Cancer is a class of disease characterized by out of control cell growth. There are over 100 different types of cancers and each is classified by the type of cell that is initially affected.
Cancer harms the body when damaged cells divide uncontrollably to form lumps or masses of tissue called tomors (except in the case of leukemia where cancer prohibits normal blood function by abnormal cell division in the blood stream). Tumors can grow and interfere with the digestive, nervous and circulatory systems and they can release hormones that alter body function. Tumors that stay in one spot and demonstrate limited growth are generally considered to be benign.
More dangerous, or malignant, tumors form when two things occur:
1. A cancerous cell manages to move throughout the body using the nlood or ly,ph systems, destroying healthy tissue in a process called invasion.
2. When cell manages to divide and grow, making new blood vessels to feed itself in a process called angiogenesis.
When a tumor successfully spreads to other parts of the body and grows, invading and destroying other healthy tissues, it is said to have metastasized. This process is called metastasis and the results is a serious condition that is very difficult to treat.
Physicians and researchers who specialize in the study, diagnosis, treatment and prevention of cancer are called oncologists.
There are five broad groups that are used to classify cancer.
1. Carcinomas : Carcinomas are characterized by cells that cover internal and external parts of the body such as lung, breast and colon cancer.
2. Sarcomas : Sarcomas are characterized by cells that are located in bone, cartilage, fat, connective tissue, muscle and other supportive tissues.
3. Lymphomas : Lymphomas are cancers that begin in the lymph nodes and tissues of immune system.
4. Leukemias : Leukemias are cancers that begin in the bone marrow and often accumulate in the blood stream.
5. Adenomas : Adenomas are cancers that arise in the thyroid, the pituitary gland, the adrenal gland and other glandular tissues.
Cancer symptoms are quite varied and depend on where the cancer is located, where is has spread and how big the tumor is. Some cancers can be felt or seen through the skin - a lump on the breast or testicle can be an indicator of cancer in those locations. Skin cancer (melanoma) is often noted by a change in a wart or mole on the skin. Some oral cancers present white patches inside the mouth or white spots on the tongue.
When cancer spreads or metastasizes, additional symptoms can presents themselves in the newly affected area. Swollen or enlarged lymph nodes are common and likely to be present early. If cancer spreads to the brain, patients may experience vertigo, headaches or seizures. Spreading to the lungs may cause coughing and shortness of breath. In addition, the liver may become enlarged and cause jaundice and bones can become painful, brittle and break easily. Symptoms of metastasis ultimately depends on the location to which the cancer has spread.
Cancer treatment depends on the type of caner, the stage of the cancer (how much it has spread), age, health status and additional personal characteristics. There is no single treatment for cancer and patients often receive a combination of therapies and palliative care. Treatments usually fall into one of the following categories: Surgery, radiation, chemotherapy, immunotherapy, hormone therapy or gene therapy.