What Is Kidney Cancer in Dogs, and What Can I Do About It?

Finding out your dog might have kidney cancer is a lot to take in. Whether you noticed blood in their urine, felt something unusual in their belly, or your vet flagged something on a routine scan, you’re probably looking for real answers right now.

Here’s what’s actually happening, what to expect, and how to move forward.

Signs and symptoms of kidney cancer in dogs

Kidney tumors often don’t cause obvious symptoms until they’ve been growing for a while. By the time signs appear, the tumor may already be fairly large.

• Blood in the urine (hematuria): One of the most common early signals. The urine may look pink, red, or brownish. Any blood in urine warrants a same-day vet call.
• Weight loss: Gradual, unexplained weight loss without a change in diet. Combined with any other symptom on this list, don’t wait.
• Lethargy: Less energy, less interest in walks or play, sleeping more than usual. Easy to attribute to aging, worth investigating in an older dog with any other symptom.
• Abdominal mass: A lump you might feel in the belly, or visible swelling on one side. See a vet within 24 hours if you notice this.
• Loss of appetite: Picking at food or eating much less than normal alongside other symptoms warrants a prompt vet visit.
• Increased thirst and urination: Often a sign that kidney function is being affected.
• Weakness or difficulty walking: Can occur if the tumor has spread to other areas. Treat as urgent alongside other symptoms.

If your dog is showing one or more of these signs, especially blood in the urine combined with weight loss or a belly mass, don’t wait on a vet visit.

What causes kidney cancer in dogs

There’s no single clear cause. Kidney cancer is more common in middle-aged to older dogs (typically seven years and up), and some breeds appear more often in cases, including German Shepherds and Golden Retrievers. But it can happen in any dog.

Tumor types your vet might mention:

• Renal cell carcinoma: The most common type. A malignant tumor that starts in the lining of the kidney’s filtering tubes. Typically affects one kidney and is the type most likely to be treated with surgery.
• Renal adenocarcinoma: A subtype of renal cell carcinoma, originating in the kidney’s glandular tissue. Often used interchangeably with renal cell carcinoma in clinical settings.
• Nephroblastoma: A rarer tumor that develops from embryonic kidney cells. More often seen in younger dogs.
• Lymphoma and transitional cell carcinoma: Other cancers that can involve the kidneys, though they originate elsewhere.

Diagnosis: what to expect at the vet

Your vet will likely start with bloodwork and a urinalysis to look for blood, abnormal cells, and how well the kidneys are filtering. From there, imaging is the next step.

An abdominal ultrasound uses sound waves to create a picture of the organs inside the belly. It’s non-invasive and can clearly show a tumor’s size, location, and whether it’s affecting one or both kidneys. For context on what a dog ultrasound typically costs, that’s worth knowing before your appointment. Chest X-rays may also be taken to check for metastasis to the lungs.

To confirm the tumor type, your vet may recommend a biopsy, where a small sample of tissue is collected and examined under a microscope. This can sometimes be done with a needle guided by ultrasound, or it may happen during surgery itself. The biopsy result shapes the entire treatment plan.

Stages of kidney cancer in dogs and treatment options

Staging refers to how far the cancer has progressed. In general terms:

• Early stage: Tumor confined to one kidney, no spread detected.
• Mid stage: Tumor may have grown larger or begun to affect nearby tissue.
• Advanced or end stage kidney cancer in dogs: Cancer has spread to lymph nodes, lungs, liver, or other organs. At this point, the focus typically shifts from cure to quality of life.

When the cancer is localized to one kidney and hasn’t spread, your vet will likely recommend a nephrectomy, which is the surgical removal of the affected kidney. This is often the most effective treatment and can be curative if the cancer is caught before metastasis occurs. Chemotherapy and radiation have limited proven benefit for renal cell carcinoma in dogs, but your vet or a veterinary oncologist (a cancer specialist) can walk you through options based on your dog’s specific situation.

Living with one kidney: what a nephrectomy actually means for your dog

Can my dog really live normally with just one kidney? The answer, in most cases, is yes.

Dogs, like humans, are born with two kidneys but only need one to function well. As long as the remaining kidney is healthy, it compensates remarkably well over time. Many dogs go on to live comfortable, active lives after a nephrectomy.

What recovery looks like:

• Hospital stay of a few days post-surgery for monitoring
• Activity restriction for several weeks while the incision heals
• Follow-up bloodwork and urinalysis to check how the remaining kidney is handling the extra load
• Possible dietary adjustments, like a kidney-supportive diet, to reduce strain on the single kidney long-term

Ongoing monitoring is important. Your vet will likely recommend regular check-ins every few months in the first year, with bloodwork each time. This is good maintenance, not a reason to panic. For more on stages of kidney disease and what kidney health monitoring involves, that’s worth reading.

Kidney cancer in dogs: life expectancy and the euthanasia question

Life expectancy depends heavily on whether the cancer has spread. Dogs whose tumors are caught early and removed surgically before metastasis can sometimes have survival times of a year or more, with some reports of dogs doing well for several years post-surgery. When metastasis is already present at diagnosis, the prognosis is shorter, often measured in weeks to a few months.

The question of when to consider euthanasia is one of the hardest any pet owner faces. Signs that most vets use to guide that conversation:

• Your dog is no longer eating or drinking, even with medication to stimulate appetite
• Pain is present and not manageable with available options
• They’ve lost interest in things they used to love: walks, play, interaction
• They’re having more bad days than good days

Talk openly with your vet about quality-of-life scoring tools they can use with you. You don’t have to make this call alone, and there’s no shame in asking for guidance.

Does pet insurance cover kidney cancer in dogs?

Treatment for kidney cancer, including abdominal ultrasound, biopsy, nephrectomy, and follow-up care, can add up quickly. Surgery alone can run several thousand dollars, and ongoing monitoring adds to that over time.

Kidney cancer in dogs is covered under a Lemonade Pet accident and illness policy, as long as it’s not pre-existing and develops after the 14-day illness waiting period has passed. If your dog is already showing symptoms or has been diagnosed, coverage for that condition won’t apply. If your dog is healthy right now, that’s the best time to get covered.

Before we go

Kidney cancer in dogs is a serious diagnosis, and it’s okay to feel scared or overwhelmed. But there’s real reason for measured hope, especially when the cancer is caught early and confined to one kidney. Surgery works. Dogs adapt. And with the right monitoring, your dog can still have a good quality of life ahead.

Talk to your vet, ask every question you have, and if you haven’t looked into pet insurance yet, now’s a good time.

Frequently Asked Questions

A few quick words, because we <3 our lawyers: This post is general in nature, and any statement in it doesn’t alter the terms, conditions, exclusions, or limitations of the policies issued, which differ according to your state of residence. You’re encouraged to discuss your specific circumstances with your own professional advisors. The purpose of this post is merely to provide you with info and insights you can use to make such discussions more productive! Naturally, all comments by, or references to, third parties represent their own views, and Lemonade assumes no responsibility for them. Coverage may not be available in all states. Please note that statements about coverages, policy management, claims processes, Giveback, and customer support apply to policies underwritten by Lemonade Insurance Company or Metromile Insurance Company, a Lemonade company, sold by Lemonade Insurance Agency, LLC.  The statements do not apply to policies underwritten by other carriers.