Kidney Cancer

What is kidney cancer?

Kidney cancer is the abnormal growth of cells in your kidney tissue. In time, these cells form a mass called a tumor. Cancer begins when something triggers a change in the cells, and they divide out of control. This type of cancer is most common in people between the ages of 65 and 74. Men are twice as likely as women to develop the disease. It’s also more common in Native American and Black populations.
Kidney cancer is much less common in children. However, 500 to 600 children are diagnosed with a Wilms tumor (a type of kidney cancer) every year in the United States.

Types

Renal cell carcinoma (RCC): This is the most common form of kidney cancer in adults and accounts for 85% of all kidney cancers. Renal cell carcinoma usually develops as a single tumor in one kidney, but it can affect both kidneys. The cancer begins in the cells that line your kidney’s tubules (tiny tubes that return nutrients and fluid back to your blood). The most common type of RCC is clear cell renal cell carcinoma (ccRCC).

Transitional cell cancer: Transitional cell carcinoma accounts for 6% to 7% of all kidney cancers. This cancer usually begins in the area where your ureter connects to the main part of your kidney. This area is called your renal pelvis. Transitional cell carcinoma can also occur in your ureters or bladder.

Renal sarcoma: This is the least common form of kidney cancer, accounting for only 1% of kidney cancer cases. It begins in the connective tissues of your kidneys and, if not treated, can spread to nearby organs and bones.

Wilms tumor: This is the most common type of kidney cancer in children. It accounts for about 5% of kidney cancers.

Symptoms

Kidney cancer doesn't usually cause symptoms at first. In time, signs and symptoms may develop, including:

Blood in the urine, which may appear pink, red or cola colored.
Loss of appetite.
Pain in the side or back that doesn’t go away.
Tiredness.
Unexplained weight loss.

Causes (and risk factors)

The exact cause of renal cell cancer is unknown. However, there are certain risk factors that are linked to it. These risk factors, according to the ACS, are as follows:

Smoking. Smoking increases the risk of kidney cancer. The risk seems related to the amount you smoke.
Asbestos. Studies show a link between exposure to asbestos and kidney cancer.
Cadmium. There may be a link between cadmium exposure and kidney cancer. Cadmium may increase the cancer-causing effect of smoking.
Family history. Family history of kidney cancer increases a person’s risk.
Gender. Men are twice as likely to develop renal cell cancer than women.
Von Hippel-Lindau syndrome. This is a disease caused by a gene mutation that increases the chances of renal cell cancer.
Birt-Hogg-Dube syndrome. Patients who have this disease are more likely to develop renal cell cancer.
Other hereditary syndromes. Patients with hereditary papillary renal cell carcinoma, hereditary leiomyoma-renal cell carcinoma, and hereditary renal oncocytoma are more likely to develop kidney cancer.
Obesity. Obesity increases a person’s risk of kidney cancer.
Advanced kidney disease. Patients with advanced kidney disease who have been on dialysis for a long time may develop renal cell cancer.
High blood pressure. Patients who have high blood pressure have a higher risk for kidney cancer.
Diuretics (water pills). Drugs that eliminate excess body fluid may raise the risk of kidney cancer, although this is not clear.
Race. African-Americans have a slightly higher risk of kidney cancer.

Staging

Stage I: The kidney tumor is less than 7 centimeters (2.8 inches) and has not spread.
Stage II: The kidney tumor is greater than 7 centimeters (2.8 inches) and has not spread.
Stage III: The tumor (any size) is in the kidney and nearby lymph nodes or in the blood vessels and surrounding kidney tissue.
Stage IV: The cancer has spread to lymph nodes, other organs or to the adrenal gland above the kidney.

Grade

The grade of a cancer describes how much the cancer cells resemble normal cells, which helps doctors understand how the cancer might behave and what treatment is needed. In kidney cancer, clear cell and papillary renal cell cancers are graded from 1 to 4, with grade 1 being the most similar to normal cells (low grade) and grade 4 being the most abnormal (high grade). Low grade cancers tend to grow slowly and are less likely to spread, while high grade cancers grow more quickly and are more likely to spread. Chromophobe renal cell cancer does not currently have a standard grading system.

A specialist called a pathologist determines the grade by examining the cells under a microscope, focusing on changes in the cell’s nucleus. The more abnormal the cells look, the higher the grade assigned. However, while grade provides important information about the behavior of the cancer, the main factor in deciding treatment is the stage—whether the cancer has spread beyond the kidney or not.

5-Year Survival Rate

At a glance:

Estimated new cases in 2024	80,980
% of all new cancer cases	4.0%
Estimated deaths in 2024	14,510
% of all cancer deaths	2.3%
5-year relative survival (2014–2020)	2.3%