Kidney cancer has some similar symptoms to kidney stones, including blood in the urine, back pain, and fatigue. Because of these similarities, some medical professionals may misdiagnose kidney cancer as kidney stones.
Kidney cancer is one of the 10 most common types of cancer in humans. Kidney cancer shares some symptoms with kidney stones, which are hard pieces of material that can form in one or both kidneys.
This article describes the similarities between kidney cancer and kidney stone symptoms.
It also explains how medical professionals sometimes misdiagnose kidney cancer as kidney stones and explains the diagnostic methods for each condition.
Kidney cancer and kidney stones have similar symptoms. These similarities mean that a doctor can misdiagnose kidney cancer as kidney stones.
Common symptoms of kidney stones and kidney cancer include:
- blood in the urine
- severe pain on one side of the lower back
A 2018 UK survey by a charity called Kidney Cancer UK found that 45% of kidney cancer patients were initially misdiagnosed. Of these people, 6% received an incorrect diagnosis of kidney stones.
Another 11% of those with kidney cancer in the survey received an initial incorrect diagnosis of a urinary infection.
What Are the Other Symptoms of Kidney Cancer?
Most kidney cancers do not cause symptoms in the early stages. When a person has a large kidney cancer, they can show symptoms early on.
Other signs and symptoms of kidney cancer include:
- a bun at the side of the back or lower back
- loss of appetite
- weight loss
These signs and symptoms are often due to other illnesses or health problems and are not always a sign that a person has cancer.
If a person has any of the above symptoms, they should consult a doctor for a diagnosis.
If a person thinks they have kidney cancer, they should seek medical help immediately. If a person is diagnosed with kidney stones but is concerned 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 is misdiagnosed and the cancer spreads, there is an increased risk of dying from cancer.
A person’s 5-year relative survival rate is the likelihood that they will live at least 5 years after their diagnosis compared to those without the disease.
The American Cancer Society (ACS) states that a person who receives a diagnosis of kidney cancer before the cancer spreads to other areas of their body has a 93% chance of living at least 5 years after diagnosis.
However, if a person is diagnosed with kidney cancer after the cancer has spread outside of the kidney to nearby structures or lymph nodes, then their 5-year relative survival rate is 71%.
These statistics highlight the importance of getting a correct diagnosis as early as possible to improve a person’s chances of survival.
If a person has had kidney stones, they may be at an increased risk of developing kidney cancer.
A 2018 study involved 120,852 participants and found that kidney stones contributed to an increased risk of kidney cancer.
A 2014 review analyzed seven studies to assess the association between a history of kidney stones and an increased risk of kidney cancer. The review concluded that people who had previously had kidney stones were at an increased risk of kidney cancer.
However, the study found this increased risk of kidney cancer only in men.
According to the ACS, a doctor may first discuss a person’s medical history.
They can then perform a physical exam. This allows them to check 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 either looks at a sample of kidney cells in a laboratory or uses imaging tests to look at the kidney in detail.
- 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 have 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.
Common imaging tests that a doctor may use to diagnose kidney cancer include:
- Computed tomography (CT) scan: A CT scan uses a series of beams of rays. This creates multiple X-rays that can create a detailed image of structures in the body.
- Magnetic resonance imaging (MRI): MRI scans can create detailed images of organs and other tissues in the body.
- Ultrasonic: An ultrasound can help detect a mass in the kidney and can show whether it’s solid or fluid-filled. Kidney tumors tend to be solid.
- Roentgen: A doctor can use an X-ray to examine blood vessels supplying a tumor or to see if the cancer has spread to other areas of the body.
During a biopsy, a doctor removes a sample of tissue or cells from the kidney. A pathologist then examines these cells under a microscope to see if cancerous 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 the imaging results aren’t clear enough, a doctor can 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 examines a person’s medical history before conducting a medical exam. They can then use laboratory and imaging tests to confirm their diagnosis.
Common laboratory tests include:
- urinalysis: This test can show if a person’s urine contains blood and can also detect minerals that can form kidney stones. This test can also rule out a urinary tract infection.
- blood tests: This test can determine if certain minerals are high in a person’s blood. This is important because high levels of certain minerals can lead to kidney stones.
A doctor can also use imaging tests to diagnose kidney stones. Common imaging techniques used to diagnose kidney stones include:
- X-rays: A doctor can use this imaging test to diagnose kidney stones and see their location in 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 has some similar symptoms to kidney stones. Common symptoms shared between the two conditions include blood in the urine, severe pain on one side of the lower back, and fever.
Because of these similarities, medical professionals sometimes misdiagnose kidney cancer as kidney stones.
The longer a person has kidney cancer without treatment, the more likely it is that the cancer will spread to other areas of the body. The further a person’s cancer spreads, the worse their outlook.
If a person thinks they may have kidney cancer, they should talk to a doctor. A person should get a second opinion if they think they have cancer but their doctor has diagnosed kidney stones instead.