What is lymphoma?
Lymphoma is a cancer of the lymphatic system. The lymphatic system is, amongst other things, involved in immunity and fighting infections. Lymphoma arises from cells in the lymphatic system called lymphocytes which normally travel around the body, so this form of cancer is usually widespread.
Lymph nodes (sometimes called lymph glands) are part of the lymphatic system and are located all over the body. Lymphoma can affect some or all of the lymph nodes at the same time. It may be possible to feel or see affected lymph nodes that are near the body surface (as shown in the picture below) – they usually feel big and firm. Lymph nodes deeper inside the body are also often involved, as well as internal organs such as the liver, spleen, and bone marrow. This widespread involvement is not like tumour spread in other types of cancer.
Lymph nodes you can feel
- Submandibular: under the jaw
- Prescapular: in front of the shoulder
- Axillary: in the armpit
- Inguinal: in the groin
- Popliteal: behind the knee
What tests will my dog have?
The diagnosis of lymphoma is usually confirmed by taking a sample from a lymph node, either by fine needle aspirate or biopsy. Fine needle aspirate of a superficial lymph node is a quick, simple procedure using a needle (similar to those used for booster injections) to collect cells from the node. It causes minimal discomfort and is normally carried out while a patient is awake or under mild sedation. In some cases we need to take a biopsy, involving the removal of a larger sample of tissue – this may be carried out under a general anaesthetic. These tests allow a very accurate assessment of the tumour by a Specialist looking at the samples under a microscope.
A fine needle aspirate sample of lymphoma cells seen under the microscope
A solid biopsy of an affected lymph node, viewed under the microscope
Frequently, patients will have samples obtained from their enlarged lymph nodes with a fine needle, just as they do for a fine needle aspirate as mentioned already, and these samples are then sent to a Specialist laboratory for a test called ‘Flow Cytometry’. This is a very new test in canine lymphoma. It allows us to characterise the lymphoma cells much more accurately than we could otherwise manage and it can have a significant impact on prognosis and our decision-making relating to treatment.
To allow evaluation of internal lymph nodes and organs, patients usually have X-rays and an ultrasound scan. Mild sedation is usually required for these procedures, as we need our patients to be very still. Blood sampling is also performed to assess a patient’s general health status.
In some cases we will recommend taking samples of bone marrow to investigate whether or not cancer cells are present in the bone marrow. This procedure is usually carried out under a short general anaesthetic.
All the diagnostic information we obtain allows us to give an accurate prognosis and to discuss appropriate treatment options.
Can lymphoma be treated?
The simple answer is yes. It is very uncommon for lymphoma to be cured, but treatment can make your dog feel well again for a period of time, with minimal side effects. This is called disease remission, when the lymphoma is not completely eliminated but is not present at detectable levels.
Without treatment, survival times for dogs with lymphoma are variable, depending on the tumour type and extent of the disease, but for the most common type of lymphoma the average survival time without treatment is 4 to 6 weeks. With current chemotherapy regimes such as so-called “CHOP” protocols, the average survival time for the most common type of lymphoma is approximately 18 months.
Treatment options will be discussed in detail on an individual patient basis. Options include:
Steroid treatment (Prednisolone):
by itself this increases average survival times to 1 to 3 months, but it does not work in all cases. It will also make subsequent treatment with chemotherapy less successful.
Chemotherapy:
using medications to stop or hinder cancer cells in the process of growth and division.
Clinical Trials:
Please do ask about possible clinical trials for dogs with lymphoma. At present no therapeutic trials are available. However, we are participating in a research investigation into the role of the immune system in the control and development of lymphoma in dogs. Patients who are enrolled in this investigation will receive the same care as other lymphoma patients. In addition, they will receive free cytology and flow cytometry investigations which will enable us to select the most appropriate treatment protocol for your pet. The initial work with this project resulted in us publishing a scientific study in a human medical journal describing the importance of a particular population of white blood cells to every individual patient’s response to therapy and life expectancy. This has led to further work and may even inform trials of new non-chemotherapy medicines for human and canine lymphoma.
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In a separate trial, which is likely to be modified and then available for participation again, dogs with lymphoma were randomised to receive a new therapeutic vaccine for lymphoma following completion of a normal ‘CHOP’ protocol. The initial pilot study for this product indicated an exceptional improvement in outcome for patients receiving the vaccine compared to those who received chemotherapy alone.
