Renal medullary carcinoma is a rare type of kidney cancer. It develops most often in male Black Americans under age 35. It’s highly associated with genes linked to sickle cell disease.
About
Doctors still have a limited understanding of renal medullary carcinoma because it’s so rare. Almost everyone who develops it has genes associated with sickle cell disease, suggesting there’s a strong genetic component.
Renal medullary carcinoma tends to be highly aggressive and difficult to treat. Treatment usually aims at reducing symptoms and prolonging life.
Read on to learn more about this rare type of kidney cancer, including symptoms, how it’s treated, and its outlook.
Renal medullary carcinoma is a rare but aggressive type of kidney cancer. It develops in a part of the kidney called the medulla. The medulla is the innermost part of the kidney. Its main function is to maintain the blood’s water and salt balance.
Renal medullary carcinoma cells lack a protein called INI1 or SMARCB1. This protein is a tumor suppressor. It normally helps prevent cells from becoming cancerous.
About 70% of cases of renal medullary carcinoma occur in the right kidney.
Is renal medullary carcinoma curable?
Renal medullary carcinoma is rarely curable. Only about 5% of people have cancer contained in one kidney when they receive a diagnosis.
Treatment for cancer that has spread to distant areas tends to focus on reducing symptoms and prolonging life rather than trying to cure the cancer.
The first signs and symptoms of renal medullary carcinoma may include:
- blood in urine
- flank pain
- loss of appetite
- unexplained weight loss
- fever
- abdominal mass
- low red blood cell count
- swelling in your lower body
Metastatic renal medullary carcinoma
Renal medullary carcinoma often spreads to bone or the lungs.
If it spreads to your bones, you might experience:
- bone pain
- easily fractured bone
- spinal cord compression, which can include:
- back or neck pain
- muscle weakness
- numbness and tingling in arms and legs
- high blood calcium (hypercalcemia), which can cause:
- muscle weakness
- muscle and joint aches
Lung metastasis can cause symptoms such as:
Risk factors for renal medullary carcinoma include:
- sickle cell disease, which is seen in almost all people with renal medullary carcinoma
- sub-Saharan African heritage
- being ages 9–35 years
possibly high intensity exercise, if you have a gene associated with sickle cell disease
Sickle cell disease and renal medullary carcinoma
About 1 in 14 Black Americans have an inherited gene linked to sickle cell disease. This disease causes sickle-shaped red blood cells that tend to stick together and have trouble carrying oxygen.
Between 1 in 20,000 and 1 in 39,000 Black Americans develop renal medullary carcinoma.
Experts think the sickle shape of blood cells might block the blood supply of the renal medulla and damage the INI1 gene within cells. This gene helps suppress the formation of cancer.
Researchers have also found the risk of developing renal medullary carcinoma is increased in other countries, such as Greece, where sickle cell disease is most common in other races and ethnicities.
Treatment options for renal medullary carcinoma include:
- surgery, which might include:
- radical nephrectomy for cancer limited to the kidney
- cytoreductive nephrectomy for cancer spread to distant areas
- removal of surrounding lymph nodes
- a combination of chemotherapy drugs, such as:
- methotrexate, vinblastine, doxorubicin, and cisplatin
- paclitaxel with cisplatin or carboplatin
- clinical trials of new treatments, such as:
targeted therapy drugs - immunotherapy
- vascular endothelial growth factor-directed therapies
Renal medullary carcinoma tends to have a poor outlook.
In a 2023 study, researchers reported an average survival of 13.8 months among 100 people diagnosed in the United States from 1996–2018. Approximately 70% of people included in the study had cancer spread to distant organs when they received their diagnosis.
Researchers found Black Americans were less likely to receive surgery and five times more likely to die than white Americans. Researchers note the reasons why are unclear and yet to be investigated. However, racism and healthcare inequities may play a role.
Only about 5% of people receive a diagnosis with renal medullary carcinoma when it’s still limited to the kidney.
Kidney cancer survival rates
The table below shows the
The 5-year relative survival rate is a measure of how many people with a condition are alive 5 years later compared with people without the condition.
| Stage | 5-year relative survival rate |
|---|---|
| localized | 93% |
| regional | 72% |
| distant | 15% |
| all stages | 77% |
Renal medullary carcinoma is a rare type of cancer that develops in the innermost part of the kidney. Almost all people who develop it carry genes for sickle cell disease. In the United States, most cases occur in Black Americans under 35 years old.
Doctors are still figuring out how to best treat renal medullary carcinoma. The outlook remains poor, but new treatment options, such as immunotherapy and targeted therapy drugs, are under investigation.