Like with humans and other mammals, rabbits can be affected by several types of cancer. Some of these are more common than others and some are preventable. The therapy options available to rabbits will vary on a case-by-case basis and depend upon several factors.
What is cancer?
All cells in the body are constantly dying and being replaced – this is normal. Cancer is a condition where abnormal cells, located in a specific part of the body, grow and reproduce. These cancerous cells can then invade and destroy surrounding healthy tissue and organs, being found almost anywhere on or in the body.
Some types of cancer are localised to one area, some can sometimes begin in one part of the body before spreading to other areas. When this happens, this is known as metastasis and often means the cancer is at an advanced stage.
What types of cancer can rabbits get?
The types of cancer and the frequency that rabbits suffer from these cancers is unknown to some degree. Whilst advances in veterinary care have dramatically improved over the last twenty years, what we know about rabbits still lags behind dogs and cats. A variety of reasons are behind this including a lack of knowledge on rabbits, owners being unable or unwilling to pay for diagnostic tests, diagnostic tests being unavailable for rabbits, medications not licensed or available for use on rabbits, etc.
We do know that uterine adenocarcinoma’s (uterine cancer) is common in unspayed female rabbits. Some studies suggest the incidence is up to 80% by the time the rabbit reaches 5 years of age.
Types of cancer that rabbits may suffer from include:
- Adenoma: originate from glandular tissue.
- Carcinoma: begin in tissues that line or cover internal organs, or in the skin.
- Sarcoma: start in bone, fat, cartilage, blood vessels, muscle, other connective or supportive tissue.
- Leukaemia: originates in blood-forming tissue such as the bone marrow, causing abnormal blood cells to be produced and enter the bloodstream.
- Lymphoma: starts in the immune system.
- Central nervous system cancers: commence in the tissues of the brain and spinal cord.
- Thymoma: these tumours affect the thymus gland, but the primary cause might be somewhere else.
How is cancer diagnosed?
Your vet will perform a variety of diagnostic tests, depending upon which type of cancer they believe your rabbit has. This may involve blood tests, fine needle aspiration or biopsy samples, ultrasound, x-rays, MRI or CT scans. It may take several tests before a diagnosis is found, and sometimes referral to a cancer specialist (Oncologist) may be required.
What are the therapy options?
Treatment may involve removing the cancer in its entirety. In some types of cancer, such as uterine adenocarcinoma, mammary tumours, thymomas, osteosarcoma, testicular tumours, localised skin tumours, etc, this may be possible and curative if the cancer has not spread elsewhere within the body. Blood work and imaging, such as x-rays or MRI scans may be required prior to surgery to ascertain this, otherwise putting the rabbit through extensive and invasive surgery is not always in the rabbit’s best interest.
Cancer of the bone marrow, the lungs or lymph nodes, carries a very poor prognosis and surgical intervention is unlikely to be appropriate. Chemotherapy may be appropriate with or without surgery in some cases to help improve the rabbit’s quality of life.
Is chemotherapy in rabbits the same as in human?
In humans, chemotherapy is associated with a variety of side effects. This, in part, is due to the high doses that are given in order to try and affect a cure. Chemotherapy kills off rapidly dividing cells (which is what cancer cells are). However, it cannot differentiate between cancer cells and other rapidly dividing cells (WBC’s, hair cells, skin cells, etc) so affects them all.
In animals, chemotherapy is given at lower doses, so side effects are less likely and less severe. This also means it may not cure the cancer but may give the rabbit a better quality of life for longer.
Will the treatment cure my rabbit?
This depends on the type and location of the cancer and the treatment used. Spaying may be curative for uterine cancer if it has not spread. Amputation may be curative for an osteosarcoma (bone cancer) as long as it has not spread. However, sometimes even if no spread can be seen upon x-rays/scans, sometimes cellular spread of the cancer, which cannot be detected, may occur. In these cases, the cancer will already have spread and will reoccur within a matter of weeks or months.
Sometimes treatment is aimed at controlling the cancer for as long as possible, whilst the rabbit remains with a good quality of life. When this is not the case, euthanasia is the kindest option.
What if my rabbit doesn’t respond to treatment?
Sadly, treatment is not always successful and if your rabbit does not show improvement or gets worse, then euthanasia is the kindest option, so they do not begin to suffer. While this is upsetting it is the kindest thing to do.
Can cancer be prevented?
Yes and no. Cancers, such as tumours which affect a female rabbit’s uterus (uterine adenocarcinoma), can be prevented if the rabbit is spayed at a young age. Other cancers, such as skin cancer, which is more common in white rabbits (like with white cats), and especially on the ears, can be lessened in likelihood by ensuring the rabbit is not allowed to sit out in the sun and burn their ears.
Other cancers are not as simple to prevent but feeding your rabbit a healthy diet, mostly made up of hay and grass with a small amount of pellets and greens/herbs, allowing them exercise in an enriching environment, keeping them in compatible pairs, monitoring your rabbit’s health and taking them to your vet if you are concerned, are the best ways to try and keep your rabbit healthy.