Lymphoma in Dogs and Cats

Lymphoma is a very common form of cancer seen in dogs and cats. It arises from the abnormal proliferation of lymphocytes (a type of white blood cell) within different tissues around the body. Lymphoma most commonly occurs in the lymph nodes, the spleen, and the liver, but the disease can involve almost any tissue in the body, which makes the presentation and course of the disease extremely variable.

Lymphoma is most commonly seen in middle-aged dogs and certain breeds are also predisposed to it, such as boxers and golden retrievers. Most dogs who develop lymphoma get a formed called “multicentric” in which several of the lymph nodes become enlarged. Lymphoma will also commonly affect the intestinal tract, liver, spleen, chest, and the skin.

Signs of lymphoma are extremely variable due to the disease’s ability to affect so many different locations around the body. The most common sign is lymph node enlargement, which may feel like lumps growing below the skin. This is often the only sign present, but some animals with lymphoma can also develop weight loss, lethargy, decreased appetite, vomiting, diarrhea, increased drinking/urination, skin lesions, difficulty breathing, facial swelling, or any combination of these signs.

The diagnosis of lymphoma depends on it’s location but it is most often diagnosed by aspirating cells from the affected organs (lymph nodes, spleen, liver) with a small needle and examining the cells under a microscope. In some cases a biopsy is required to make a diagnosis. Based on aspiration or biopsy results the “grade” of the cancer can also be determined, as well as the cell type present (T-cell versus B-cell lymphoma), both of which help us estimate a prognosis for the disease.

Lymphoma is very serious disease and will almost always claim an animal’s life eventually, however with treatment dogs and cats can life a relatively long period of time, with a high quality of life, doing all the normal things that they love. Without treatment the prognosis is only 1-2 months, with treatment the prognosis depends on the type of lymphoma present and the treatment protocol followed. Treatment for lymphoma is individually tailored to each animal, as well as the time and financial constraints of their owner. Chemotherapy in dogs and cats is usually far better tolerated than in people. We use lower doses, in order to maintain quality of life during treatment, and most animals will have minimal side effects.

In general, the treatment protocols for lymphoma that provide the best survival times and the best chance of putting an animal’s disease into remission are multi-drug protocols. With these protocols animals will generally be given a different chemotherapeutic drug every 1-2 weeks for 6 months or longer. Other treatment options include single drug chemotherapy protocols or treatment with steroids alone. These options are less costly than multi-drug protocols but generally the remission times and survival times are not as long.

We understand how scary it is to have a family pet diagnosed with a cancer such as lymphoma, however by working with your veterinarian and local veterinary oncologist lymphoma can be managed to allow you to spend the most quality time possible with your pet.

Trevor Miller, DVM

Hemangiosarcoma in Dogs

The spleen is an oblong organ – some would say it is tongue-shaped – seated just below the stomach. While one can live perfectly well without a spleen, the spleen does provide some helpful services to the body. Some of these functions include providing stored blood in times of acute hemorrhage, filters out infected cells, and breaks down old red blood cells.

Hemangiosarcomas are a type of malignant cancer most often found in the blood vessels of the spleen in dogs. It is also found in the liver and is actually the most common tumor found in the heart of dogs. These tumors also present themselves on the skin of a dog and may look like small red moles. Hemangiosarcomas also occur in cats, though very rare. This cancer is often found in German Shepherd Dogs and Golden Retrievers. This cancer is equivalent to Angiosarcomas in humans.

Symptoms of Hemangiosarcoma:
     • Usually the patient is suddenly weak.
     • The patient may be obviously cold.
     • The gums will be pale in color.
     • If the bleed stops on its own, the patient will be dramatically better
the next day or even a few hours later.

Unfortunately, this particular cancer is very aggressive. Most commonly when the hemangiosarcoma is attached to the splee, unless the spleen is surgically removed by an experienced surgeon such as Dr. Carl Koehler (ACVS) of Encina Veterinary Hospital, the pet will eventually pass away due to significant bleeding. Along with a splenectomy (removal of the spleen), chemotherapy is also typically suggested for the best possible outcome and longest life expectancy in this situation.

Jared Jaffey, DVM

Why You Should Spay or Neuter Your Pet for Their Health

Why should I spay my pet?
We’ve all heard of breast cancer in women. With approximately one in eight women falling victim to this form of cancer, what many pet owners do not know is that the incidence of breast cancer development in dogs and cats is higher with one in four intact female dogs/cats affected. By spaying your pet before they have their first menstrual cycle there is ZERO chance they can ever develop this disease. The average age a dog has their first heat is 6 months of age, but can be as early as 5 months in small breeds. The average age of a cat’s first heat cycle has their first heat is 6 months of age, but can be as early as 4 months.

