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What Is Kidney Cancer?

Kidney cancer, also known as renal cell carcinoma, is cancer that begins in the kidneys when cells begin to grow out of control. The kidneys are bean-shaped organs located on both sides of the spine behind the other abdominal organs. The main job of kidneys is to remove excess water, salt, and other waste from the blood. The waste that is filtered by the kidneys becomes urine that collects in the center of each kidney in the renal pelvis and exits the kidneys through tubes called ureters. These tubes lead to the bladder.  

According to the American Cancer Society, Kidney cancer is among the 10 most common cancers among men and women, with men (one in 46) being twice as likely as women (one in 80) to be diagnosed. Kidney cancer is more common among African Americans and American Indian/Alaska Natives. The median age of people diagnosed with kidney cancer is 64. The American Cancer Society estimates about 79,000 new cases of kidney cancer, about 50,290 in men and 28,710 in women, are diagnosed and about 13,920 people, 8,960 men and 4,960 women, die from the disease every year. 

Renal cell carcinoma is the most common type of kidney cancer in adults, making up about nine out of every 10 kidney cancers diagnosed. Although rare, a solid kidney cancer tumor called Wilms tumor is the third most common type of solid tumor affecting children.

→ Research supports the practice of personalized treatment to improve fertility outcomes for pediatric kidney cancer patients

Kidney cancer rates have been rising since the 1990s; however, death rates have remained stable. One explanation for the increased number of cases diagnosed is the use of computerized tomography (CT) scans and other imaging techniques that can detect cancers that might have never been found otherwise.

Why Come to CU Cancer Center for Kidney Cancer 

The CU Cancer Center is the only National Cancer Institute (NCI) Designated Comprehensive Cancer Center in Colorado and one of four in the Rocky Mountain region. Our doctors provide world-class, patient-centered care and have access to cutting-edge treatments not available at most other medical centers in the country. A multidisciplinary team can open the door for more treatment options, clinical trials, and a well-rounded care plan.

The CU Cancer Center is a member of the National Comprehensive Cancer Network (NCCN) advisory panels. The NCCN establishes guidelines for the diagnosis and treatment of all cancer types. Doctors all across the United States and throughout the world for use these guidelines as a reference.

The University of Colorado is a Von Hippel-Lindau (VHL) Alliance Clinical Care Center, recognized for dedication to a team approach and for additional depth of expertise and experience in treating VHL patients who have kidney and other VHL-associated tumors.

The CU Cancer Center offers kidney cancer patients the expertise of a team specializing in kidney cancer care, as well as cutting edge research through clinical trials that give patients more treatment options. Patients at the University of Colorado also have the added benefit of the entire institution and the collection supportive oncology teams behind them in their fight to overcome cancer.

Our clinical partnership with UCHealth has produced survival rates higher than the state average for all stages of kidney cancer and other urologic cancers.

Kidney Cancer Graph

Number of Patients Diagnosed – UCHealth 693 – State of Colorado 2,870
Number of Patients Surviving – UCHealth 495 – State of Colorado 1,949
*n<30, 5 Year Survival – (Date of diagnosis 1/1/2010–12/31/2014)

Types of Kidney Cancer

Renal cell carcinoma is the most common type of kidney cancer. Renal cell carcinoma usually occurs as a single tumor in a kidney, or two or more tumors in one or both kidneys. There are several subtypes of renal cell carcinoma, determined by the appearance of the cells from a biopsy. The renal cell carcinoma subtype determines the course of treatment for the patient.

There are two main types of kidney cancers; clear cell renal cell carcinomas and non-clear cell renal cell carcinomas.

Clear cell renal cell carcinoma is the most common subtype of renal cell carcinoma with seven out of 10 people with renal cell carcinoma having clear cell carcinoma. Under a microscope, clear cell renal cell carcinoma cells appear pale with clear cytoplasm.

Non-clear cell renal cell carcinomas have multiple subtypes, of which papillary renal cell carcinoma and chromophobe renal cell carcinoma are the most common.

