Diagnosis & Treatment Options For Pet Cancer

There are many feelings that arise when pet owners are faced with the possibility of a cancer diagnosis in their pet. It is common to feel defeated and hopeless. However, is it important to obtain the correct diagnosis and learn about the treatments available, before resigning themselves to the possibility that nothing can be done to save their pet, commonly considered a family member. Seeking referral to a veterinary Oncologist is a good first step to explore treatment options.  Some of the first comments pet owners make is that they don’t want their pet to suffer, and they want the best quality time and not necessarily quantity of time. During the initial consultation these concerns are addressed, and people feel that there is HOPE for their pet. Overall, a common message is that we can help their pet survive cancer and this does not have to be goodbye. Here are a few tips on diagnosis and treatment options for pet cancer, we hope this article brings a little peace in your life.

Naming the disease and the challenge

To provide the options available for treatment, it is important to diagnose the disease and to understand the extent of the pet’s disease, or stage.  Initial testing such as fine needle aspirate, bloodwork, chest radiographs, and abdominal ultrasound serve as a first step to staging.  Based on these results, additional molecular testing, a biopsy, or advanced imaging such as CT may be recommended.  Many pet owners may not be able to afford all of the tests and we understand this.  So, we lay out the ideal plan and work with each client and pet to obtain the most needed information first. Once we fully understand the disease and its extent, then we can understand the challenge ahead and provide a range of treatment options for the individual patient.

Faced with a Cancer Diagnosis, now what?

Treatment for a pet’s diagnosis can be complicated and variable.  Generally, there is not only one option for any dog or cat, even if they have the same disease.  Why?  Treatment options are provided to every pet owner and explained relative to their pet’s diagnosis.  The standard of care treatment is always offered but other options also exist and can be tailored to the wishes of the pet owner based on scheduling, cost, and other illness the pet may have, for example.  Your pet’s cancer team may be composed of your primary care veterinarian, a medical oncologist, surgeon, and radiation oncologist. Often your first visit is to the medical oncologist and they help manage the overall cancer long term treatment plan.  Surgery or radiation may be a part of the treatment but are generally for a shorter period.  The medical oncologist offers chemotherapy and monitoring of the disease over weeks, months or even years!

What does treatment look like? 

Treatment for dogs and cats can consist of surgery, radiation, and chemotherapy.  Surgery and radiation therapy are focal treatments and aim to address a defined mass, for example.  Chemotherapy is a medical therapy and consists of oral, intravenous, subcutaneous or intracavitary treatments.  These are “whole body” treatments.  For instance, some cancers are best managed medically with chemotherapy only, such as lymphoma.  Other cancer requires surgery for removal, and radiation therapy if the removal is incomplete. The best chance for a long-term survival is to plan the surgery.  If tumors are removed without planning, then it is possible that the removal will be incomplete and additional surgery, or radiation will be needed.  If complete removal of the tumor is not possible, then post operative radiation should be planned. Alternatively, if surgery is not possible to remove the cancer, sometimes due to the size of the tumor and location, then radiation can help stabilize the mass or shrink it, helping the pet feel comfortable for longer.  Surgery and radiation are often used with chemotherapy.  A common concern is that chemotherapy will make the patient sick and that the quality of life will suffer.  In fact, most of our patients on chemotherapy enjoy a good quality of life 80% of the time and less than 5% are hospitalized for chemotherapy related illness.  Knowing as much as we can up front allows the Oncologist to provide all the options and to set out a best plan for the patient.  This also sets the pet owners expectations: Are we planning so that the pet can have a chance and a good long-term survival?  Or are we managing the disease for a shorter period? Importantly, the primary goal of the  pet’s cancer team is to maintain the overall quality of life of the dog or cat during any of these treatments. 

Alternative/ Integrative therapies compliment traditional therapy

Pet parents are often concerned with how their pet will feel undergoing traditional treatment options.  Chemotherapy treatment can differ greatly for each pet and there can be side effects, but the goal of our treatment is to make life better, longer.  Chemotherapy is generally well tolerated but side effects can include decreased appetite, nausea, vomiting, or diarrhea.  These are the most seen side effects for patients receiving chemotherapy and they are often mild and self-limiting. 

