Medical Oncology: Feline Low-Grade Lymphoma
What Is Low-Grade Lymphoma?
Lymphoma is a cancer of lymphocytes. Lymphocytes are part of the immune system. Low-grade lymphoma is also called small cell lymphoma or lymphocytic lymphoma. The most common location for low-grade lymphoma in cats is the gastrointestinal tract (stomach/intestines/colon) and internal lymph nodes.
What Are The Clinical Signs?
Cats with low-grade lymphoma show weight loss, vomiting, diarrhea, and decreased appetite. These signs usually develop slowly, over months to even years. These signs overlap with inflammatory bowel disease (IBD). Some cats with IBD can go on to develop low-grade lymphoma.
What Diagnostics Are Performed?
Blood work is done as part of a general health screen and to examine for other health conditions before treatment. Blood work can show evidence of internal bleeding from a tumor or problems absorbing nutrients.
Some cats with low-grade lymphoma have intestines that feel thick. Cats can also develop tumors or large lymph nodes in their abdomen that can be felt. Some cats have normal exams. An abdominal ultrasound is a non-invasive test that can show changes in the appearance of the intestines in those cats.
The next step is to obtain a sample of the intestine, lymph node, and/or tumor(s). Options
for obtaining a sample include biopsy or cytology.
The most accurate way to diagnose lymphoma is with a biopsy procedure. This could mean surgery or endoscopy. With surgery, pieces of the abnormal structures in the abdomen are removed and submitted to a pathologist. The benefit of surgery is the samples are larger, and therefore more likely to be diagnostic.
With endoscopy, a tiny camera on a flexible tube is passed into the intestine through the mouth. A small biopsy tool is passed along with the camera. Samples are pinched off from the inside of the intestine and submitted to a pathologist. Endoscopy is less invasive than surgery. But the samples are small and may not be able to determine between inflammation and cancer. Only a small portion of the gastrointestinal tract can be examined with endoscopy.
A fine needle aspirate with cytology is less invasive than surgery or endoscopy. Results are available faster than a biopsy. While the chance of obtaining a certain diagnosis is lower with cytology than with biopsy, this is a reasonable first step.
Additional testing on cytology or biopsy samples is often done. This is to distinguish inflammatory bowel disease tumors from low-grade lymphoma. There are additional fees for these tests and results may take a week or more. This testing is important because it changes treatment plans and prognosis.
Low-grade gastrointestinal lymphoma does not typically spread beyond the abdomen. Staging tests are recommended to be sure this is true. This entails abdominal and thoracic imaging (x-rays, ultrasound, or CT scans).
Treatment Options:
Low-grade lymphoma is treated with two oral medications: prednisolone (steroid) and chlorambucil (chemotherapy), which are given at home. Treatment is chronic (years to lifelong). In the beginning, cats are monitored monthly with exams and lab work. If a positive response is seen (cat gains weight, stops having vomiting/diarrhea), rechecks are spaced out every 2-3 months. Repeat abdominal ultrasounds are recommended to monitor response to treatment. Some cats are also given vitamin B12 supplementation (injections or oral tablets).
Prognosis
The median prognosis for low-grade lymphoma is 2-3 years with treatment.
What Are The Side Effects?
Prednisolone and chlorambucil are well-tolerated. The biggest challenge for owners is
being able to give their cat medications. We will assist you in ways to be successful in
doing so.
How Do I Prepare?
We understand this is a difficult time and we are here to support you and your pet by
providing the options and care necessary. Selecting a therapy is not binding and can be
adjusted to you and your pet’s needs. You will be updated on your pet’s response to
treatment and plan.
Getting Started
Once you have determined the best therapeutic option for your pet, you will work with
our oncology team to develop an appointment plan.
Scheduling: Patients undergoing chemotherapy treatments must have a scheduled
appointment before arrival:
- Schedule your appointments at reception upon check out
- Drop-offs are requested between 7:30-8:30 am
- No discharges are done between 2:30 pm- 3:30 pm as our oncology team is in rounds