Medical Terms – Glossary

Palliative: A palliative treatment is one that alleviates symptoms associated with the illness. It improves the quality of life, but does not extend survival time or cure the illness. A familiar example is the use of painkillers, which do not treat the cancer, but do help to reduce discomfort. Another example is palliative radiation therapy,…

Surgery: Surgery is a conventional treatment that removes tumors by cutting them out of the body. While the ideal goal is complete removal, this is not always possible. In these cases, palliative surgery may be recommended: removing some, but not all, of the tumor (also known as debulking). Surgery is generally done under anesthesia, and…

X-rays: X-rays are a form of electromagnetic energy, which can be used to take images of the interior of the body by projecting them onto a film sensitive to their wavelength. Because X-rays are flat, two-dimensional films and the body is three-dimensional, the area being imaged is usually X-rayed from two 90˚ angles. These two…

Gained Life Expectancy: How long do we expect a dog to live if he does not get treatment for his cancer? How long do we expect him to live if he does? The difference between those two numbers is the “gained life expectancy” of that treatment. For example, if we expect that a dog has…

Treatment Plan Analysis: At this point, there is no cure for systemic cancer, so there is no “one right plan” for cancer treatments (the right plan would be the one that cured the cancer). Treatment plan analysis is the process of looking at all of the available treatments for your dog’s cancer and making a…

Quality of Life: How enjoyable is life for your dog? Sometimes cancer treatments may extend longevity, but also increase the number of side effects a dog experiences. If side effects can’t be managed or become too severe, life quality may go down. On the other hand, life quality can also be deliberately increased. Paying attention…

Full Spectrum: This is Dr. Dressler’s phrase to describe an unbiased, results-oriented, strategic approach to cancer care. The goal is to optimize life quality and increase longevity. As a Full Spectrum vet, Dr. Dressler considers and treats all aspects of cancer, including diet, lifestyle, and the psychological well-being of both the patient and the guardian.…

DNA: Deoxyribonucleic acid (DNA) is a chain of molecules that contains the genetic instructions for any living organism. DNA is like a blueprint, a recipe, or a code. It stores information about how the body will develop and function throughout its life. DNA has segments, called genes, which carry this genetic information and help cells…

Fine Needle Aspirate: This is an initial screening procedure which vets use to test a tumor or other site in the body for malignant cells. A skinny needle is inserted into the site, which draws up a small sample of the cells and fluids inside the tumor. The sample can – in many cases –…

Genes: Genes are segments of DNA, which carry codes for specific proteins, functions, and cell processes in the living organism. A gene usually contributes to the control of a small segment of what happens in a cell or in a body. Altogether, genes manage every facet of life on the tissue, organ and body level.…

Double-blind, Placebo-Controlled Study: The preferred way that conventional medicine evaluates treatments. In this type of study, at least two groups of identical (or as near as possible) patients are given treatments. One group receives the actual treatment being studied (the treatment group) and the other does not (the placebo group). Neither the doctor nor the…

Historical Use: This term suggests evaluating treatments by looking at their use over time, rather than using clinical studies. Some drugs, like aspirin (pain relief) and phenobarbital (anti-seizure), were used before the Food and Drug Administration (FDA) started regulating pharmaceuticals. These drugs, which have strong historical evidence of working in the body, are grandfathered into…

Decompensation: When a dog can no longer hide or mask the signs and symptoms of disease and suddenly becomes very obviously sick. Dogs have a talent and instinct for compensation, or hiding their symptoms, which is why they can seem to get sick “overnight” when they finally decompensate.

Prognosis: The overall expected outcome of the cancer case under consideration. The prognosis can include the median survival time, a description of how life functions will be affected, and whether the disease will cause a lingering decline, a sudden crisis, or neither of these. A prognosis is usually classified somewhere along the continuum of “excellent”…

Tumor: A growth, mass, or bump made of benign or malignant cells is a tumor. Tumors can be technically classified as benign (generally not dangerous) or as malignant (dangerous, cancerous). In common use, however, the word is usually used only when the tumor is malignant. If your vet refers to a growth as a tumor,…

Complete Remission: All measurable signs of cancer are gone. However, due to the inherent nature of systemic cancer, measurable signs are likely to return at some point in the future. See remission.

Durable Remission: This diagnosis is achieved when there are no measurable signs of cancer, and there have been no signs for a reasonable length of time. Most oncologists consider a remission “durable” after fourteen to twenty-one days. If a patient cannot stay in remission between treatments, it is typically not an effective treatment.

Ultrasound: Ultrasound is a diagnostic medical imaging technique that can help get a picture of the deeper areas of the body. While this tool’s most familiar use is to check on human baby development during pregnancy, it can also produce an image of the interior of any other soft-tissue organ. In contrast, an X-ray image…

Cure: When cancer is completely absent from the body, and is not expected to return at any time in the future, the patient has achieved a “cure.” Dr. Dressler and Dr. Ettinger, authors of The Dog Cancer Survival Guide, have both seen dogs live long years past their prognosis, and they have also seen cancer…

Side Effect: In any given treatment, a certain effect is desired; for example, a desired effect of surgery might be tumor removal. Any effect other than the desirable effect is called a side effect. Side effects can range from harmless (loss of hair) to harmful (a life-threatening staph infection). Sometimes side effects increase with higher…

Median Survival Time: The time, from either diagnosis or treatment, at which no more than half of the patients with a given cancer are expected to be alive. For example, if a group of dogs all have lymphoma and all start the conventional chemotherapy protocol that Dr. Ettinger recommends, she would expect half of those…

CT Scan: CT stands for computed tomography, which is a medical imaging technique using two-dimensional X-rays taken in a series and digitally computed, or manipulated, so that a three-dimensional image of the inside of the body is formed. Each image shows a “slice”, also called a tomograph, of the body and provides more detail than…

Remission: This term indicates that the cancer has responded, or gone away, to some degree. Vets usually modify this with words like complete or partial, to indicate the degree of remission. In common use, remission is usually synonymous with complete remission. Also see durable remission.

Clean Margins: A biopsy is said to have “clean margins” when the pathologist does not see evidence of tumor cells in the margins of normal tissue examined during the comprehensive margin evaluation.

Partial Remission: This is said to occur when some of the measurable signs of cancer are gone. Most oncologists call a remission “partial” when they see between 50% and 100% response to treatment.

Response: The cancer “responds” to treatment, or gets better. You may hear “her response so far is good” or “he isn’t responding to this treatment.” Sometimes response is also used as a synonym for complete or partial remission.

Chemotherapy: Historically, the word “chemotherapy” referred to the use of any chemical in any medical treatment. Today, it is used to describe the use of pharmaceuticals in a cancer treatment. Chemotherapy kills cancer cells in a variety of different ways, including: increasing damaging free radicals within cancer cells, damaging DNA, blocking cell division, interfering with…

Cytotoxic: Literally, “toxic to cells.” This word is used to describe cancer treatments that are toxic to cancer cells. Unfortunately, these same treatments may also be toxic to other living cells, such as bone marrow cells, hair follicles and the cells of the gastrointestinal tract. Conventional veterinary cancer care seeks a successful balance of cytotoxicity…

Comprehensive Margin Evaluation: An examination performed by a pathologist to see if there are cancer cells along the margins of biopsied tissue. If there are cells on the edge of the tissue sample, there are likely some left in the dog, and another surgery or other treatment may be in order. If cells are present,…

Dirty Margins: A biopsy is said to have “dirty margins” when the pathologist sees tumor cells in the margins of normal tissue examined during the comprehensive margin evaluation. Dirty margins indicate that cancer cells are likely still in the body around the surgical incision or scar.