Cancer of the Uterus in Cats


PetMD Editorial

Updated Aug. 24, 2022

Uterine Tumor in Cats


Uterine tumors are rare occurrences, usually affecting middle-aged to older female cats that have not been spayed. These tumors arise from the uterine smooth muscle and epithelial tissues -- the tissues that line the internal organs and cavities. Cats usually develop malignant metastatic (aggressive and spreading) uterine tumors called adenocarcinomas, tumors that are derived from the glands. These types of tumors are called Müllerian tumors, since the uterus is derived from the Müllerian ducts in the embryo.


Symptoms and Types


  • Vaginal discharge
  • Abnormal estrous cycles
  • Frequent urination
  • Frequent drinking
  • Vomiting
  • Abdominal distention, swelling
  • Infertility, inability to breed successfully
  • Uterine prolapse (displacement of the uterus outside the body)




This cancer tends to take place in female cats that have not been spayed.




You will need to give a thorough history of your cat's health and onset of symptoms. Your veterinarian will perform a thorough physical exam on your cat, taking into account the background history of symptoms and possible conditions that might have led to this condition. A complete blood profile will be conducted, including a chemical blood profile, a complete blood count, a urinalysis and an electrolyte panel to rule out other diseases. 


X-rays will be taken of the chest to check for cancer spread. X-rays of the abdomen should also be taken to detect a possible abdominal mass. An ultrasound provides even greater visual sensitivity, and may be used to reveal a uterine mass during an abdominal examination. A computed tomography (CT) and/or magnetic resonance imaging (MRI) can further detail a mass and enable the most sensitive detection of the cancerfs spread in the body.


If there is abdominal fluid buildup, a fluid sample should be tapped and sent to the laboratory for analysis. A cellular examination of a biopsy taken from the tumor is required for a definitive diagnosis.




The ideal treatment is to spay the cat. However, doxorubicin, cisplatin, carboplatin, and epirubicin are the most rational chemotherapeutic choices for treating cancerous uterine tumors and their spread of disease.


Living and Management


If the uterine tumor is malignant, your veterinarian will schedule follow-up appointments every three months to check for cancer spread and adjust the therapy as needed.  Before each chemotherapy treatment, complete bloodwork will be done. If the uterine tumor is benign, surgery (spaying) is generally curative.

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