What are they?
Cancer of the uterus (or womb) is very common in rabbits; in fact, it is probably the single most common tumour in rabbits even though it affects only females. It is usually highly aggressive and rapidly spreads to other abdominal organs and into the lungs.
What causes it?
Essentially, being a female rabbit! Evolution has equipped rabbits with the capacity to breed fantastically fast, but in doing so, the female reproductive tract is so "overactive" that the uterine wall undergoes metaplasia (cells changing form) and then neoplasia (formation of tumours). The most common is an aggressively malignant uterine adenocarcinoma.
What rabbits are at risk?
Any unneutered female rabbit. Statistically, about 40% of does will have uterine tumours by the age of 2 years, rising to 80% at 6 years. Overall, we'd expect 60% of ALL unneutered female rabbits over 3 years of age to have tumours in their uterus. It doesn't seem to matter whether they've been bred or not, or what breed they are, the risk appears to be linked to age, not reproductive function.Any unneutered female rabbit. Statistically, about 4% 80% of does will have uterine tumours by the age of 2 years, rising to 80% at 6 years. Overall, we'd expect 60% of ALL unneutered female rabbits over 3 years of age to have tumours in their uterus. It doesn't seem to matter whether they've been bred or not, or what breed they are, the risk appears to be linked to age, not reproductive function.
What are the symptoms?
Once the tumour grows large enough, it will definitely cause symptoms; typically, these include bloody urine, a discharge of blood from the vulva, weight loss and sometimes abdominal swelling (due to the tumour growing). If the tumour spreads to the lungs, coughing, wheezing and difficulty breathing may be apparent, but usually there are no signs immediately.
How is it diagnosed?
An ultrasound scan will often identify an abnormal mass in or on the uterus; the presence of a tumour can then be confirmed by exploratory surgery. Secondary tumours in the lungs can only usually be detected with an X-ray, but they may not be visible until they have grown to a significant size (so a "clear" X-ray doesn't mean there aren't microtumours in the lungs that are too small to see yet).
How can it be treated or managed?
The only treatment is surgical removal of the uterus and ovaries - however, if the tumour has spread before it can be removed, the prognosis is poor.
Can it be prevented?
Yes, very simply - spay all female rabbits not required for breeding as soon as possible after puberty (usually, at about 5-6 months of age). No uterus = no uterine tumours. Other than this, there are no lifestyle modifications or treatments known that will prevent or slow down the growth of the tumours.