Renal Medullary Carcinoma

Renal medullary carcinoma (RMC) is a rare type of kidney cancer that mostly affects people with sickle cell trait. Most people with RMC are under 30 years old, and it is twice as common in men than women. RMC usually starts from the right kidney but spreads to other organs before getting diagnosed.¹

Fewer than 5 percent of people with RMC live 3 years past diagnosis. It may be easier to treat RMC when diagnosed early. The most common symptoms of RMC are blood in the urine and pain on the kidney side. Treatment usually includes chemotherapy, surgery, or radiation therapy.²

What are the causes of renal medullary carcinoma?

We do not yet understand the causes of RMC. Nearly all people with RMC have a blood condition that causes red blood cells to sickle. This includes sickle cell disease, sickle cell trait, and other “sickle hemoglobinopathies.” There are no other known risk factors for RMC.^1,3

The majority of people with RMC have sickle cell trait. This may be because sickle cell trait is 50 times more common than other sickle hemoglobinopathies. About 1 in 14 Black people carry the sickle cell trait. About 1 in 20,000 to 40,000 people with sickle cell trait will develop RMC.^1,4

Tumors in people with RMC lack a certain protein, called INI1 (also called SMARCB1). This protein acts as a “tumor suppressor” by preventing healthy cells from turning into cancer cells. Sickled red blood cells in the kidney block blood flow to the innermost part of the kidney (the renal medulla). This may cause damage to the gene that is needed for kidney cells to produce the INI1 protein.³

What are the symptoms of renal medullary carcinoma?

Talk to your doctor as soon as possible if you experience any symptoms of RMC. The most common symptoms include:¹

• Blood in urine (hematuria)
• Pain on the kidney side
• A distinct mass on the right side
• Losing weight
• Fever and night sweats

An early diagnosis is important for better treatment outcomes. We are not yet able to prevent or screen for RMC. This is why it is important for people with SCD or sickle cell trait to be aware of these symptoms.²

How is renal medullary carcinoma diagnosed?

Diagnosing RMC early is difficult because there are no early symptoms. People with sickle cell trait who develop symptoms of RMC usually first undergo an ultrasound. This can help doctors visualize the kidneys. If they see a tumor, they can perform other imaging techniques to determine if it is cancerous. This includes computed tomography (CT) scan or magnetic resonance imaging (MRI).^1,2

If images show a kidney mass that may be cancerous, doctors will then perform a biopsy. This means they will take a small sample of the kidney tumor tissue. They will look at the tissue under a microscope and test it for the presence of INI1. A lack of INI1 will confirm a diagnosis of RMC.^1,2

How is renal medullary carcinoma treated?

Treatment of RMC may be done by doctors who treat cancer (oncologists) and kidney diseases (urologists). Specific treatments vary for every person, depending on factors such as:^1,2

• Disease stage
• Size of the tumor
• Symptoms
• How much the cancer has spread
• Age and general health
• Personal preference

Your doctors will discuss the potential benefits and risks of each treatment option with you. Talk to them about your priorities and ask them about possible side effects. RMC is often unaffected by chemotherapy treatments. Because of this, surgical removal of the kidney before the cancer has spread is the most successful. The most common treatments for RMC include:²

• Chemotherapy
• Surgery to remove the whole kidney
• Combination of chemotherapy and surgery
• Radiation therapy
• Other investigational treatments

Talk to your doctor about joining in a clinical trial for RMC treatments. For example, several ongoing clinical trials are testing treatments that use the body’s immune system to destroy RMC cells.^2,5-7