Testing can show if a kidney tumor is benign (not cancer) or malignant (cancerous). If it is cancer, we’ll find out the type of tumor and make a treatment plan that’s best for you. When we have an accurate diagnosis, we can be sure you get the most effective treatment.
Imaging tests help us see inside your kidneys to look for cancer. Our kidney cancer experts often diagnose a kidney mass by repeating imaging tests that were done elsewhere. Our expertise can help you avoid a biopsy or surgery.
There are many kinds of imaging tests, including:
- CT scan: This test uses x-rays to take pictures of the body. To limit your exposure to radiation, we do this test only when necessary. We often use a contrast dye given intravenously (through an IV) to see the tumor better.
- Ultrasound: This test can tell if a mass in the kidneys is a fluid-filled cyst or a solid tumor.
- MRI scan: This test uses magnetism, not radiation, to make cross section images of your kidneys and adrenal glands.
- Cystoscopy: We place a small tube with a lens into your urethra (thin tube that carries urine from the bladder). This test lets us see your urethra and bladder.
- Ureteroscopy: We pass a narrow, lighted tube through your urethra and into the bladder, a ureter, and the renal pelvis.
We may recommend you get a kidney biopsy so we can tell if a tumor is cancerous.
During a biopsy, doctors remove a tiny piece of tissue from a tumor, usually through a hollow needle. A pathologist will then look at the sample under a microscope to see the cell types.
If the cells are cancerous, the pathologist will do more tests on the tissue to tell the type of kidney cancer.
The results of a kidney biopsy give us important information. They help us give you an accurate cancer diagnosis. The results also tell us whether you need more care, and options for surgery and medication.
Staging is how we describe how far cancer has advanced in the organ where it started, and whether it spread. We stage kidney cancer based on several things. This includes the size of the tumor, and the structures in and outside the kidney that are involved. We see if cells left the kidney and started to grow somewhere else, such as a lymph node or another organ.
- Stage 1 tumors are smaller than 7 centimeters at their widest diameter (about the size of an egg). They are only in the kidney.
- Stage 2 tumors are more than 7 centimeters. They are only in the kidney.
- Stage 3 tumors go through the renal capsule (the membrane on the outer surface of the kidney). They can extend into the fat and blood vessels around the kidneys, and in some patients they may involve nearby lymph nodes.
- Stage 4 includes tumors in nearby organs or ones that spread to distant lymph nodes or other body parts. If the cancer has formed separate tumors in structures outside the kidney, it’s called metastatic disease.
Nearly 2 out of every 3 people with kidney cancer are diagnosed when they have stage 1 or 2 disease. About 15 to 20 percent are diagnosed when they have stage 3 disease. Around 15 to 20 percent are diagnosed with stage 4 disease. The 5-year survival rate is about 80 percent for all stages combined, but it varies greatly by stage.
Doctors gather information to predict how likely it is the cancer will advance and to choose the best treatment. They use information from mathematical models and lab test results. They also use details about the tumor, such as its stage, size, grade, and type.