What Is Cancer?
Cancer is a diverse group of diseases where cells divide without control and often invade other tissues, either nearby tissues (local invasion) or distant tissues (metastasis). Cancer cells can spread to distant tissues via the blood or lymph node system.
Animals get many of the same types of cancers that we see in humans. Most cancers are named for the organ or cell type in which they start. All cancers start in cells, the body’s basic unit of life. A pet’s body is made up of many different types of cells.
Cells grow and divide in a controlled way to replace aging cells and to keep the body healthy. In cancer, this controlled process goes wrong. The genetic material (DNA) of a cell becomes damaged or altered, leading to mutations that speed up cell growth and division. In cancer, cells do not die when they should, and new cells form when the body does not need them. The extra cells may form a mass of tissue called a tumor, of which there are two types:
- Benign tumors aren’t malignant, meaning they do not spread to other tissues. They can often be removed, and, in most cases, they do not come back. Cells in benign tumors do not spread to other parts of the body.
- Malignant tumors are cancerous. Cells in these tumors can invade nearby tissues and spread to other parts of the body. The spread of cancer from one part of the body to another is called metastasis.
Some cancers do not form tumors. For example, leukemia is a cancer of the bone marrow and blood.leukemia is a cancer of the bone marrow and blood.
What Is Chemotherapy?
- Carcinomas—These are cancers that start in skin or tissue that lines or cover the internal organs. Some common examples in pets include cancer of the bladder (transitional cell carcinoma), cancer of the skin (squamous cell carcinoma), cancer of the liver (hepatic carcinoma), and cancer of the thyroid (thyroid carcinoma).
- Sarcoma—These are cancers that start in connective and support tissues. Some common examples in pets include bone cancer (osteosarcoma), blood vessel cancer (hemangiosarcoma), joint cancer (synovial cell sarcoma), and cartilage cancer (chondrosarcoma).
- Round cell tumors—This is a diverse group of cancers including lymphoma, mast cell tumor, histiocytic diseases, leukemias, and plasma cell tumors. The cells often appear round on cytology.
Chemotherapy is the use of drugs to fight cancer cells. Chemotherapy is different from surgery or radiation because it’s a systemic treatment, meaning the drugs treat the whole body.
Chemotherapy is used to treat many cancers. More than 100 chemotherapy drugs are used today in human medicine, and we use these drugs in veterinary oncology too—either alone or in combination with other drugs or treatments. As research continues, more drugs are expected to become available.
Even though we use the same drugs used in human oncology, the effect of chemotherapy on our veterinary patients is very different. We see a much lower rate of side effects such as nausea and tiredness. As our primary goal for your pet is improvement of quality of life, we will change drugs and protocols if serious side effects are noticed.
What Is Radiation Therapy?
Radiation therapy is the use of high-energy particles to kill cancer cells. Radiation therapy treats localized cancer, often in places where surgery is not possible. Radiation therapy, unlike surgery, is delivered in multiple treatments. This decreases side effects to the surrounding tissues.
What Is Cancer Surgery?
Surgery is often the first step in treating cancer. Surgery attempts to remove the tumor from the patient entirely. We obtain biopsy samples from the tissue removed and get information about the tumor from these biopsies. Some tumors are treated with surgery alone; many tumors are treated with surgery and other treatment modalities to achieve the best control over the cancer process.
Oncological surgeries are performed at AIMSS with the highest standard of care and the most up-to-date techniques, with the goal of optimizing the chances of a successful outcome.