What does chemotherapy involve?
On each treatment day, before receiving chemotherapy, your pet’s progress is discussed, together with a full physical examination and blood tests. Following this assessment, chemotherapy doses are calculated and the drugs are administered either subcutaneously (under the skin), intravenously (into a vein) via a catheter, or orally. For many patients, once a complete remission has been established, sometimes even before this, we will encourage your local vet to participate in the chemotherapy protocol too. It is important to achieve a balance between seeing the Specialist sufficiently frequently that the right decisions can be made about therapy and seeing your local veterinary practice sufficiently frequently that they are familiar with your pet’s complaint and how it is progressing.
Chemotherapy with a ‘CHOP’ protocol involves your pet receiving chemotherapy treatments approximately weekly for four weeks out of every five for four and a half to six months. At the end of the treatment plan, if your dog is in remission, therapy will be discontinued. Chemotherapy can be restarted when a patient relapses i.e. when lymphoma comes back. Patients are individuals, so the response varies from case to case, and because of this, all patients receiving chemotherapy are carefully monitored and protocols are adjusted to suit the individual.
Chemotherapy with a ‘lomustine-based’ protocol involves a heavier reliance on an oral therapy. The decision to pursue this treatment plan is driven by the characteristics of the cancer rather than a simple preference for a treatment with fewer injections.
What are the potential side effects of chemotherapy and how can they be minimised?
Side effects can be seen because chemotherapy agents damage both cancer and normal rapidly dividing cells. Normal tissues that are typically affected include the cells of the intestine, bone marrow (which makes the red blood cells, white blood cells and cell fragments involved in blood clotting called platelets) and hair follicles. Hair loss is uncommon in dogs having chemotherapy, but it can be seen in certain breeds that have a continuously growing coat, such as Poodles and Old English Sheepdogs (cats rarely develop hair loss, but may lose their whiskers). Hair usually grows back once chemotherapy is discontinued. Damage to the cells of the intestines can result in changes in appetite or stool consistency and occasionally vomiting. Damage to the bone marrow reduces blood cell production, particularly white blood cells that fight bacterial infection (neutrophils).
Steroids are often used in combination with chemotherapy. These medications can make patients feel that they want to eat and drink more (especially during the first week of therapy when doses are usually higher). Patients should not have their access to drinking water restricted, but it is important not to increase their food intake, as excess weight gain can be problematic. The increased thirst is associated with increased urination, so patients may also need to go out to pass urine more often.
Cyclophosphamide, one of the commonly used chemotherapy agents, can cause irritation to the lining of the bladder, producing cystitis-like signs. You may be asked to bring urine samples to an appointment. You should monitor your pet’s urination very carefully, and to promptly report any signs of problems.
Doxorubicin, another chemotherapy agent, can cause damage to the heart muscle over time. The more doses your dog has, the greater the risk. For this reason, heart checks are carried out during the treatment course. The nature of those checks is determined by our level of concern about a possible heart problem. Heart complications are extremely uncommon and your dog is at much greater risk if the lymphoma is not treated. There is a medication that dramatically reduces the risk of heart-related problems. We would always use this if we knew we were going to have to administer a significant number of doxorubicin doses.
We prescribe medications to help to prevent complications, and we will advise you on which signs to monitor. Compared to human patients who receive chemotherapy, pets experience fewer and less severe side effects, and these can usually be managed at home. This is because we use lower drug doses and do not combine as many drugs as in human medicine. Your pet’s quality of life is really important to us, just as it is to you.
What precautions do I need to take at home, with my pet having chemotherapy?
Chemotherapy agents can be excreted in the urine and faeces, and care must be taken when handling your pet’s waste. You will be advised of appropriate precautions, and it is important to note explicitly that pregnant women should avoid contact with the pet’s waste following chemotherapy.
Read more Lymphoma In Dogs: The Complete Guide
What should I look out for?
Signs of gastrointestinal upset: if your pet has vomiting or diarrhoea for more than 24 hours please contact us or your usual vet. Also watch for particularly dark coloured faeces (black).
Signs of bone marrow suppression: Neutrophils (infection-fighting white blood cells) are at their lowest point usually 5 to 7 days after treatment. If your pet is depressed, off its food, panting excessively or is hot to the touch at this time, please contact us.
Signs of bladder problems: you should alert us if your dog is urinating more frequently than he or she has been, is straining or having difficulty passing urine, or if you see blood in the urine.
