What is kidney cancer?
Cancer can start any place in the body. Kidney cancer starts in the kidney and is also called renal carcinoma (pronounced REE-nul CAR-sin-O-muh) or RCC for short. It starts when cells in the kidney grow out of control and crowd out normal cells. This makes it hard for the body to work the way it should.
Cancer cells can spread to other parts of the body. Cancer cells in the kidney can sometimes travel to the bone and grow there. When cancer cells do this, it’s called metastasis (pronounced meh-TAS-tuh-sis). To doctors, the cancer cells in the new place look just like the ones from the kidney.
Cancer is always named for the place where it starts. So when kidney cancer spreads to the bone (or any other place), it’s still called kidney cancer. It’s not called bone cancer unless it starts from cells in the bone.
Symptoms & Diagnosis
Small kidney cancer tumors don’t usually cause any signs or symptoms, but larger ones might. Symptoms of kidney cancer may be:
Blood in the urine (pee)
Low back pain on one side (not from a hit or fall)
A lump on the side or lower back
Urinalysis (YUR-in NA-lih-sis): Urine is checked in the lab to see if there are blood or cancer cells in it
Blood chemistry tests: These tests show how well the kidneys are working.
Complete blood count (CBC): This test measures the number of blood cells in the blood, like white blood cells, red blood cells, and platelets. People with kidney cancer often have low red blood cell counts. (This is called anemia [uh-NEE-mee-uh].)
Chest x-ray: X-rays may be done to see if the cancer has spread to your lungs.
CT or CAT scan: Uses x-rays to make pictures of your insides. This can show if the cancer has spread.
MRI scan: Uses radio waves and strong magnets instead of x-rays to make pictures. This test may be used to see if the cancer has spread.
PET scan: PET scans use a special kind of sugar that can be seen inside your body with a special camera. If there is cancer, this sugar shows up as “hot spots” where the cancer is found. This test can help show if the cancer has spread.
Ultrasound: Uses sound waves to make pictures of the inside of the body. This test can help show whether a kidney mass is solid or filled with fluid. (Kidney cancers are more likely to be solid.) If a kidney biopsy is needed, ultrasound can be used to guide a needle into the mass to take out some cells for testing.
Losing weight, if you’re not trying to lose weight
Fever that’s not from a cold and that doesn’t go away
Talk to a doctor if you notice any of these problems. Your doctor will ask you questions about your health and do an exam.
In a biopsy (BY-op-see), the doctor takes out a small piece of tissue to check it for cancer cells. A biopsy is the only way to tell for sure if you have cancer.
There are many types of biopsies. Ask your doctor what kind you will need. Each type has pros and cons. The choice of which type to use depends on your own case.
The stage of a cancer describes how far it has spread. Your treatment and prognosis (outlook) depend, to a large extent, on the cancer’s stage.
The stage is based on the results of the physical exam, biopsies, and imaging tests (CT scan, chest x-ray, PET scan, etc.), which are described in How is kidney cancer diagnosed?
There are actually 2 types of staging for kidney cancer:
The clinical stage is your doctor’s best estimate of the extent of your disease, based on the results of the physical exam, lab tests, and any imaging tests you have had.
If you have surgery, your doctors can also determine the pathologic stage, which is based on the same factors as the clinical stage, plus what is found during surgery and examination of the removed tissue.
If you have surgery, the stage of your cancer might actually change afterward (if cancer were found to have spread further than was suspected, for example). Pathologic staging is likely to be more accurate than clinical staging, because it gives your doctor a firsthand impression of the extent of your disease.
AJCC (TNM) staging system
A staging system is a standard way for the cancer care team to describe the extent of the cancer. The most common staging system for kidney cancer is that of the American Joint Committee on Cancer (AJCC), sometimes known as the TNM system. (Cancers that start in the renal pelvis have a different AJCC staging system, which is not described here.)
The TNM system describes 3 key pieces of information:
T indicates the size of the main (primary) tumor and whether it has grown into nearby areas.