If you cannot spay your pet before this time, there are still numerous advantages to having the procedure done as soon as possible. Some of the benefits include prevention of potential life threatening complications with birthing of puppies/kittens, uterine infections, diabetes, bone marrow toxicity, hair loss, pyometra (the uterus becomes very infected, fills with pus and becomes life threatening), behavior problems and of course, pet population

Why should I neuter my pet?
Neutering, or removing your pet’s testicles, is paramount in their behavioral development as well as their health. Much of a male canine or feline’s behavior is driven by a hormone called testosterone, which is primarily made in the testicles. This hormone increases their sense of being leader of the pack and behavior that follows including, urinating in the house, mounting/humping, and inter-animal aggression. Research has shown that the #1 behavior decreased by neutering your cat is running away from home or “wandering”.

As in human males, there are numerous testosterone related problems with the prostate. Luckily in pets you can stop this hormone from being produced by shutting down the factory. This will eliminate your favorite boy from developing prostatic abscesses, enlarged prostate (BPH), and cancers that can all be extremely painful and make it very difficult to even urinate. In addition to these infections, keeping your pet’s testicles intact dramatically increases the chance of developing painful ulcerative lesions around their anus as well as hernias.

In conclusion, there are many beneficial reasons to spay or neuter your pet which may be further discussed with your veterinarian at Encina Veterinary Hospital in Walnut Creek, California.

Jared Jaffey, DVM

Cancer in Pets 101

Encina Veterinary Hospital’s board certified veterinary oncologist, Dr. Stephen Atwater, has taken some time to answer some questions that many pet owners may have regarding cancer in their pets.

Why did you decide to specialize in oncology and how rewarding is it to you?
I had the opportunity to be part of a world renowned oncology program at Colorado State University. It was such an honor to be a part of that program which has helped to develop treatments for cancer in people. Practicing veterinary oncology is extremely rewarding. I get the opportunity to work with very dedicated owners to help extend their pet’s lives providing owners and their pets additional good quality time together.

What are some common options for treatment when a pet is diagnosed with cancer (including holistic/diet)?
The common types of treatments of cancer in animals include surgery, chemotherapy and radiation therapy.
Holistic treatments exist as well, but are largely unproven in their benefit. Diet recommendations include feeding a high fat, good quality protein, low carbohydrate diet. Supplementing diets with omega 3 fatty acids and amino acids such as glutamine and arginine are also recommended. Although in theory this is advised, the true beneficial effects of diet are uncertain.

What are some types of cancers you commonly see and treat?
The most common tumors that I see and treat include lymphoma, mast cell tumors, hemangiosarcomas, bone cancer and soft tissue sarcomas.

How is cancer typically treated at Encina Veterinary Hospital?
Surgery, chemotherapy and radiation are the most common treatments for cancer in pets.

Are the chemotherapy drugs used on pets the same as the ones used on humans?
Most of the drugs used to treat cancer in animals are the same drugs that are used to treat cancer in people.

When a human undergoes chemotherapy, they seem to suffer a lot (nausea, lethargic, etc); do our pets suffer this same way when they undergo treatments?
Animals that receive chemotherapy typically tolerate the treatments well. In veterinary medicine, we appreciate that owner’s primary goal in treating their pets is to maintain a good quality of life. If that was not the case, most owners in their right mind would elect to discontinue treatment. As a result, doses of chemotherapy in dogs and cats are designed such that most animals will tolerate the treatment without significant side effects. If side effects do occur, we are quick to address them with medication to control the signs and potential adjustments with future doses to avoid additional side effects.

Can a pet ever be cured of cancer?
There are many types of cancers in animals. Some forms of cancer in animals can be cured with treatment. This is particularly the case with tumors that develop as localized forms of cancer such as soft tissue sarcomas. Many types of cancers that are localized can be cured with wide surgical excision.

Like humans, pets have remission periods. How long do these periods typically last in pets?
Some animals have cancers that are very resistant to treatment and the animal never goes into remission. Others can be cured of their cancer and are in remission for the rest of their lives. Based on the type of cancer and extent of the disease, remission times can vary greatly. It is based on this information that a prognosis can often be provided to owners on what the expectations for their pet is with respect to the likelihood of a response to treatment and for how long.

Does Encina Veterinary Hospital offer clinical trials of cancer treatments?
We do not do clinical trials very often at Encina Veterinary Hospital, but have done some in the past.

Tell us a brief success/happy story of a patient of yours who stands out in your memory.
Maggie is a Shih Tzu that was diagnosed with lymphoma and was treated with a course of chemotherapy. She relapsed about a year after she completed her first treatment and received another course of the same treatment. She never had recurrence of her cancer after the second round of chemotherapy and survived over 10 years from diagnosis of her lymphoma and had to be put down due to non-cancer related causes.

If you would like to schedule an appointment with Encina Veterinary Hospital/East Bay Veterinary Specialists and Emergency’s Board Certified Veterinary Oncologist, Dr. Stephen Atwater, please give us a call at: (925) 937-5000