Lymphosarcoma

Lymphosarcoma (also known as lymphoma) is a disease of white blood cell that can be thought of like leukaemia in people. It occurs in about 1 in 3000 dogs.

Whilst it is a form of cancer that is serious and fatal if not treated, it can be treated medically with a good chance of success. It is one of the most treatable, and indeed sometimes curable, cancers in dogs and cats.

To date in most case we don’t know why your pet got this disease. The disease can affect a lot of different parts of the body, so that a lot of different problems in your pet may occur. Most of these problems can be dealt with by treating the lymphosarcoma.

Clinical signs

The most common sings in dogs are enlarged lymph nodes. You may notice large lumps appear in various location on your dog, commonly under the jaw and in the neck. You may also notice them in the groin area. These lumps are generally not painful, and your pet usually appears quite well.

Otherwise signs can be very vague but may include:

• Lethargy and exercise intolerance
• Weight loss
• Increased thirst
• Increased urination
• Coughing
• Bloated abdomen
• Vomiting
• Diarrhoea or constipation
• Difficultly swallowing
• Shortness of breath
• Drooling
• Skin bruises
• Hair loss
• Behavioural changes or seizures

Whilst lymphosarcoma is usually generalized other forms do occur, where a particular location is primarily affected. These include

• Gastrointestinal lymphoma in the intestine
• Renal lymphoma in the kidney, particularly in cats
• Hepatic lymphoma of the liver
• Lymphoma of the central nervous system
• Cutaneous lymphosarcoma of the skin

Clinical signs will vary depending on the form of the disease present

Diagnosis

A high degree of suspicion of lymphosarcoma is usually present on clinical examination as the clinical signs are often characteristic. The diagnosis is confirmed by sampling a lymph node. This is often done during the consult by performing a fine needle aspirate. This procedure is less traumatic than a vaccination for your pet, and takes about 30 seconds.

A range of other tests may be performed prior to treatment. These help us give a more accurate prognosis for your pet, though they may not affect the type of treatment recommended. We will discuss these with you prior to treatment. Other tests considered are:

• Full blood screen (important)
• Surgical lymph node biopsy. This is more accurate than a fine needle aspirate.
• Immunohisto typing. This differentiates T and B cell lymphosarcoma, which inturn affects prognosis and sometimes treatment protocols.
• X-rays
• ultrasound

All of these tests may be utlized in cats who less commonly have enlarged lymph nodes. For this reason the diagnosis of lymphosarcoma in cats may be a little more complicated

Treatment

A wide range of options exists for treating lymphosarcoma in pets, both medical and surgical. Some forms of lymphosarcoma can be cured surgically, particularly in cats. Medical treatments are however still the most common form of treatment. As a general rule the more drugs used in a protocol, the greater the chance of success, the higher the risk of side effects, and the greater the cost.

Perth is lucky to be serviced by Australia’s only specialist certified animal oncologist and his associated team in Osborne Park. Due to the high standard of care provided, their access to all the appropriate drugs, and specialist treatment rooms, and the fact that they are at the cutting edge of modern animal cancer therapy, most of our cases, after initial diagnosis will be referred for ongoing treatment at the Perth Veterinary Oncology centre.

The drugs most commonly used include vincristine, cyclophosphamide, doxorubicin, prednisolone, and possible L-asparginase, in varying combinations. However if a drug exists to treat cancer, it has probably been used in an attempt to treat lymphosarcoma and dozens of different protocols exist.

Our patients generally handle the treatments very well. It is worth remembering that even though we describe the treatment as a course, over some months if you feel your pet is not happy you can stop the treatments at any time.

Most side effects if they occur are usually short lived & treatable.

In general expect your pet to feel down on the day of treatment, and possibly the next day. The rest of the time they should be good.

It is worth reminding yourself that what ever happens, your pet will almost certainly live longer and happier on treatment than off it, and there is some chance of your pet being effectively cured of the disease

Statistics

The following cold facts should be used as a rough guide only. Remember that with one animal you could far exceed the averages.

The reason for undertaking such treatments is in part, the belief that you have the 1 in 10 pets that may be effectively cured.

Whatever happens your pet will on average be happier & live longer with this treatment. This regime gives them the best possible chance in life.

Survival without treatment 30-60 days Survival of greater than 120 days is expected with treatment with a markedly improved quality of life.

50% of pets are expected to be alive & happy 12 months later. 25% of pets are expected to be alive & happy 24 months later. A rescue protocol is likely to be necessary in the 24-month period.

The initial assessment (x-ray, blood screen, viral testing and bone marrow sample) allows us to give a better prognosis for your pet but may not change treatment recommendations.

Side effects of medications
All drugs used for treating cancer carry some risk of side effects. This list is necessarily comprehensive because we need you to inform us if you think your pet is having problems.

A lot of these side effects are rare, or transient, and if occur will often occur in hospital, so that we can deal with them.

Vincristine

• Causes severe reactions if leaks outside veins (when its given). Please check the leg it has been given in once a day for 2-3 days for any redness or pain.
• Occasionally causes bowel complaints including pain & constipation
• Bone marrow suppression, or anaemia. This is rare, but we monitor patients for it as we go along.

L-asparginase

• Is generally given as a single dose.
• Allergic reactions (rare) will occur in hospital if occur and are generally treatable. This is the sort of reaction some people get to peanuts, or MSG.
• Possibly causes pancreatitis 3-4 days after being given. Report any signs of inappetence, abdominal pain (cramping), or vomiting.
• Bone marrow suppression, or anaemia. This is rare, but we monitor patients for it as we go along.

Cyclophosphamide.

• Cystitis (inflamed bladder). This can be painful but we can treat it, and it stops as soon as we stop giving cyclophosphamide. If this occurs we change to a different medication.
• You just need to check for blood in your pet’s urine, usually 1-4 days after we give Cyclophosphamide. You would also notice she would urinate more often & appear uncomfortable.

Doxorubicin

• This is the only drug we will use that may cause hair loss (about half of dogs that receive it get some patchiness to their coat. This is less frequent in cats).
• Occasionally cause bloody diarrhoea, 2-4 days after being given.
• Can RARELY cause heart disease. This is rare but irreversible, as it damages the heart muscle. This is rare in dogs & very rare in cats. However if it does occur it is usually fatal.
• Heart disease very occasionally occurs with the first dose but usually only happens after a number of doses. For this reason we limit the number of times we use it.
• It is thought doxorubicin may cause kidney damage in cats so we monitor kidney function as we go along, in cats.
• Causes severe reactions if leaks outside veins (when its given). Please check the leg it has been given in once a day for 2-3 days for any redness or pain.
• Can decrease the number of normal white blood cells. We monitor for this change.

Prednisolone (cortisone)

• Increased thirst & appetite.
• Can cause long-term problems after years of usage, including liver & kidney disease.
• In the short term any side effects are reversible by stopping the medication.
• Prednisolone is the most common cause of side effects in this protocol, though they are generally minor & more common in dogs than cats.