Kidney cancer shares some similar symptoms with kidney stones, including blood in the urine, lower back pain, and fatigue. Due to these similarities, some medical professionals may incorrectly diagnose kidney cancer as kidney stones.

Kidney cancer is one of the 10 most common cancers in people. Kidney cancer shares some symptoms with kidney stones, which are hard pieces of material that can form in one or both of the kidneys.

This article discusses the similarities between kidney cancer and kidney stone symptoms.

It also discusses how medical professionals sometimes incorrectly diagnose kidney cancer as kidney stones, and it explains the diagnosis methods for each condition.

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Kidney cancer and kidney stones share some similar symptoms. These similarities mean that it is possible for a doctor to misdiagnose kidney cancer as kidney stones.

Common symptoms of both kidney stones and kidney cancer include:

  • blood in the urine
  • severe pain on one side of the lower back
  • fever

One 2018 survey taken in the United Kingdom by a charity called Kidney Cancer UK stated that 45% of those with kidney cancer initially received an incorrect diagnosis. Of these people, 6% received an incorrect diagnosis of kidney stones.

A further 11% of those with kidney cancer in the survey received an initial incorrect diagnosis of a urine infection.

Q:

Can kidney stones be mistaken for another type of cancer?

Anonymous

A:

Symptoms of kidney stones, especially pain and fatigue, are also symptoms of cancers such as kidney cancer, colorectal cancer, and bladder cancer.

However, with a proper workup, including blood work, imaging, and a history of other symptoms, a medical team can assist in getting an accurate diagnosis.

Teresa Hagan Thomas, Ph.D., BA, RNAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

What are the other symptoms of kidney cancer?

Most kidney cancers do not cause symptoms in the early stages. If a person has a large kidney cancer, then they may experience symptoms early on.

Other signs and symptoms of kidney cancer include:

  • a lump on the side of the back or the lower back
  • fatigue
  • loss of appetite
  • weight loss
  • anemia

These signs and symptoms are often due to other diseases or health issues and are not always a sign that a person has cancer.

If a person has any of the symptoms above, then they should contact a doctor to receive a diagnosis.

If a person believes they have kidney cancer, then they should seek medical help right away. If a person receives a diagnosis for kidney stones but is concerned that they may have cancer, they should seek a second opinion.

Without treatment, kidney cancer can spread to other areas of the body.

Early treatment is key to improving a person’s outlook. If a person receives an incorrect diagnosis and the cancer spreads, then they are at an increased risk of death from the cancer.

A person’s 5-year relative survival rate is the likelihood that they will live for at least 5 years after their diagnosis compared to those without the condition.

The American Cancer Society (ACS) states that if a person receives a kidney cancer diagnosis before the cancer spreads to other areas of their body, they have a 93% chance of living for at least 5 years after the diagnosis.

However, if a person receives a kidney cancer diagnosis after the cancer has spread outside the kidney to nearby structures or lymph nodes, then their 5-year relative survival rate is 71%.

These statistics show the importance of receiving a correct diagnosis as early as possible to improve a person’s chances of survival.

If a person has had kidney stones, they may have an increased risk of developing kidney cancer.

One 2018 study included 120,852 participants and found that kidney stones contributed to an increased risk of kidney cancer.

A 2014 review analyzed seven studies to evaluate the association between a history of kidney stones and an increased risk of kidney cancer. The review concluded that there was an increased risk of kidney cancer in people who previously had kidney stones.

However, the study only noted this increased risk of kidney cancer in males.

According to the ACS, a doctor may first discuss a person’s medical history.

They may then carry out a physical examination. This is so they can look for signs of kidney cancer. For example, they may feel for an atypical mass or lump in the abdomen.

To confirm the diagnosis, a doctor will either look at a sample of kidney cells in a lab or use imaging tests to look at the kidney in detail.

Blood tests

These include:

  • Complete blood count (CBC): This is a test that measures the number of different cells present in a person’s blood. A person with kidney cancer may have anemia, which is a low red blood cell count. In some rare cases, a person with kidney cancer may have too many red blood cells. This is called polycythemia.
  • Blood chemistry test: This test measures the amount of certain chemicals in a person’s blood. This is an effective test because kidney cancer can cause the blood to contain high levels of liver enzymes and calcium. This test can also help a doctor measure kidney function.

These lab tests cannot fully confirm that a person has kidney cancer, but they can determine if a person has a problem related to their kidneys.

Imaging tests

Common imaging tests that a doctor may use to diagnose kidney cancer include:

  • Computed tomography (CT) scan: A CT scan uses a number of beams of radiation. This creates several X-rays, which can produce a detailed image of structures in the body.
  • Magnetic resonance imaging (MRI) scan: MRI scans can create detailed images of organs and other tissues within the body.
  • Ultrasound: An ultrasound can help detect a mass in the kidney and can show if it is solid or filled with fluid. Kidney tumors are more likely to be solid.
  • X-ray: A doctor may use an X-ray to look at blood vessels that feed a tumor or to see if the cancer has spread to other areas of the body.

Kidney biopsy

During a biopsy, a doctor will remove a sample of tissue or cells from the kidney. A pathologist then examines these cells under a microscope to see if cancer cells are present.

Biopsies are not as common when looking for kidney cancer because imaging tests often provide enough information for a doctor to make a diagnosis.

If imaging results are not clear enough, a doctor may use a biopsy to analyze a small piece of the kidney to see if cancer is present.

The National Institute of Diabetes and Digestive and Kidney Diseases states that a doctor will look at a person’s medical history before performing a medical exam. They may then use lab and imaging tests to confirm their diagnosis.

Lab tests

Common lab tests include:

  • Urinalysis: This test can show if a person’s urine has blood in it and can also detect minerals that may form kidney stones. This test can also rule out a urinary tract infection.
  • Blood tests: This test can see if there are high levels of certain minerals in a person’s blood. This is important, as high levels of certain minerals can lead to kidney stones.

Imaging tests

A doctor may also use imaging tests to help diagnose kidney stones. Common imaging tests for diagnosing kidney stones include:

  • X-rays: A doctor can use this imaging test to diagnose kidney stones and to see their location within the urinary tract.
  • CT scans: These scans can also show the size and location of a person’s kidney stones and see if the stone is blocking their urinary tract.

Kidney cancer shares some similar symptoms with kidney stones. Common symptoms that the two conditions share include blood in the urine, severe pain on one side of the lower back, and fever.

Due to these similarities, medical professionals sometimes incorrectly diagnose kidney cancer as kidney stones.

The longer a person has kidney cancer without receiving treatment, the more likely it is that the cancer will spread to other areas of the body. The farther a person’s cancer spreads, the worse their outlook is.

If a person believes they may have kidney cancer, then they should speak with a doctor. A person should seek a second opinion if they believe they may have cancer but their doctor has diagnosed kidney stones instead.