November 30, 2015
Chemotherapy is a long word. The definition doesn’t do justice to the fear derived from a term that means only “chemical treatment”. In reality, “chemotherapy” is a word primarily used for a group of cytotoxic drugs, cell killing medicine used in the treatment of cancers. Cancer is a disease that can occur in any body part, any cell line of the body. Cancer occurs when that particular type of cell goes haywire and starts to divide abnormally, faster and faster, so these abnormal cells become a big mass that invades and overgrows the normal healthy cells. This abnormal mass of cells will eventually infiltrate, overwhelm, and kill the normal cells of the organ or body part they grew from. Finding medicine to combat all the different types of cancer that occur is a challenging job, and the drugs used often come with side effects which are themselves feared.
“Ruby” is a beautiful mahogany coated Irish Setter. She’s a little over 7 years old now, and enjoyed some success in the show ring when she was younger. Her owners bred her after careful consideration and her pups were highly sought after. She was retired from the show ring and breeding and had been happily ensconced as a beloved house pet for many years when one night while brushing her out her owners noted two firm lumps along her jaw line. They didn’t seem painful to Ruby, but on closer examination it looked a little like she had human Mumps. Ruby ate all her dinner that night and was playful on her walk but they decided to get this checked out anyway.
We saw her two days later and found things much as her owners reported. Bright eyed, active, in good weight, Ruby was playful for her exam. Pressure on the swellings below her jaw seemed a bit uncomfortable – she wiggled backwards during that part of the exam. The swellings were located where the back of the mandible, or jaw, meets the neck, a common site for lymph nodes. Lymph nodes filter lymph, a body fluid, cleaning it of bacteria and other toxins before the lymph is returned to the general blood stream. As sentinels for infection trying to enter the body, many kinds of disease might cause them to swell up a bit as they swing into action to defend the body. Ruby was examined along the several key points of external lymph nodes found over her body. We detected two more suspect lymph nodes that seemed enlarged.
As with so much of medicine, there is a standard protocol that is usually initiated, sort of the building blocks of investigation into diagnosing a disease. These steps cannot be lightly skipped, as one should always start out looking for the most common of problems and adding on further tests as deemed necessary to answer and understand the disease completely.
On this day we recommended performing needle aspirates of the masses and a blood panel. A needle aspirate is a straightforward procedure: a needle is attached to a medium sized syringe and gently inserted into the antiseptically cleaned mass in question. The syringe must be large enough to exert enough suction to withdraw a sampling of cells from the mass. Sometimes liquid is present, sometimes nothing appears to come back into the syringe. The needle is carefully separated and then the open syringe reattached to “blow” the cells collected onto clean glass slides. These slides will be stained and examined at the laboratory to identify WHAT the mass is, if there are signs of infection, abnormal cells, perhaps what type of organ it is from. The blood panel does a general check for all body systems and functions, though it will not detect a specific cancer (barring a blood cancer leukemia).
Ruby’s aspirate confirmed that the masses under her jaw were her lymph nodes. In a normal adult dog over 80% of the lymphocyte cells are small, round “Mature” cells. In Ruby’s aspirate more than 50 % were big immature blobs of cells. Ruby’s blood panel was actually normal. Additional tests of x-rays and an abdominal ultrasound were recommended to check for enlargement of any internal lymph nodes. Her chest x-rays were clean, but the abdominal ultrasound revealed another enlarged node.
These tests were completed in less than a week. With this information we were able to stage Ruby’s Lymphoma cancer and she was considered a good candidate for chemotherapy. This started as a once a week treatment as she cycled through four different medications each month. Vincristine, Doxorubicin, cyclophosamide, asparaginase and prednisone may all be used in the treatment of Canine Lymphoma. Side effects from the chemotherapy can include the same kinds of problems many people report, such as nausea, vomiting, diarrhea, hair loss and worse. The reality is that we treat multiple dogs and cats with chemotherapy for a variety of cancers every year and rarely see discomfort from these things. This is a blessing for both pet and owner and allows us to both recommend and administer chemotherapy comfortably.
Within 2 weeks the lymph nodes under Ruby’s jaw had dramatically returned to normal size. Her owners were unable to tell that she was on medication of any kind, except for a healthier appetite spurred by the prednisone, a steroid. Without chemotherapy, Ruby might have lived 90 days. Although chemotherapy has put Ruby in remission, it is not a permanent cure, and she still requires treatment every couple of weeks, but Ruby is an 8 month cancer survivor and going strong!
Christine B. McFadden, DVM