Renal cell carcinoma can spread by growing into nearby tissue and traveling through lymph nodes or blood vessels. It most often metastasizes to the lungs, but other common sites include the bones, liver, and lymph nodes.

Renal cell carcinoma (RCC) is the most common type of kidney cancer. It accounts for most kidney cancers, with thousands of people newly diagnosed each year in the United States.

In RCC, a single tumor usually grows in one kidney. However, two or more tumors can grow in one kidney or in both kidneys simultaneously.

Many people with RCC may have metastasis at the time of diagnosis, which means the cancer spreads from the kidney or kidneys to another area of the body.

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RCC develops in the kidneys, where cancer cells grow out of control and form a mass called a tumor.

There are different types of RCC, including clear cell RCC and non-clear cell RCC.

Clear cell RCC is the most common type, and it accounting for roughly 80% of metastatic RCC cases. The cells forming this type of RCC appear clear or pale under a microscope.

According to the National Cancer Institute (NCI), cancer can metastasize to other areas of the body through a series of steps. These include:

  • growing into nearby tissue
  • passing through the walls of nearby blood vessels or lymph nodes
  • moving through the bloodstream and lymphatic system to other areas of the body
  • stopping in small blood vessels in distant areas of the body, growing in the walls of the blood vessels, and invading surrounding tissue
  • growing in this tissue until the cells form a tumor
  • causing new blood vessels to grow, which supply the metastatic tumor with blood and help it to grow

Metastatic RCC most often spreads to the following sites:

  • lungs
  • lymph nodes
  • bones
  • liver
  • adrenal glands
  • brain
  • pancreas

How fast RCC spreads varies between individuals.

Factors that can influence the speed of metastasis include:

  • The subtype: The subtype of RCC a person has can influence the speed of metastasis. Most people with metastatic RCC have clear cell subtypes, which can be aggressive, meaning it grows or spreads quickly.
  • The grade: The grade of the cancer refers to how closely the cancer cells resemble normal cells. Cancer cells with a higher grade are more likely to grow faster and more aggressively.
  • Genetics: Certain genetic mutations may cause faster metastasis.
  • Tumor size: Larger primary tumors may cause RCC to spread more quickly.

The rates of RCC spread differ between people. A 2021 study discussed various findings of the growth rates of clear cell carcinomas, which included growth rates of:

  • 0.09 cm per year to 0.86 cm per year
  • 0.15 cm per year to 0.31 cm per year
  • 8.06 cm per year

The size and extent of the tumor may be an indication of the stage of the cancer. As tumors grow larger, they may grow into nearby areas and metastasize. Other times, the tumor may be any size, but cancer cells may travel to lymph nodes or other areas of the body.

Metastatic cancer does not always cause symptoms. If symptoms do occur, they may vary depending on the size and location of the metastatic tumors.

According to the NCI, some common symptoms of metastatic cancer include:

  • shortness of breath when cancer has spread to the lung
  • fractures and pain when cancer has spread to the bone
  • swelling in the belly and jaundice when cancer has spread to the liver
  • dizziness, headaches, and seizures when cancer has spread to the brain

Treatment for metastatic RCC varies depending on the size of the primary tumor, the number of metastases, and the structure of the cancer tissue.

Doctors typically do not treat metastatic RCC with traditional chemotherapy. Instead, treatment may involve:

  • Surgery: Surgeons may remove cancerous tissue, where possible, including part of the kidney in a partial nephrectomy, or the entire kidney, in a radical nephrectomy.
  • Immunotherapy: Immunotherapy helps a person’s immune system heal the body from illnesses, such as cancer.
  • Targeted therapy: Targeted therapies are medications that target cancer cells and do not affect normal cells. The medications stop cancer from growing and spreading.

Research has found that combining immunotherapy and targeted therapy can improve the survival rate in people with metastatic RCC.

Treatment for bone and brain metastases

When RCC has spread to the bones or brain, it may be more difficult for doctors to treat.

Doctors may treat bone metastases with a tyrosine kinase inhibitor (TKI) drug called cabozantinib. TKIs work by blocking tyrosine kinase enzymes, which stop cancer cells from growing.

Doctors may also treat brain metastases with cabozantinib or with other treatments, which include:

  • Other kinase inhibitors: These include sunitinib, sorafenib, and temsirolimus.
  • Nivolumab: This drug blocks certain cancer cell proteins, allowing immune T cells to more effectively kill the cancer cells.

According to the American Cancer Society (ACS), the 5-year relative survival rate for a person with metastatic RCC is 18%. This means a person with metastatic RCC is 18% as likely as a person without the condition to be alive 5 years after diagnosis.

A person’s outlook can depend on various factors, such as their age and general health, the extent of the cancer, the size of the primary tumor, and the site of the metastases.

People who develop pancreatic or lung metastasis may have a more positive outlook than those who develop brain, bone, or liver metastasis.

About one-third of people with renal cell carcinoma experience metastasis.

RCC most often metastasizes to the lungs, bones, and lymph nodes. It also commonly spreads to the liver, adrenal glands, and pancreas.

However, a person may not have symptoms of metastatic RCC. If symptoms do present, they may include shortness of breath when metastases are in the lung, bone pain and fractures when cancer spreads to the bone, and jaundice and swelling in the belly when metastases are in the liver.

Treatment may involve surgery, immunotherapy, and targeted therapy.