinogens (Dervan, 1999).

The causes of serious ill-health in the world are changing. Infection as a major cause is giving way to non-communicable diseases such as cardiovascular disease and cancer. In 1996 there were 10 million new cancer cases worldwide and six million deaths attributed to cancer. In 2020 there are predicted to be 20 million new cases and 12 million deaths. Part of the reason for this is that life expectancy is steadily rising and most cancers are more common in an ageing population. More significantly, a globalization of unhealthy lifestyles, particularly cigarette smoking and the adoption of many features of the modern Western diet (high fat, low fibre content) will increase cancer incidence (Malcolm, 2001).