N describes the extent of spread to nearby (regional) lymph nodes. Lymph nodes are small bean-sized collections of immune system cells to which cancers often spread first.
M indicates whether the cancer has spread (metastasized) to other parts of the body. (The most common sites of spread are to the lungs, bones, liver, brain, and distant lymph nodes.)
Numbers or letters appear after T, N, and M to provide more details about each of these factors. The numbers 0 through 4 indicate increasing severity. The letter X means “cannot be assessed because the information is not available.”
T categories for kidney cancer
TX: The primary tumor cannot be assessed (information not available).
T0: No evidence of a primary tumor.
T1: The tumor is only in the kidney and is no larger than 7 centimeters (cm), or a little less than 3 inches, across
T1a: The tumor is 4 cm (about 1½ inches) across or smaller and is only in the kidney.
T1b: The tumor is larger than 4 cm but not larger than 7 cm across and is only in the kidney.
T2: The tumor is larger than 7 cm across but is still only in the kidney.
T2a: The tumor is more than 7 cm but not more than 10 cm (about 4 inches) across and is only in the kidney
T2b: The tumor is more than 10 cm across and is only in the kidney
T3: The tumor is growing into a major vein or into tissue around the kidney, but it is not growing into the adrenal gland (on top of the kidney) or beyond Gerota’s fascia (the fibrous layer that surrounds the kidney and nearby fatty tissue).
T3a: The tumor is growing into the main vein leading out of the kidney (renal vein) or into fatty tissue around the kidney
T3b: The tumor is growing into the part of the large vein leading into the heart (vena cava) that is within the abdomen.
T3c: The tumor has grown into the part of the vena cava that is within the chest or it is growing into the wall of the vena cava.
T4: The tumor has spread beyond Gerota’s fascia (the fibrous layer that surrounds the kidney and nearby fatty tissue). The tumor may have grown into the adrenal gland (on top of the kidney).
N categories for kidney cancer
NX: Regional (nearby) lymph nodes cannot be assessed (information not available).
N0: No spread to nearby lymph nodes.
N1: Tumor has spread to nearby lymph nodes.
M categories for kidney cancer
M0: There is no spread to distant lymph nodes or other organs.
M1: Distant metastasis is present; includes spread to distant lymph nodes and/or to other organs. Kidney cancer most often spreads to the lungs, bones, liver, or brain.
Once the T, N, and M categories have been assigned, this information is combined to assign an overall stage of I, II, III, or IV. The stages identify cancers that have a similar prognosis (outlook) and thus are treated in a similar way. Patients with lower stage numbers tend to have a better prognosis.
Stage I: T1, N0, M0
The tumor is 7 cm across or smaller and is only in the kidney (T1). There is no spread to lymph nodes (N0) or distant organs (M0).
Stage II: T2, N0, M0
The tumor is larger than 7 cm across but is still only in the kidney (T2). There is no spread to lymph nodes (N0) or distant organs (M0).
Stage III: Either of the following:
T3, N0, M0: The tumor is growing into a major vein (like the renal vein or the vena cava) or into tissue around the kidney, but it is not growing into the adrenal gland or beyond Gerota’s fascia (T3). There is no spread to lymph nodes (N0) or distant organs (M0).
T1 to T3, N1, M0: The main tumor can be any size and may be outside the kidney, but it has not spread beyond Gerota’s fascia. The cancer has spread to nearby lymph nodes (N1) but has not spread to distant lymph nodes or other organs (M0).
Stage IV: Either of the following:
T4, any N, M0: The main tumor is growing beyond Gerota’s fascia and may be growing into the adrenal gland on top of the kidney (T4). It may or may not have spread to nearby lymph nodes (any N). It has not spread to distant lymph nodes or other organs (M0).
Any T, Any N, M1: The main tumor can be any size and may have grown outside the kidney (any T). It may or may not have spread to nearby lymph nodes (any N). It has spread to distant lymph nodes and/or other organs (M1).