What will happen in the future?
Unfortunately, chemotherapy for lymphoma is very unlikely to cure your pet, but will allow a good quality of life to be enjoyed for some time. Inevitably, the cancer cells become resistant to the drugs we use, and the cancer will come back. At this stage, it is usually possible to get the cancer back under control, either by restarting the same chemotherapy protocol that we used originally (if the remission was reasonably long-lasting the first time) or by instituting treatment with alternative agents (this is known as a ‘rescue’ treatment). Eventually, the tumour cells will become resistant again and it is likely that your pet will have to be put to sleep when his or her quality of life deteriorates.
Hopefully, this will be after many happy months of good quality life for your pet and you to enjoy together.
If you have any queries or concerns, please do not hesitate to contact us.
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— Update: 13-02-2023 — cohaitungchi.com found an additional article Lymphoma In Dogs: The Complete Guide from the website www.kingsdale.com for the keyword is lymphoma in dogs curable.
Has your dog been diagnosed with lymphoma or are you concerned that your dog may have lymphoma? Lymphoma in dogs is a cancer of the lymph nodes and is one of the most common types of cancer in dogs. There is no known cause for lymphoma in dogs, but it is believed to be caused by a combination of environmental and genetic factors. Treatment options range from surgery to chemotherapy and radiation therapy. While lymphoma can be a serious disease, with early detection and treatment, dogs can live long happy lives. Early detection is key to treating this disease. To learn more about lymphoma in dogs, please continue reading!
What is lymphoma in dogs?
Lymphoma in dogs is a type of neoplastic cancer that develops in the lymph nodes. The lymph nodes are part of the lymphatic immune system, which is responsible for protecting your dog’s body from a variety of infections. Lymphoma can also develop in other organs of the lymphatic system, such as the spleen or bone marrow but the lymph nodes are the most common site in affected dogs. Lymphoma is one of the most common types of cancer in dogs and it usually affects middle-aged to older dogs. There are a variety of breeds susceptible but the Golden Retriever is the most commonly affected breed.
Generally speaking, there are two types of lymphoma in dogs. B cell lymphoma arises from B lymphocytes, which are antibody-producing cells in the humoral immune system. T-cell lymphoma is derived from T lymphocytes (e.g., helper T cells, cytotoxic T cells), which are part of the cell-mediated immune system. Dogs diagnosed with B cell lymphoma generally have a better prognosis than those dogs diagnosed with T cell lymphoma.
What are the causes of lymphoma in dogs?
The underlying cause of lymphoma in dogs is poorly understood. Possible contributing factors include genetics, environmental and immunologic conditions. There is ongoing research into these factors.
Breeds with predispositions suggest that there may be a genetic component to lymphoma. Living near incinerators, radioactive waste, pollution sites, or industrial areas have been linked to lymphoma in dogs. Researchers found an increased risk in households where pesticide lawn care products were applied professionally. Another study showed the use of paint or solvents by owners has been linked to an increased risk of lymphoma in dogs.
Symptoms of lymphoma in dogs
For dogs, lymph nodes are the most commonly affected site. Therefore, the symptoms of lymphoma in dogs include:
- Generalized lymphadenopathy (enlarged lymph nodes) is one of the most common symptoms of lymphoma in dogs and in some dogs this is the only symptom. Lymphoma occurs when the cells of the lymph nodes begin to grow uncontrollably. The most noticeable lymph nodes include the submandibular and prescapular (lymph nodes in the neck region), axillary (armpit region) and popliteal (behind the knee region). The enlarged lymph nodes can be quite pronounced and are typically non-painful.
- Anorexia
- Weight loss
- Lethargy
- Fever
- Increased thirst and urination (polyuria and polydipsia)
How is lymphoma in dogs diagnosed?
Other baseline diagnostic tests that may be performed include:
Complete blood cell count (CBC) – an increase in lymphocytes (a type of white blood cell) is often seen with lymphoma. Anemia can also be present (red blood cell count is low).
Biochemical profile – this blood test evaluates the organs and metabolic system. It may be normal or show abnormalities depending on the type of lymphoma present.
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Urinalysis – Urinalysis is a helpful way to assess kidney function and rule out any hidden urinary tract infections before starting immunosuppressive chemotherapy.
