Chronic cancer is a disease of mammalian cells, and as such, it can affect all animals. Concentrating on human cancer, chronic cancer is typically a terminal illness that is characterized by the uncontrolled growth and proliferation of abnormal cells in the human body. The cells affected could be located in the lungs, in the brain or even the blood; all cells within the human body, and all human organs, can become cancerous. Most cancers develop because of accumulated DNA damage, although more factors than are known may play roles. DNA is a nucleic acid — a biological molecule — that contains genetic information and instructions on how to develop specific components of human cells.
The medical establishment has devised a grouping methodology for the purpose of categorizing the stages of cancer, "stage 0” to “stage IV." A cancer officially diagnosed as "chronic cancer" is much more difficult to treat; stage II to stage IV cancers are typically considered chronic. Stage II cancers are localized to a single area within the body, but are at an advanced stage. Stage III is similar to stage II, but depends on the severity and anatomical location of the cancer. Stage IV cancer is very serious; the designation indicates that the cancer has metastasized — meaning that the cancer has spread to other organs throughout the human body. When cancer has metastasized, the disease is terminal in the majority of cases.
Different types of chronic cancer — such as stage IV chronic leukemia and stage III lung cancer — exhibit a variety of symptoms in the afflicted individual. The symptoms that an individual experiences during the later stages of chronic cancer are entirely dependent on the locality and progression of the disease. For example, a stage III lung cancer sufferer might experience symptoms such as shortness of breath, a persistent dry cough and coughing up blood. A stage IV chronic leukemia patient might experience extreme fatigue and abnormal bleeding. The overall long-term prognosis for chronic cancer is bleak, primarily because the cancers in the aforementioned later stages are notoriously difficult to treat. If traditional treatments, including chemotherapy and radiation, are not working, patients may opt to cease treatment and concentrate solely on controlling the harsh symptoms and pain associated with the disease, often with pain medications such as morphine.