Uterine Cancer in Rabbit – Adenocarcinoma

Meaning

The word cancer represents a group disease characterized by abnormal and uncontrolled growth of cells that crowds out normal body cells in animals. There are many types of cancers in rabbits which including the uterine, bone, ovarian, mammary, lung, among others.

Understanding it

Uterine or womb cancer in rabbits is one of the adenocarcinomas or carcinomas (affects glands that line inside organs) tumors that affect the uterus characterized by malignant (uncontrollable) growth of cells that may damage the uterus and metastasize (travel) to other body organs. [1]

It normally arises from the secretory tissue that lines the uterus cavity (endometrium lining or endometrial glandular epithelium), the myometrium, or the inner layers of the uterus. The other uterine tumor is leiomyoma and leiomyosarcoma.

Uterine cancer can concur with other conditions such as endometriosis, endometrial hyperplasia, endometritis, venous aneurysm (bulging endometrium veins), pregnancy or pyometra. [2]

It is the most common type of cancers that affects rabbits with an estimated 60% of does aged over 3 years being victims with a higher instance in some breeds. [3] Its prevalence stands at about 80% at the age of 5-6 years [4] and it affects the breeding and non-breeding does equally.

In most cases, it metastasizes to the abdomen, as well as other far away organs including bone, skin, liver, eye, brain, lungs, etc.

From its onset, your rabbit is likely to die after one to two years and most pets that have it are often diagnosed with mastitis or mammary cancer.

Risk factors

• Intact does
• Age -higher in does over 3-4 years
• Breed - Affects all breeds with the Havana, Dutch, Tan  [5]and French silver breeds noting a higher prevalence.

Signs and symptoms

• Since it causes hemorrhage, hematuria (blood in urine) is the most common symptom noted. Although the blood comes from the uterus, it is commonly released as it urinates and often occurs at the end of urination. Blood clots may also be observed.
• Vaginal discharges – it may be clear, thick, or stained by blood
• Mastitis– you will notice mammary gland cysts filled with a cloudy to clear fluid
• Mammary gland cancer
• Heightened aggressiveness characterized by biting and lunging on other rabbits, pets or owner
• Abdominal masses in later stages
• Reduced fertility, litter sizes, stillbirths inbreeding does as well as resorption.[6]
• Some late and metastasis symptoms may include anorexia (reduced appetite), breathing difficulties (if it reaches the lungs), lethargy, swollen abdomen, depression, pale gums among others.

Diagnosis

During diagnosis, a pregnancy test is done to exclude the reason for abdominal masses. Also, your vet may look at the various symptoms, consider its age and if your doe is anemic or not.

Additionally, your vet may perform palpitation, recommend X-rays to detect spread (thoracic or abdominal radiographs) or swollen lymph nodes, uterine biopsy, among others that he or she may decide on including an ultrasound.

Treatment of uterine cancer and recovery

So far, there is no effective chemotherapy for uterine cancer in rabbits. However, some of the treatments may include the following:

• Surgical treatment that will come alongside after postoperative care and hospitalization. Also, pain medications such as meloxicam, butorphanol, carprofen, or buprenorphine may be indicated after the operation.
• Blood transfusion in case of excessive uterine bleeding.
• Ovariohysterectomy or hysterectomy (removal of the female reproductive system) or uterus removal.

After treatment, there might be X-rays for up to 2 years done quarterly in case your vet suspected that the cancer was spreading.

You should also monitor eating habits as surgery trauma may make some rabbits not to eat predisposing them to other digestive system complications such as GI stasis. 

Prognosis is good if ovariohysterectomy is done before it spreads to other parts and there are no other related cancers such as mammary one.

After metastasis, expect poor prognosis and without ovariohysterectomy, death in 1-2 years. Your vet may recommend euthanasia in some cases.

Prevention

Ovariohysterectomy or spaying non-breeding does (done between 6 months - 2 years but usually 6-8 months) and in case they are breeding, do it after four years.

Conclusion

Palpation of a pregnant doe will indicate segmental fetuses about a penny size, but uterine cancer may have 1-5cm and painful masses. It is good to differentiate the two if you breed your animals.