Acupuncture and herbal medicine are widely recognized tools in both human and veterinary oncology and the list of uses for this therapy is constantly growing!  This therapy has been shown to help relieve pain, improve mood, and alleviate stress and tension and minimize chemotherapy related illness.  Acupuncture can be used to improve appetite and minimize vomiting and diarrhea.  Acupuncture used in combination with chemotherapy can help to achieve our goal of making life better longer.  Our patients enjoy a good quality of life 80% of the time while receiving chemotherapy and this allows pets to be at home with their families enjoying their favorite things!

Acupuncture is well tolerated and there are many different acupuncture points that can be used in all different parts of the body.  In addition to alleviating the possible side effects of chemotherapy, acupuncture can also improve their quality of life by helping to decrease pain, help them rest, and even help with anxiety.  Additionally, through the stimulation of acupuncture points, the body is stimulated to release serotonin and endorphins which help to make them feel better and happier.  This therapy allows us to improve the quality of life in so many ways and give them the best care possible.

How to improve the chances of becoming a survivor: Early

detection is key.

Approximately 40% of pets over 9 years old will be diagnosed with cancer but we can improve outcomes in our pets with early detection.   Some common signs may be vague such as loss of appetite, vomiting, weight loss, diarrhea, antisocial behavior, lethargy, increased thirst and urination, or urinary incontinence.  More specific signs may include the appearance or changes in swellings or masses, non-healing skin lesions, limping or lameness, nose bleeds, or other bleeding, or difficulty eating. Early detection is best accomplished by routine veterinary evaluations and regular assessments by owners at home.  This is important for both dogs and cats.   Dogs commonly form ‘lumps and bumps” that are benign, non-cancerous masses but these must be tested to differentiate between non-cancerous, and cancerous (benign or malignant) lesions.  The most common lumps found on dogs are “fatty tumors” known as lipomas.  These do not have malignant potential but can grow to interfere with the dog’s ability to move or rest comfortably. Others include benign skin cysts and dermal melanoma.  Common malignant skin nodules or masses include mast cell tumors and soft tissue sarcomas.  These have the potential to grow quickly and become locally invasive, making removal difficult.  They can also metastasize.  A definitive diagnosis of these is best obtained using a biopsy which is removal of a piece of the tissue or the entire lesion.  The extent of the removal (a piece of vs. the entire tumor) is based on the ease of removal, size, and location of the lesion.  Additional testing to determine if there is any evidence of metastasis is called staging and may include thoracic radiographs, abdominal ultrasound, fine needle aspiration of local lymph nodes and other lumps (patients can have more than one!) and blood and urine testing.  Importantly, lymphoma often also can appear as “lumps”, but may be enlarged lymph nodes under the jaw and not a mass in the skin as with the others. 

Cats on the other hand, do not commonly form benign, non-cancerous lumps and bumps, and for this reason, all new lesions should be sampled as soon as they are noticed.  One lump that may be non-cancerous is a post vaccine reaction. This may be a swelling that forms days to weeks post vaccination.  Sometimes it may be difficult to differentiate this from an injection site sarcoma which is a malignant and very difficult cancer to treat if not detected early when it is small.  Cats also can form mast cell tumors which tend to be less aggressive than those in dogs but are still considered malignant.  Lymph node swelling due to lymphoma can also occur as in dogs.  Female cats that are spayed later in life also have an increased risk of mammary cancer so lumps on the abdomen should be assessed for mammary cancer. 

Watch it means “watch it grow”.  It is always important to monitor and test all lumps and record on a body map.  Ask your veterinarian to test all growths and for a body map diagram to keep track of all your pets lumps and bumps. We hope these few tips on diagnosis and treatment options for pet cancer, brings a little peace in your life.

By: Melissa Parsons-Doherty, DVM, DACVIM ( Oncology),

Pearland Animal Cancer & Referral Center, pearlandvetreferral.com