Diagnosis

Doctors use many tests to diagnose cancer and determine if it has metastasized. Some tests may also determine which treatments may be the most effective. For most types of cancer, a biopsy is the only way to make a definitive diagnosis of cancer. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may be used to find out whether the cancer has metastasized. Your doctor may consider these factors when choosing a diagnostic test:

• Age and medical condition
  
  
• The type of cancer suspected
  
  
• Severity of symptoms
  
  
• Previous test results

In addition to a physical examination, the following tests may be used to diagnose kidney cancer:

Blood and urine tests. A blood test to check the number of red blood cells, and a urine test to detect blood, bacteria, or cancer cells, may be performed. These tests may suggest that kidney cancer is present, but cannot make a definite diagnosis.

Biopsy. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. The sample removed during the biopsy is analyzed by a pathologist. Then the pathologist issues a pathology report (laboratory test results) that becomes a permanent part of the person’s medical record. Doctors must have a pathology report before they use radiation therapy or chemotherapy to treat the cancer. The pathology report identifies the type of cell involved in the kidney cancer, which is important in planning treatment. For instance, people with clear cell tumors have mutations of the Von Hippel-Lindau (VHL) gene (a tumor suppressor gene [a type of gene that prevents a tumor from growing]), making the cancer more likely to be treated with drugs that target the vascular endothelial growth factor (VEGF; see Treatment).

The type of biopsy performed depends on the location of the cancer. A separate biopsy may not be needed if the cancer is found on the CT scan and removal of the kidney is recommended. If surgery is recommended based on the results of other medical tests, such as the CT scan, many doctors will examine the tumor after it is removed during surgery, rather than a separate procedure beforehand. The patient should carefully discuss the reasoning for a recommended biopsy option with his or her doctor.

Imaging tests

Intravenous pyelogram (IVP). A dye is injected into the patient’s bloodstream to highlight the kidney, urethra, and bladder when an x-ray (see below) is taken. The picture produced can show changes in these organs and in the nearby lymph nodes.

Bone scan. A bone scan uses a radioactive tracer to look at the bones. The tracer is injected into a patient’s vein. It collects in areas of the bone and is detected by a special camera. Healthy bone appears gray to the camera, and areas of injury, such as those caused by cancer or a fracture (break), appear dark.

CT scan. A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail.

Magnetic resonance imaging (MRI). An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium may be injected into a patient’s vein to create a clearer picture.

Positron emission tomography (PET). A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive substance is injected into a patient’s body and absorbed by the organs or tissues being studied. This substance gives off energy that is detected by a scanner, which produces the images. Recent research studies suggest that PET scanning may be helpful to monitor tumor shrinkage during treatment of kidney cancer that has spread. However, it is still considered experimental, and health insurance does not often cover the scan because most types of kidney cancer do not absorb the radioactive substance.

X-ray. An x-ray is a picture of the inside of the body. For instance, a chest x-ray can help doctors determine if the cancer has spread to the lungs.

Cystoscopy/nephro-ureteroscopy. Rarely, a special test called a cystoscopy and nephro-ureteroscopy may be done for renal (kidney) pelvic cancer. During these procedures, the patient is sedated while a tiny, lighted tube is inserted into the bladder through the urethra and up into the kidney. The device can remove samples of cells and, in some cases, small tumors.

To learn more about what to expect during common diagnostic tests, read Cancer.Net: Tests and Procedures.

To learn about the terms used in this section, read the Cancer.Net Feature: Cancer Terms to Know: Newly Diagnosed.