Renal Medullary Carcinoma

Renal medullary carcinoma (RMC) is a rare, aggressive form of kidney cancer. Fewer than 1 out of 100 people worldwide with kidney cancer have this rare type. Most people diagnosed are young Black males with sickle cell trait or sickle cell disease.

Currently, there’s no cure for renal medullary carcinoma. It spreads fast, and it’s challenging to treat. Researchers continue to study new cancer treatments that can slow the progression of this cancer.

Symptoms of renal medullary carcinoma

Renal medullary carcinoma symptoms include:

• Blood in your pee (usually the first presenting symptom)
• A lump or mass where your kidneys are (your lower back, just below your ribcage)
• Pain where the affected kidney is (for most people, it’s the kidney on the right side)
• Fever
• Night sweats
• Unexplained weight loss

Renal medullary carcinoma causes

Doctors don’t know what causes renal medullary carcinoma. But they do know that it involves a change (mutation) in the SMARCB1 gene. SMARCB1 is a tumor suppressor gene. Normally, this gene stops cancerous tumors from forming. When a mutation happens in this gene, the gene stops working, allowing tumors to grow unchecked.

Almost everyone with renal medullary carcinoma has sickle cell trait or sickle cell disease. This suggests a connection between the sickle cell conditions and RMC. With sickle cell, you inherit abnormal genes that cause your red blood cells to be sickle-shaped instead of round. The abnormal shape can prevent red blood cells from flowing freely through your tissues and supplying them with oxygen.

One theory is that with RMC, the sickle cells get trapped in the renal medulla (inner part of your kidney). This keeps them from delivering oxygen to the area, causing the tissue to die. The tissue death can damage cells and genes, allowing cancer-causing gene mutations.

But more research is needed before scientists know the full relationship between RMC and sickle cell.

Risk factors

The biggest risk factor for developing renal medullary carcinoma is having sickle cell trait or sickle cell disease. Other factors associated with RMC risk include your:

• Age: RMC is more common in teens and young adults (from ages 11 to 39).
• Sex: Males are 2 to 3 times more likely to develop RMC.
• Race: Most people diagnosed with RMC (and sickle cell) in the U.S. are Black.

How doctors diagnose this condition

If your healthcare team thinks you might have RMC, they’ll do imaging tests to check for tumors in your kidney. The most commonly used tests are CT scans and MRIs. They’ll also check for signs of cancer spread. This typically involves getting a full-body CT scan or a PET scan. Most renal medullary carcinomas have already spread by the time they’re diagnosed.

Your care team will do a biopsy to check for cancer cells. This involves using a needle to collect a tissue sample from the tumor. A pathologist will examine the tissue in a lab to check for RMC.

How is renal medullary carcinoma treated?

RMC treatment usually starts with chemotherapy. Chemotherapy uses drugs to kill cancer cells. Your healthcare provider may also recommend surgery. They may remove the affected kidney (nephrectomy) and nearby lymph nodes to slow cancer spread. You may need surgery to relieve symptoms.

Your provider may recommend that you take part in a clinical trial. Clinical trials test the safety and effectiveness of new treatments. For example, some clinical trials for renal medullary carcinoma are testing the effectiveness of chemotherapy treatment alongside newer treatments called targeted therapy and immunotherapy.

Your provider can explain the benefits and risks associated with your treatment options.

What is the prognosis for renal medullary carcinoma?

The life expectancy of a person with renal medullary carcinoma used to be fewer than six months. With recent treatment advancements, more people are living longer. The median survival rate for RMC after diagnosis is 12 months. A median is the midway point. This means that about half the people die within the year of their diagnosis. The other half live past a year.

Still, although the prognosis isn’t good, nothing is certain. Ultimately, your healthcare provider is your best resource for explaining what to expect.