The "C" Word
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The “C” word, cancer, is one of the hardest words a veterinarian has to voice to an owner. That word carries a heaviness that is hard to bear for the owner and everyone else who is attached to the pet on the other end. In this article I hope to shed some light on preventative care that can help catch cancer early to aid with treatment which improves quality and quantity of life. We will also discuss what breeds are most susceptible, some clinical signs to monitor for, screening test, newer testing abilities that we can offer to those higher risk individuals, and discuss potential treatments and their side effects.
The difference of terminology
There are a lot of different definitions thrown around in the exam room that can be confusing. I would like to try and clarify these for you. The terminology that often gets misunderstood by owners are: mass, neoplasia, and cancer.
The definition of a mass is a body of coherent matter, usually of indefinite shape and often of considerable size and can also be described as a growth. A mass can range from a wart to a huge cancerous swelling. It just describes there is an abnormal growth on an animal.
The definition of neoplasia is new, uncontrolled growth of cells that is not under physiologic control. This can also be described as a tumor. Neoplasia can be benign, not spreading through the rest of the body or cause significant illness, or malignant, will spread through the body and cause significant illness/harm.
Cancer is used to describe a malignant neoplasm. These are the diseases we are focusing on today and how we can detect and treat to improve quantity, but more importantly, quality of life.
Picture Source: https://wearethecure.org/which-dog-breeds-get-cancer-the-most/
There are a number of breeds that seem to be more susceptible to cancer than others. These include the Golden Retriever, Bernese Mountain Dog, Boxer, Rottweiler, English Cocker Spaniel, German Shepherd, Labrador Retriever, Poodle, Sottish Terriers, and giant breed dogs. Each of these breeds have a risk for different types of cancer that we will touch base on in a different blog. Cats seem to all have an equal chance of not getting cancer. We have not noticed one breed having a higher risk than others.
There are a number of clinical signs that owners note before bringing their animal in for an exam. The most common will be a new, slow or fast-growing mass, lethargy, loss of appetite, increased panting, increased vomiting, weight loss and/or coughing. If any of these signs are noted, the best thing to do is schedule an appointment with your veterinarian and start with an exam and diagnostics (see below).
Screening for Cancer
The first step for this is an exam with a veterinarian. A veterinarian is trained to detect more concerning masses and often the location of the mass gives us clues to know if we should be more alarmed. Your veterinarian will discuss diagnostics with you that can help piece together what is going on with your pet.
1. Cytology. A cytology is taking a needle and extracting cells out of a location. These cells are looked at under a microscope to detect potential cancerous/neoplastic changes and will help us determine if surgery is warranted and the approach of said surgery.
Picture source: https://www.ndsr.co.uk/specialist-referral-service/pet-health-information/oncology/canine-mast-cell-tumours
2. Biopsy. A biopsy is taking out all or a portion of tissue and sending it to a specialist for testing under the microscope. This can tell us exactly what type of cancer an animal has and determine the next best steps for your pet. This approach requires sedation or anesthesia.
3. Lab work. Blood and urine do not always rule out cancer, but there can be clues that tell us it is a higher possibility. We are looking for changes in a cell count, liver/kidney values, changes in protein levels and potential concerning cells noted in a urine sample. Many owners believe if lab work is normal, then we have ruled out cancer. This, unfortunately, is not the case. Lab work must be paired with other diagnostics to make sure there is not dangerous cells lurking in the body. Lab work is recommended annually in older patients (~7 years). This allows the veterinarian to note changes PRIOR to clinical signs, which allows early intervention, longer quality of life, and generally less costly than waiting for clinical signs to arise
4. Thoracic (chest) x-rays. Chest x-rays are screening for primary masses in the chest along with signs of cancer spread into the lungs. Doing these annually in senior patients (~ 7 years) is the gold standard of care. This allows the veterinarian to find cancer BEFORE clinical signs and also allows the veterinarian to compare x-rays from years past to note trends that may otherwise be undetected.
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Source: https://www.vetfolio.com/learn/article/canine-prostatic-carcinoma 5. Abdominal ultrasound. This may be recommended pending what clinical signs are being noted and if the lab work shows signs that may indicate something abnormal with the organs. An ultrasound allows a veterinarian to visualize the liver, spleen, kidneys, abdominal lymph nodes, intestines, urinary bladder, prostate and more. There are some veterinarians that can also use the ultrasound to visualize the heart and lungs. An ultrasound is a vital screening method to try and determine the source of changes.
6. Cancer Screening Test. This is a newer diagnostic available to screen for hemangiosarcoma and lymphoma. This is a wonderful new tool available to catch cancer BEFORE a dog shows any clinical signs. This can help tailor treatment and increase quality of life beyond what was previously thought. This is important for breeds at high risk of developing these types of cancer, such as, Golden Retriever, Boxer, Flat Coated Retrievers, Beagles, Burmese Mountain dogs, Rottweilers, West Highland Terriers, Shetland Sheepdogs, and more. For more information, please follow this link: https://vetmed.tamu.edu/gilab/wp-content/uploads/sites/12/2020/12/Nu.Q%E2%84%A2-Vet-Pet-Owner-Leaflet.pdf
Treatment of Cancer
Picture source: https://www.akc.org/expert-advice/health/chemotherapy-for-dogs-with-cancer/
1. Surgery. If there is an obvious mass then surgery with biopsy is usually the treatment of choice. A biopsy is the gold standard diagnostic tool to determine if a mass is cancerous.
Source: https://www.akc.org/expert-advice/health/chemotherapy-for-dogs-with-cancer/ 2. Chemotherapy. Chemotherapy in pets does not yield the same side effects as those in humans. Given the short life-span of animals compared to humans, we aim to improve quality of life for longer, not so much quantity. We use lower doses of the medications so patients more often than not do not show the severe GI side effects or hair loss noted in humans. We can see a lower immune system in pets, so blood screening during treatment is important to make sure we are tailoring the dose as safely as possible for your pet. There are a number of chemotherapy regimens pending what type of cancer your pet has. An oncologist will go over options with you when that time comes.
3. Radiation therapy. Radiation may be the treatment of choice for many types of cancer. This type of treatment does require anesthesia and can lead to sores in the area, change of hair color, and cause infections. However, it is highly effective at eradicating cancer cells and quality of life can be greatly improved in certain cases.
4. Injections. There are injections now for Melanoma and smaller (< 4 inches in diameter) non-metastatic (has not traveled through the body) mast cell tumors. These can help decrease the risk of surgery and studies are promising at the overall prognosis.
5. Supportive care. If the above options are not available to an owner and/or pet, your veterinarian will discuss other options to help keep your pet comfortable for as long as possible. This can include steroids, pain control, vitamin injections, fluids, and other supplement options.
Many animals, unfortunately, develop cancer in their lifetime. I believe this is due to them living longer and more diagnostics available, catching more cancer than in the past. It is important for us to screen your pet to try and find these changes early on so we can tailor a treatment that is less invasive and can increase both quality and quantity of life. I believe there will be a lot of amazing new tools in the future to help us improve our diagnosing and treating of cancer which will make our pets healthier for longer.
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