Canine Cancer - Research Article
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| Characteristics / Terms | Hemangiosarcoma | Lymphoma |
| Histiocytomas | Mammary Tumors | Testicular Tumors |
| Mast Cell Tumors | Bone Cancer |
Many texts and references attempt to define Canine Cancer. It is best to start with a simple definition of Cancer, supplied here by the American Cancer Society (ACS). According to the ACS, cancer is a group of diseases characterized by uncontrolled growth and spread of abnormal cells. If the spread is not controlled, cancer can result in death.
Characteristics of Cancer in Dogs
Abnormality: Cells are the structural units of all living things. Each of us has trillions upon trillions of cells, as does a growing tree, a sponge in the ocean, or a dog asleep by the fire. Cells make it possible for us, and for dogs, to carry out all kinds of functions of life: breathing, walking, jumping, digesting food, and so on. However, all of these functions can only be carried out by normal healthy cells. Cancerous cells stop functioning as they should, become useless to the body, or become hostile to the body’s purpose.
Uncontrollability: The most fundamental characteristic of cells is their ability to reproduce by dividing: one cell becomes two, two become four, and so on. In most parts of the body, cells continually divide and form new cells to supply the material for growth or to replace worn-out or injured cells. When a person cuts his or her skin, certain cells leap into action, dividing and dividing, producing news cells until the tissue is healed and the skin is repaired. (Afterwards, they return to their normal rate of division.) In contrast, cancer cells divide in a haphazard manner that does nothing good, and often something bad, for the body. These typically pile up into a nonstructured mass. This mass is known as a tumor.
Invasiveness: Sometimes tumors do not stay harmlessly in one place. Tumors often destroy the part of the body in which they originate and then spread to other parts, where they cause new harm. This is what differentiates malignant growths from benign growths, which remain in the part of the body in which they start. Although benign tumors may grow quite large and press on neighboring structures, they do not spread to other parts of the body. Frequently, they are completely enclosed in a protective capsule of tissue, and they typically do not pose danger to life. Malignant tumors do spread, and are life threatening.
Many diseases: Although cancer is often referred to as a single condition, it is actually comprised of dozens of different diseases. These diseases are characterized by site of origin, method and speed of growth, and character of the abnormal cells. Cancer can arise in many sites and behave differently depending on its point of origin. It is important to understand that cancer originating in one body organ takes its characteristics with it even if it spreads to another part of the body. For example, metastatic lung cancer starts in the lung; even if it spreads to other parts of an organism’s body, it retains the characteristics of its original organ.
In a dog, this abnormal cell phenomenon is called, simply, Canine Cancer. Canine cancer is a common disease which requires prompt and decisive veterinary attention. Dogs with cancer elicit a strong emotional (and, it must be said, economic) toil on the animal’s caretakers. Huge strides are being taken to help veterinarians recognize cancer in dogs and to assist in control and cure. Advances in human cancer diagnosis and treatment often mirror the same protocols veterinarians utilize to diagnose, control, and treat cancer in animals.
Canine Cancer Definitions of Terminology
To best understand cancer, it is helpful to understand a few terms:
Cancer: Any malignant, cellular tumor; cancers are divided into two broad categories of Carcinoma and sarcomas: A carcinoma is a malignant growth made up of epithelial cells (which form a membrane over an organ) tending to infiltrate surrounding tissues and give rise to metastases. A sarcoma is a malignant tumor originating from connective tissue or blood or lymphatic tissues.
Neoplasm: an abnormal new growth of tissue in animals or plants; a tumor.
Benign tumor: One lacking the properties of invasion and metastasis and showing a lesser degree of abnormal cellularity than malignant tumors. These are usually surrounded by a fibrous capsule.
Malignant tumor: Has the properties of invasion and metastasis and displays cells with widely varying characteristics.
Metastasize: to spread throughout the body, of cancer cells.
Growth: any kind of an abnormal increase in size of tissue.
Lump: A growth or fluid-filled cyst or any structure rising above the normal surface of a tissue plane.
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