uterine adenocarcinoma inrabbits · uterine adenocarcinoma inrabbits uterine cancer believe it or...

PREVENTION = TREATMENTThus far, chemotherapy

has been ineffective for this typeof cancer in rabbits. It is thereforeimperative that both rabbitbreeders and pet owners takethe necessary steps to ensurethat this disease is preventedand routinely screened for. It isnecessary to distinguish between

Without question, uterine adenocarcinoma isthe most common type of cancer found in femalerabbits. This is a condition that is generallyinsidious. Signs that a doe exhibit are usuallysubtle and may slowly worsen over time. Thisdisease is of great importance to BOTH rabbitbreeders and those who own rabbits as pets.

NORMAL ANATOMY

To quickly review, female rabbits generally reachsexual maturity by 4-6 months of age. Larger breedsof rabbits tend to reach this state slightly later in life

around 6-8 months of age. The doe is an induced ovulatorand can develop estrous [receptive to breeding] cycles thatlast around one to two weeks. The female rabbit has twouterine horns and two cervices to accommodate their littersize. As a doe ages, various changes occur in the uterus thatgenerally make them more likely to develop this condition.The most significant is the changing of the uterine wall toinclude more collagen.

Uterine Adenocarcinoma in Rabbits

UTERINE CANCERBelieve it or not, studies 'have been done that show

the incidence of uterine cancer to be higher in certainbreeds. They include the Tan, Havana, and Dutch. The

breeds over the ageincidence in uterine cancer in theseof four can be as high as 50-80%. Despite these breeds thatmay be overrepresented, ageis the number one factor whenconsidering whether or not a doeis afflicted with uterine cancer. Afive-year-old seasoned JerseyWooly brood doe is far morelikely than an eight-month-oldHolland Lop doe to developuterine adenocarcinoma.The disease begins with

only the uterus undergoingneoplastic changes that lead totumor formation. The uterus isan organ with a rich blood supplyand metastatic spread to otherorgans is common. The mostcommon locations include thelungs and liver. The tumor cansometimes grow so large thatthe structure that was formallythe uterus begins to break down

and leaks into the abdomen. This is a serious complicationthat may lead to infection of the abdominal cavity [a septicperitonitis] and ultimately death.

SIGNSClinical signs are the first clues you as a breeder or pet

owner will have to determine if uterine adenocarcinoma is apossibility in your female rabbit. The earlier signs include:• Decreased fertility: A proven doe begins to routinely notconceive after being bred multiple times.

• Small litter size: A doe that consistently gives birth tolarge litters now has one or two kits per breeding. Thesekits may be smaller and less developed than previouslitters.

• Pregnancy complications: Abortions, resorptions,stillbirths, and dystocia may all increase over time.

• Hematuria: Does will have a blood tinged urine stream.Actual [frank] blood may be present at the end of urination.If these signs are not investigated thoroughly, thecondition of uterine cancer worsens and signs becomemore severe. They include:

• Depression: Does will lay in the corner of their cage andact dull, lethargic, and appear sick.

• Anorexia: The doe will eat less food, drink less water,and lose a significant amount of flesh condition quickly.

• Trouble breathing: A doe willlay stretched out with her headextended upwards and mayactually pant. This generallyrepresents the 'presence ofcancer in the lung tissue aswell.

• Swollen abdomen: Calledascites, the doe will have anabdomen .that is only seenduring pregnancy despite hernot being bred reeently. Manytimes a fluid wave can beappreciated with palpation.

A rabbit uterus and cervix is shown in this photograph following anovariohysterectomy {spay surgery]. Note the large amount of fat thatsurrounds the female reproductive organ. This is normal in adult fe-male rabbits. Uterine adenocarcinoma {cancer] has overtaken theentire left {rabbit's right] uterine horn and a portion of the cervix. Theright uterine horn {rabbits left] is completely normal. Note the gray,swollen, and enlarged appearance of the right uterine horn in relationto the healthy, pink tissue of the left horn.

Believe it or not,studies havebeen done that

. show the inci-dence of uter-ine cancer to behigher in certainbreeds.

rabbit breeders and pet owners inthis instance.

Rabbit Breeders: Performroutine abdominal palpations ondoes that are over the age of two.If you recognize any of the abovesigns for uterine cancer, performthe examination immediately.Much like determining if a doeis pregnant, palpation in thecaudal abdomen is a useful andvaluable tool that you have as adiagnostic aid. A pregnant doe

il commonly have segmental, penny-sized fetuses along:: - uterine horns as you gently palpate the abdomen. Does- uterine cancer will have nodules that are between 1-5

ze timeters in diameter and may be painful when palpatedhe doe. If and when the tumor is identified, the doe should

oe spayed immediately by a veterinarian or culled from theherd prior to developing serious complications.

Pet Owners: Prevention is the best medicine for pet owners.you plan to own a female rabbit, you should have her

spayed (an ovariohysterectomy) before she is two years old.

I recommend to my clients with new rabbits that they shouldbe spayed as early as six months of age. The surgery isgenerally less complicated and healing time is minimal. Ifyour rabbit is intact, over the age of two, and experiencing anyof the signs listed above, I recommend scheduling a visit withyour nearest rabbit-savvy veterinarian. He or she will be ableto perform the necessary diagnostics to determine whethera uterine tumor is present and whether or not it has spreadto the lungs or other abdominal organs. Metastatic spreadcarries a grave prognosis. If thetumor is confined only to theuterus, surgery is frequentlycurative

Jay E. Hreiz, MVDChairman. ARBA Rabbit & CavyHealth Committee Dr. Hreiz isa graduate of Penn's VeterinarySchool and currently works as anassociate veterinarian at a smallanimal/exotics practice in theCharlotte, NC area. He is also anARBA judge, #789

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