  • Papillary renal cell carcinoma is the second most common subtype of renal cell carcinoma, about one in 10 cases. These cancers appear finger-like.
  • Chromophobe renal cell carcinoma accounts for about 5% of renal cell carcinomas. Like clear cell renal cell carcinoma, the cells of these cancers can be pale but are usually larger. 

Rare types of renal cell carcinoma subtypes make up less than 1% of renal cell carcinomas.

  • Collecting duct renal cell carcinoma.
  • Multilocular cystic renal cell carcinoma.
  • Medullary carcinoma.
  • Mucinous tubular and spindle cell carcinoma.
  • Neuroblastoma-associated renal cell carcinoma.

Other types of cancers can occur in the kidneys, but have a different biology than renal cell carcinoma and are treated differently.

Transitional cell carcinomas, also known as urothelial carcinomas, account for 5% to 10% of cancers in the kidneys. Transitional cell carcinomas start in the lining of the renal pelvis, which is made up of cells called transitional cells. These cells appear similar to cells found in the ureters and the bladder. Cancers that develop in the transitional cells look and behave like other urothelial carcinomas and are treated similar to bladder cancer.  

Wilms tumor (nephroblastoma) occurs almost exclusively in children. They are the most common type of kidney cancer in children, making up about nine in 10 cases. 

Renal sarcoma is a rare type of cancer that begins in the blood vessels or connective tissues of the kidneys. It accounts for less than 1% of kidney cancers. 

Benign kidney tumors

Some kidney tumors are non-cancerous, meaning they do not metastasize or spread to other areas of the body and are easily treated by removal. 

Angiomyolipomas are the most common type of benign kidney tumor. Angiomyolipomas are made up of different types of connective tissues (blood vessels, muscle, fat) and are more prevalent in women. 

Oncocytomas are uncommon benign kidney tumors that can grow large and are more prevalent in men.

Causes of Kidney Cancer

Kidney cancer occurs when deoxyribonucleic acid (DNA) gets damaged or mutates (changes). DNA is a molecule in the cells that make up genes. Genes provide instructions to the cells, telling them when to grow, divide, and die. Kidney cancer forms when a cell’s DNA is damaged or altered, and the cells continue to grow and divide out of control where they aren’t needed.

Genetic mutations can be inherited or acquired. Inherited gene mutations run in families and increase the risk of developing kidney cancer. Acquired gene mutations are changes that occur over the course of a person’s lifetime and are not passed on. Most cases of kidney cancer are acquired DNA mutations rather than inherited.

Most cases of kidney cancers are acquired rather than inherited. The most common inherited kidney cancer is Von Hippel-Lindau (VHL) syndrome. VHL disease is caused by mutation of VHL, a tumor suppressing gene that would normally help keep cells from growing uncontrollably. When a VHL gene is mutated, it leads to the build-up of abnormal proteins that lead to abnormal cell growth. VHL syndrome is also associated with hemangioblastomas of the brain and spinal cord, pancreas tumors, in addition to kidney tumors. In 2021, the FDA approved Belzutifan (Welireg) for treatment of VHL-associated tumors.

Other inherited conditions can lead to the development of kidney cancer:

  • Hereditary leiomyomata and renal cell carcinoma (HLRCC) is caused by changes in the fumarate hydratase (FH) gene. Patients with HLRCC have papillary type II renal cell carcinoma, as well as leiomyomatosis in the skin and uterus.
  • Birt-Hogg-Dube syndrome is an inherited condition in which patients have kidney cysts and kidney cancers in additions to skin tumors and lung cysts. Birt-Hogg-Dube syndrome is caused by mutations in the FLCN gene that creates a protein call folliculin.
  • Hereditary papillary renal cell carcinoma (type I papillary RCC) is caused by alteration of the MET oncogene.

Some genetic tests can detect gene mutations associated with inherited syndromes. It is recommended to seek genetic testing and genetic counseling if there is a family history of kidney cancers linked to these syndromes.

Latest in Kidney Cancer from the CU Cancer Center

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Information reviewed by Elaine Lam, MD, in February 2022.