Kidney (Renal) Cancer in Cats

Kidney cancer in cats is a complex and serious condition. Kidney cancer, or renal neoplasia, is relatively uncommon in cats compared to other cancers. However, when it occurs, it can be aggressive and challenging to treat. That’s because the kidneys are vital organs that produce hormones, filter waste from the bloodstream, maintain electrolyte balance, stimulate bone marrow to produce red blood cells, and regulate blood pressure. When cancer strikes, these functions can be severely compromised. In this article, we will delve into the intricacies of feline kidney cancer, exploring its types, symptoms, diagnosis, treatment options, and prognosis.

Types of Feline Kidney Cancer

Several types of kidney cancer can affect cats, the most common being lymphoma. Renal lymphoma, often referred to as renal LSA, stands out as the most frequent kidney cancer found in cats. In general, lymphoma is the most common cancer in cats. Surprisingly, up to 45% of cats with LSA affecting multiple body parts also show signs of it in their kidneys. Renal lymphoma is most commonly seen in middle-aged male cats though it can be seen in both sexes. Another important factor to note is the occasional association between renal lymphoma and retroviruses like FeLV (Feline Leukemia Virus) and FIV (Feline Immunodeficiency Virus). Understanding these aspects of renal lymphoma can help cat owners and veterinarians detect and manage this condition more effectively. This form of kidney cancer typically affects BOTH kidneys.

The next most common kidney cancer in cats is renal carcinoma (or renal adenocarcinoma). This cancer arises from the kidney’s tubular epithelial cells and usually affects only ONE of the two kidneys. Thirdly, nephroblastoma, which is believed to be congenital and primarily seen in younger cats, often only affects one kidney as well.

Mesenchymal tumors, though they only comprise about 5% of cases in cats, are concerning because they can be aggressive and spread quickly. These include serious types of cancers like hemangiosarcoma (HSA), fibrosarcoma (FSA), chondrosarcoma (CSA), and leiomyosarcoma.

Benign Kidney Tumors

There are also benign, or non-cancerous, tumors that can occur in cats’ kidneys. These are usually found incidentally as they often don’t cause any symptoms. They include various types like leiomyomas (a type of tumor in smooth muscle tissue), fibromas (tumors in fibrous tissue), and others like adenomas, papillomas, and lipomas. At times, large cysts in the kidney may also present as if it is cancer however cysts are benign as well.

Because the kidneys have a rich blood supply, they are unfortunately a common place for cancer to spread to other parts of the body. This underscores the need for careful monitoring of your cat’s kidneys and timely medical intervention.

Signs and Symptoms of Kidney Cancer in Cats

Feline kidney cancer can be insidious, often showing no early signs which can make treatment more challenging. As the disease progresses, your cat’s symptoms might include:

• Blood in the urine
• Nausea
• Vomiting
• Diarrhea
• Decreased appetite
• Weight loss
• Lethargy
• Abdominal mass or swelling
• Increased thirst and urination
• Abnormal bloodwork such as anemia and elevated kidney enzymes
• Abdominal pain

As you may have noticed, many of these symptoms are not exclusive to feline kidney cancer and could indicate a whole host of other illnesses or health issues. Therefore, it’s important to see your veterinarian for a specific diagnosis.

Diagnosis and Staging Renal Cancer in Cats

Diagnosing kidney cancer in cats is a multi-step process and your veterinarian will likely perform a physical examination of your cat as well as run a slew of tests including:

• Physical Examination: Your veterinarian will feel for abnormalities in the abdomen, and other signs of illness to assess your cat’s overall health.
• Blood Tests and Urinalysis: To assess liver and kidney function, protein levels, and blood cell counts.
• Three-view Chest X-rays and Abdominal Ultrasound: This will help your veterinarian see your cat’s other organs and any signs of metastasis (spread).
• Biopsy or Fine Needle Aspirate (FNA): To confirm the cancer diagnosis, a biopsy or aspirate cytology is performed which involves taking a tissue sample for analysis.
• CT scan: To assess the extent of the cancer and whether or not the affected kidney is surgically resectable.

Once diagnosed, renal cancer is staged based on its size, spread, and impact on bodily functions. Staging helps in determining the treatment plan and prognosis.

Treatment Options

Treatment for feline renal cancer varies based on the type of cancer, its stage, and the cat’s overall health. The following are the most common treatment options for cats with kidney cancer:

• Surgery: If the tumor is localized to one kidney and the other kidney is functioning well, surgical removal of the affected kidney might be an option.
• Chemotherapy: Often used for lymphoma or in other cancers that have metastasized (spread) to or from the kidney(s), chemotherapy can help in managing the disease.
• Radiation Therapy: Though uncommon, radiation may be used to treat tumors that haven’t spread or in combination with other treatments like surgery to ensure all of the cancer cells have been removed and/or destroyed.
• Supportive Care: Regardless of the treatment path, supportive care to manage symptoms and maintain quality of life is crucial. This includes proper nutrition, hydration, and pain management. Cats with kidney cancer may need to be on a special kidney diet for the rest of their lives.
• Palliative Care: Since kidney cancer can be aggressive, sometimes treatment is not recommended and instead, compassionate palliative care is recommended to keep the cat comfortable for as long as possible.

Prognosis for Cats with Kidney Cancer

The prognosis for feline kidney cancer varies widely. Factors affecting the prognosis include the type of cancer, stage at diagnosis, and the cat’s overall health. Renal lymphoma in cats positive for FeLV or FIV generally has a poorer prognosis than in cats with lymphoma who do not have FeLV or FIV. Removing one kidney for a carcinoma can give a good quality of life for quite a while. And some cats with renal LSA also respond to chemotherapy for quite a while. Early detection and advanced treatment can improve outcomes, but some forms of kidney cancer are more aggressive and may not respond well to treatment. The aggressive nature of kidney cancer underscores the importance of seeing your veterinarian regularly for annual physicals and bloodwork. The earlier kidney cancer is detected, the better.

Living with Kidney Cancer

For cats diagnosed with kidney cancer, quality of life is a primary concern. Regular veterinary check-ups, a comfortable and stress-free environment, and proper management of symptoms can make a significant difference in the quality of your cat’s life and the time you have together. Palliative care may be an option when the focus shifts from treating cancer to ensuring the cat’s comfort, happiness, and overall quality of life in your remaining time together.

As a pet parent, understanding the signs, advocating for early diagnosis, and exploring all treatment options is vital to helping your furry family member. Work with your veterinarian who will guide and support you through this difficult journey, providing your beloved cat with the best possible care and quality of life. Remember, each cat is unique, and their resilience and spirit often surprise us. With compassion, dedication, and advanced medical care, we can strive to provide the best outcomes for our feline friends facing kidney cancer.

If your cat has been diagnosed with kidney cancer or suspected kidney cancer, reach out to our Pet Advocate Team by phone at 833-PET-HERO or call 833-738-4376 as a totally complimentary service. Our extensively trained team is ready to assist you in understanding a diagnosis of renal cancer and offer essential information to guide you in making the most suitable treatment choice for your cat.