The basics of cancer
If the three worst words are, 'You have cancer', then the four worst are 'Your cancer is back'.
Katie Couric, American newscaster and journalist
Cancer is a complex entity
Cancer through the ages
Modern day cancer research and treatment
Prevalence and mortality varies with each cancer
Risk factors have been identified
Will cancer be conquered within our lifetime?
Expand your knowledge
Very little strikes more fear into peoples' hearts than being told they have cancer. Such a diagnosis can turn a person's world upside down and conjure up thoughts of what lies ahead: pain, disfigurement, disability, nausea, hair loss, or even death. Recent years, however, have seen extraordinary advances in basic cancer research and in the development of more effective methods for the detection, diagnosis, and treatment of cancer. Consequently, while the phrase "You have cancer," may be life-altering, it is not necessarily the devastating, life-threatening diagnosis of generations past.
CANCER IS A COMPLEX ENTITY
In the most basic sense, cancer is the abnormal, uncontrolled growth of previously normal cells. The transformation of a cell results from alterations to its DNA that accumulate over time. The change in the genetic information causes a cell to no longer carry out its functions properly. A primary characteristic of cancer cells is their ability to rapidly divide, and the resulting accumulation of cancer cells is termed a tumor . As the tumor grows and if it does not invade the surrounding tissues, it is referred to as being benign ( Figure 1.1a ). If, however, the tumor has spread to nearby or distant tissues then it is classified as malignant ( Figure 1.1b ). Metastasis is the breaking free of cancer cells from the original primary tumor and their migration to either local or distant locations in the body where they will divide and form secondary tumors.
Figure 1.1 Benign vs. malignant cancers. (a) A benign tumor is a mass of cells that remains within the tissue in which it originally developed. (b) The invasion of cancer cells into surrounding tissues is the hallmark of a malignant tumor. Malignant cells may break free from the tumor and travel to other locations in the body through the process of metastasis. Source:
Do benign or malignant cells form metastatic tumors?
There are many types of cancer
Cancer is not a single disease; there are over 100 identified types, all with different causes and symptoms. To distinguish one form from another the cancers are named according to the part of the body in which they originate. Some tumors are identified to reflect the type of tissues they arise from, with the suffix - oma , meaning tumor, added on. For example, myelos- is a Greek term for marrow. Thus, myeloma is a tumor of the bone marrow, whereas hepatoma is liver cancer ( hepato- = liver), and melanoma is a cancer of melanocytes, cells found primarily in the skin that produce the pigment melanin. ( Table 1.1 )
There are four predominant types of cancer
The four major types of cancer are carcinomas, sarcomas, leukemias, and lymphomas. Approximately 90% of human cancers are carcinomas , which arise in the skin or epithelium (outer lining of cells) of the internal organs, glands, and body cavities. Tissues that commonly give rise to carcinomas are breast, colorectal, lung, prostate, and skin. Sarcomas are less common than carcinomas and involve the transformation of cells in connective tissue such as cartilage, bone, mus