Part I of this blog covered my dog’s cancer diagnosis, symptoms of mast cell tumors in dogs, and coping tips. This installment will cover treatment options for mast cell tumors, factors to include in your decision-making process, and where we’re at with Sally’s cancer.
Diagnostics and Medications
You may be wondering exactly how it was discovered that Sally had cancer. Dr. Meyer, Sally’s dermatologist, diagnosed her mast cell tumor with a fine needle aspirate sample; fine needle aspiration (FNA) employs a needle and syringe to extract a sample of cells from a suspicious lump. The cells are then examined under a microscope to determine if they are cancerous or benign. FNA is the most common way to diagnose mast cell tumors, although biopsy may also be used.
Dr. Meyer prescribed two medications for Sally – an antihistamine and a stomach protectant (i.e. Pepcid). The reason Sally required these medications is that mast cells are composed of allergy cells. As such, they can release histamine when poked, squeezed, or prodded. Histamine can cause a severe allergic reaction, including life-threatening anaphylactic shock. Avoid touching your dog’s mast cell tumor, and don’t allow them to scratch or chew at it. Mast cells can also cause gastrointestinal ulceration, hence the Pepcid.
Cancer Specialists
If this is your pet’s first mast cell tumor, you may not need to visit an oncologist. If your pet has had several, or you’re dealing with a more aggressive cancer type, I would encourage you to do so. Oncologists have the most reliable information about cancer types and treatments. Even if it’s unlikely that you’ll pursue treatment, they can often help you create a plan to keep your pet comfortable at home and help know when it may be time to euthanize.
Sally saw one of Animal Emergency & Referral Center of Minnesota’s oncologists, Dr. Keepman, the next week. He performed an ultrasound to ensure that there wasn’t additional cancer elsewhere in Sally’s body. Fortunately, no metastasis was seen.
Treatment Options for Mast Cell Tumors:
- Surgical Removal
- Surgical removal is the most effective treatment option for mast cell tumors that have not yet spread. It is important for the surgeon to remove both the mass and an area of healthy tissue around it to get complete surgical margins. For Sally, the oncologist warned that it could be difficult to remove her mass with complete surgical margins, since there was not sufficient tissue near her front left leg.
- Low grade tumors are usually cured with surgery if complete surgical margins are obtained. Even with incomplete margins, only 20-30% of low-grade tumors will recur. The metastatic rate for low grade tumors is also low (10-15%). However, follow-up therapy including radiation therapy and/or chemotherapy is often recommended for high-grade tumors.
- Radiation Therapy
- For pets who cannot undergo surgery, who have incomplete surgical margins, who have tumors that have metastasized or are in an area with a poor prognosis for surgical removal such as the mouth or jaw, radiation therapy may be considered. Radiation therapy involves daily treatments for two to three weeks. Beams of radiation are directed and centered on the tumor or the surgical incision. Pets undergo anesthesia for treatment so that they remain immobile, and the treatment is not painful.
- Depending on where you live, it may be challenging to find a specialty center that provides radiation therapy.
- Chemotherapy and Electrochemotherapy
- Again, chemotherapy and electrochemotherapy are often used if surgery is not possible, surgical margins are incomplete, or tumors have spread. Chemotherapy can prolong life by shrinking tumors, but by itself, it may not be effective at eliminating them.
- Electrochemotherapy involves injecting chemotherapy systemically into a vein, then administering electropulses around the surgical incision to increase the likelihood that remaining cancer cells will absorb the chemotherapy. This treatment is painful, so pets undergo general anesthesia. Standard protocol involves two treatments, two to four weeks apart.
Factors to Include in Your Decision-Making
Whether to pursue cancer treatment for your pet and which treatment to choose is a personal decision. Consider the following:
- Prognosis: How will treatment impact your pet’s longevity and quality of life? Conversely, how will foregoing treatment affect the same? Age and overall health should also be considered.
- Finances: Surgery, radiation, and chemotherapy can be very costly. It is important to know what your total bill may be if you opt to move forward, how you intend to cover it, and how that expense will impact the rest of your family budget.
- Emotional impact on you. Review these different scenarios:
- You pursue treatment, and your pet experiences a normal life expectancy.
- You pursue treatment, and your pet’s cancer takes their life in a short period of time.
- You decline treatment, and your pet’s cancer takes their life in a short period of time.
- You decline treatment, and your pet experiences a normal life expectancy.
I’m guessing that the first and the last scenarios leave you feeling happy, while the second and third scenarios may fill you with fear and sadness. There are no guarantees that your pet will live a normal life expectancy, even with treatment.
Personally, I can accept Sally passing away earlier if I know I’ve done what I can. However, you may regret the expense of cancer treatment if your pet dies in a short period of time. Everyone is different.
Where We’re at with Sally’s Cancer
Sally’s tumor was surgically removed on May 14th. She was prescribed pain medications, and she wore an Elizabethan collar for 14 days to ensure she wouldn’t remove her stitches. Her recovery was smooth and uneventful.
Sally’s pathology report revealed that her tumor was low-grade (good news) but that there were incomplete surgical margins (bad news). Because surgery with complete margins can be curative, I asked the surgeon to review Sally’s surgical scar to see if additional tissue could be removed. The surgeon was not confident that she could get larger margins due to where Sally’s tumor had been located.
I have decided to proceed with electrochemotherapy for Sally to ensure her best chance at a long, healthy life. At the time of this writing, treatments have not yet begun, so Sally’s cancer journey is not over yet!
In Part III of this blog, I will cover monitoring your pet’s health, appreciating the time you have together, grief support resources, and I’ll provide an update on Sally.
Learn more about Animal Emergency & Referral Center of Minnesota’s Oncology Service here.
More Reading:
- Common Types of Cancer in Pets | Part I: Determining a Diagnosis
- Debunking Pet Cancer Myths
- Early Detection of Cancer in Dogs and Cats: 5 Things Pet Owners Can Do
- Chemotherapy and Quality of Life in Dogs and Cats
