Domestic rabbits, descendants of the wild European rabbit, began gaining popularity as pets in the late 1800s. By 2024, approximately 1 million American households owned a pet rabbit. Despite this, information on rabbit diseases, including rabbit cancer, is less widely available than information on diseases of other pets, such as cats and dogs.
Key takeaways
- Cancer in rabbits occurs when abnormal cells grow out of control, forming tumors that can be benign or malignant and often require urgent veterinary attention.
- Common types include uterine, breast and lymphatic cancers, with symptoms such as weight loss, lethargy and changes in appetite varying depending on the type of tumor.
- Early detection and prevention, particularly spaying and neutering of female rabbits, can significantly reduce cancer risk and improve outcomes.
What is cancer in rabbits?
Cancer in rabbits occurs when abnormal cells in its body grow and divide uncontrollably, resulting in a tumor. Tumors can be benign (non-cancerous) or malignant (cancerous). Cancer should be considered a medical emergency because its management requires urgent veterinary intervention.
Types of cancer in rabbits
The most common types of cancer in domestic rabbits include:
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Thymoma: This type of tumor originates from the thymus, a structure in the chest cavity that has immune functions.
Other types of cancer, such as testicular cancer and osteosarcoma (bone cancer), are possible but occur much less frequently.
Cancer Symptoms in Rabbits
Symptoms of cancer in rabbits vary depending on the type of cancer.
General symptoms of most rabbit cancers, including lymphoma, include:
Symptoms of uterine adenocarcinoma include:
Symptoms of breast adenocarcinoma include:
Symptoms of thymoma include:
Cause of cancer in rabbits
Cancer rarely has a single cause and usually has a combination of contributing factors.
Cancer risk varies between male and female rabbits due to the types of cancer associated with their reproductive organs. For example, up to 80% of unspayed female rabbits aged 5 years and older will develop uterine cancer, a disease that does not affect males.
The risk of cancer increases with age in rabbits. A study of 93 tissue biopsies taken from pet rabbits found that rabbits at least five years old were 3.85 times more likely to have reproductive tumors than younger rabbits. However, certain types of cancer, such as lymphoma, are also known to occur in young rabbits.
There are over 200 breeds of domestic rabbits. Anecdotal evidence suggests that Dutch breeds may be more predisposed to uterine cancer, while Belgian and English breeds appear more likely to be diagnosed with breast cancer.
Exposure to certain viruses, such as Shope papillomavirus (also called cottontail papillomavirus [CRPV]), is also known to cause malignant tumors in pet rabbits, particularly in Europe and Australia.
How Vets Diagnose Cancer in Rabbits
Your rabbit's veterinarian will start with a physical exam. They may also recommend a series of tests based on their results to rule out certain conditions and make an accurate diagnosis. Tests they may recommend include:
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Imaging tests: X-rays or ultrasound are the most commonly used and can provide valuable information about the location, size and stage of a tumor. More advanced imaging techniques, such as computed tomography (CT) or magnetic resonance imaging (MRI), may be ordered to further evaluate masses in your rabbit's body.
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Biomarker analysis: Substances produced in the body associated with certain types of tumors, called biomarkers, can be analyzed, but this is not routine.
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Biopsy: A definitive diagnosis will require examination of the cancerous cells or tissues under a microscope. Fine needle aspiration (FNA) is the most common and uses aspiration to extract abnormal cells from a tumor mass for examination. Cancerous tissue may also be examined after a tumor is surgically removed.
It is helpful to provide the veterinarian with your rabbit's medical history and a detailed account of the symptoms you have noticed.
Treatment of Cancer in Rabbits
Treatment options for your rabbit will depend on the location, size and type of the tumor, as well as whether it has invaded nearby tissues or spread elsewhere in the body. Your veterinarian will take into account your rabbit's general health and veterinary history.
Surgery is the most common treatment for cancer in rabbits. Complete removal of the tumor is ideal but can be difficult depending on its location and size. In addition to conventional surgical techniques, laser surgery or electrosurgery can be used. The destruction of small superficial tumors by cryotherapy may also be recommended. Post-surgical prognosis is generally good if no additional tumors are present.
Chemotherapy may be prescribed when surgery is not an option or as an adjunct to surgery. There is little information on the effectiveness of chemotherapy in rabbits, although some studies suggest it may be effective in treating lymphoma. Rabbits generally cope well with chemotherapy, but side effects can include stomach upset and poor appetite.
Radiation therapy may be an option for certain types of cancer, such as thymoma, lymphoma, and myeloma (a type of blood cancer originating in the bone marrow). Side effects include hair loss, skin irritation, swelling, and heart failure in rare cases.
Treatment options for cancer in rabbits are limited, and the presence of secondary tumors negatively affects your rabbit's prognosis. In such cases, your veterinarian may suggest palliative care to keep your rabbit comfortable. When your rabbit's quality of life declines, they may recommend euthanasia.
Rabbit Cancer Recovery and Management
Pain management will be key to keeping your rabbit comfortable during and after treatment. Keep a close eye on your rabbit's food and water intake as well as their fecal output. A quiet and comfortable space for your pet will be ideal.
Regardless of treatment, your rabbit will need constant monitoring and veterinary checks for at least several months.
The prognosis for a tumor that cannot be completely removed by surgery is often poor. The life expectancy of these rabbits varies depending on the type of cancer and its characteristics. For example, uterine cancer usually grows slowly and rabbits can live with the disease for months or even years.
There are several things that can help your rabbit feel more comfortable while recovering from treatment or undergoing palliative care:
Cancer prevention in rabbits
Regular, gentle home exams and exotic animal veterinary care can help detect cancer early.
Any symptoms observed should be taken seriously. In many cases, rabbit parents do not notice any symptoms until the cancer is advanced and their pet's quality of life is compromised.
Spaying is essential to prevent uterine cancer. Veterinarians suggest spaying before the age of two, but female rabbits can be spayed at any time.
Malignant tumors resulting from exposure to Shope papillomavirus can be limited by housing pet rabbits indoors.
Chronic inflammation that causes additive stress on the body can promote the growth of cancerous tumors. Feeding your rabbit a high-quality diet, keeping them at a healthy weight, and reducing external stress can help combat inflammation.
Rabbit Cancer FAQs
How long can a rabbit live with cancer?
How long a rabbit with cancer lives depends on the type of cancer, the size and location of the tumor, and whether the cancer has invaded or spread to other parts of the body. Late-stage or aggressive types of cancer can result in an estimated life expectancy of just a few days, while rabbits diagnosed early or with non-aggressive types of cancer can live for months or even years.