Tests to stage lymphoma in dogs
Testing to see how far cancer has spread (staging) can help us determine the best way to treat your dog’s lymphoma and give a better idea of how well they might respond to treatment. Treatment for lymphoma in dogs usually involves system-wide therapy, so staging tests rarely change our initial approach, especially if the baseline tests are normal. However, in some cases, full staging may not be necessary, especially if the cost and invasiveness of the tests are taken into account.
Abdominal ultrasound – lymphoma can also affect lymph nodes in the abdomen and the spleen is another common site for lymphoma to spread. This test is necessary for tumour staging purposes.
Thoracic x-rays – lymphoma can also involve lymph nodes in the chest cavity so chest x-rays must be performed. This will also help stage lymphoma in dogs.
Bone marrow biopsy – this test can identify lymphoma cancer cells in the bone marrow which typically occurs in late-stage forms of the disease.
What are the stages of lymphoma in dogs?
Staging classifies lymphoma by the extent of the disease.
Stage I – lymphoma cancer cells only affect one lymph node
Stage II – involves multiple lymph nodes in close proximity
Stage III – represents generalized lymph node involvement and enlargement
Stage IV – lymphoma involves the spleen and/or liver
Stage V – involves the CNS (central nervous system) or bone marrow
Paraneoplastic syndromes secondary to lymphoma in dogs
Paraneoplastic syndromes are conditions that occur as a result of lymphoma but are not directly caused by the cancer cells themselves. Paraneoplastic syndromes can be caused by hormones or other substances secreted by the lymphoma cells or by the body’s response to the presence of lymphoma. Anemia (low red blood cell numbers), hypercalcemia (elevated blood calcium levels), hypoglycemia (low blood glucose levels), and thrombocytopenia (low platelet counts) are examples of paraneoplastic syndromes secondary to lymphoma in dogs.
What are the treatment options for lymphoma in dogs?
The most common treatment for lymphoma in dogs is chemotherapy as it is a systemic disease. Chemotherapy drugs work by killing rapidly dividing cells, which includes cancer cells. The goal of chemotherapy is to induce remission, which means that all signs of lymphoma have disappeared.
Chemotherapy protocols
The type of chemotherapy drugs used, the frequency of treatments and the length of treatment will depend on the type of lymphoma present and the stage of the disease. Chemotherapy is typically given as an outpatient procedure, which means your dog can go home the same day.
The two most common chemotherapy protocols used to treat lymphoma in dogs include:
1. CHOP protocols include 4 different types of medications and they are generally considered the most effective protocols for lymphoma in dogs.
2. University Wisconsin- Madison (UW-25) protocol is a 25-week program to treat lymphoma in dogs.
Corticosteroids
Prednisone can directly kill lymphoma cancer cells and may result in short-term remission. However, it does not have a significant impact on survival time compared to no treatment but prednisone can help reduce symptoms and improve the quality of life for patients with lymphoma cancer. Prednisone is typically started at a high dose for the first few weeks, then the dose is slowly tapered.
Tanovea® (rabacfosadine)
Tanovea® is the newest anti-neoplastic drug FDA-approved for the treatment of lymphoma in dogs. Tanovea® was designed to specifically target and attack cancer cells implicated in lymphoma. The drug is given as an intravenous injection every 3 weeks for up to 5 doses. The data from studies show that Tanovea® is highly effective against lymphoma in dogs, with a 60–80% overall response rate.
What is the prognosis for lymphoma in dogs?
The prognosis for lymphoma in dogs depends on the stage of disease, the type of lymphoma present and the response to treatment. With early diagnosis and treatment, the prognosis is good for dogs with lymphoma. The median survival time for dogs with lymphoma treated with chemotherapy is 12-14 months. However, some dogs may only live for a few weeks or months after diagnosis while others may go into remission and live for several years.
In conclusion, lymphoma in dogs is a type of cancer that affects lymph nodes. It is a systemic disease, which means that it can spread throughout the body. The cause of lymphoma in dogs is largely unknown, but it is thought to be related to genetics and exposure to environmental toxins. Chemotherapy is the most common treatment for lymphoma in dogs and the goal of treatment is to induce remission. The prognosis for lymphoma in dogs depends on the stage of disease, the type of lymphoma present and the response to treatment. With early diagnosis and treatment, the prognosis is can be good for dogs with lymphoma. The median survival time for dogs with lymphoma treated with chemotherapy is 12-14 months. However, some dogs may only live for a few weeks or months after diagnosis while others may go into remission and live for several years.
