Kidney cancers are tumors that start growing inside the kidney. Cells begin to grow out of control, multiplying in huge numbers. These cells can build up to form a mass, or tumor, within the kidney.

The Centers for Disease Control and Prevention (CDC) say that renal cell cancer is the most common type of kidney cancer affecting adults in the United States.

In this article, we will look at the likelihood of renal cell cancer spreading to other parts of the body, as well as the possible areas of the body to which it may spread. We will also explain what symptoms to look for and what to expect from treatment.

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According to the American Cancer Society (ACS), renal cell carcinoma (RCC) accounts for about 90% of kidney cancer diagnoses among adults in the U.S. The most common subtypes of RCC are clear cell, papillary, and chromophobe.

In an article published in the World Journal of Oncology, scientists explain that the clear cell subtype is both the most common and the most aggressive, or fast-growing, kind of RCC. Clear cell RCC accounts for 75% of diagnoses.

The article authors state that clear cell RCC is most likely to spread, or metastasize, to the lungs, liver, or bones. Chromophobe RCC, which accounts for 5% of diagnoses, spreads in only 7% of cases.

The National Kidney Foundation explains that many people do not have symptoms in the early stages of RCC and that people may receive a diagnosis after getting tests for something else. An article in the Asian Journal of Urology says that by the time doctors diagnose RCC, it will have spread in approximately one-third of cases.

The subtype of RCC plays a significant role in how fast this cancer grows and spreads, according to an article in the World Journal of Oncology. The article authors explain that genetic factors may also be important.

For example, nonhereditary, or somatic, mutations in the von-Hippel-Lindau gene account for 45% of clear cell RCC cases. However, it is important to note that this is not a von-Hippel-Lindau syndrome — it is a one-off mutation in that particular gene. Von-Hippel-Lindau disease itself accounts for 5% of cases.

Other general risk factors include:

  • Age: RCC typically affects older people.
  • Sex: RCC is more common in males than females.
  • Race: The article authors note that African American, Hispanic American, and Native American people have a greater risk of RCC; African Americans have a reduced chance of recovering from RCC; and there is increased incidence of RCC among Hispanic and Native American populations. Healthcare inequities may be one reason for these disparities.
  • Weight: Scientists have noted a consistent link between a high body mass index and RCC.
  • Blood pressure: High blood pressure, or hypertension, can damage the kidneys and increase the risk of kidney cancers. According to the journal, high blood pressure almost doubles the risk of developing RCC.

The ACS explains that RCC starts in the linings of tiny tubes, called tubules, inside the kidneys. Cells multiply out of control and build up in a mass, or tumor, in the kidney.

Cancer cells can spread through the body in different ways, according to the National Cancer Institute (NCI). These include:

  • growing into, or invading, nearby tissue
  • invading the walls of nearby blood vessels or lymph nodes
  • traveling through blood vessels or lymph nodes to other parts of the body

Researchers continue to investigate the biomechanics of what makes RCC metastasize, but it seems to follow certain patterns. Places RCC may spread to include the:

  • lungs, which are the most common site of metastasis, accounting for 45% of cases
  • bones
  • lymph nodes
  • liver
  • pancreas
  • adrenal glands
  • brain

Ongoing research and new treatment options are increasing survival rates, according to a report published in the Journal of Oncology Practice. The results of trials show that the average survival time is more than 4 years.

In a 2020 trial, the median survival rate was a little over 48 months in groups with intermediate or poor risk. Some people experience better outcomes.

The site of the metastasis does impact survival rates, and people with lung-only or pancreatic metastasis may have a more favorable outlook than those with bone, liver, or brain metastasis.

The ACS estimates that the 5-year survival rate in the years 2011–2017 for people with metastatic RCC was 13%. However, this has likely improved with the development of new treatments.

The ACS notes that treatment for RCC depends on whether the cancer has spread to other parts of the body, as well as the size of the original tumor.

Depending on the cancer tissue structure and the number of metastases, a person may receive surgery to remove affected areas, as well as either the whole kidney (radical nephrectomy) or the affected part of the kidney (partial nephrectomy).

Traditional chemotherapy is not typically effective in metastatic RCC. Instead, combinations of immunotherapy and other targeted substances have become the main treatment for many people, even those with widespread metastases.

Additionally, a 2021 study found that a combination of immunotherapy and targeted therapy improved the survival rates for people with RCC.

Active surveillance

Doctors may consider some people for active surveillance (AS). This means they will closely monitor a person’s condition without starting treatment. Doctors may choose to do this when a person is diagnosed with a condition but does not have any symptoms.

For example, researchers in a 2016 trial carefully selected 48 people to undergo AS, and those people did not require active treatment for just under 15 months. Individuals may discuss AS with their doctor to establish whether it could be appropriate for them.

The psychological impact of having any cancer can be enormous and can correlate to a poor outcome, according to a study published in the journal Therapeutic Advances in Urology.

Some oncology services work alongside counselors that have specific experience working with people who have received a cancer diagnosis. A person might consider exploring this option to help better manage their mental health.

According to the NCI, relaxation and breathing techniques can help with stress and depression that may come about after a cancer diagnosis or during cancer treatment.

Practical concerns, such as travel to and from appointments and unexpected costs, can increase the burden on someone with RCC. The ACS explains that help is available and suggests some ways to find it.

Clear cell renal cell cancer is the most common form of kidney cancer in the U.S. that can spread to other parts of the body. It is more common among older people.

To treat the cancer, doctors may initially recommend active surveillance before starting treatments such as surgery and combination therapies. However, this may depend on where and how much the cancer has spread.

Researchers continue to investigate the disease and potential treatment options.