Overview of Kidney Cancer
by Dr. C.H. Weaver M.D. updated 8/2019
In the United States, kidney cancer accounts for about 4% of all cancers and each year more than 61,000 people are diagnosed with kidney cancer. The most common type of kidney cancer is renal cell carcinoma (RCC), which starts in the lining of very small tubes (tubules) in the kidney. Kidney cancer occurs slightly more often in males and is usually diagnosed between the ages of 50 and 70 but can occur at any age. In adults, the most common type of kidney cancer is renal cell cancer. (1,2)
The kidneys are organs that are responsible for eliminating waste material from the blood by making urine. The kidneys also produce hormones, which regulate blood pressure and control red blood cell production. Most people have two kidneys and located just above the kidneys are the adrenal glands, which produce several essential hormones. Adrenal hormones help to regulate metabolism, blood pressure, inflammation, and response to stress. The adrenal glands also produce small amounts of sex hormones (androgens and estrogens).
Tiny tubules in the kidneys filter and clean the blood, remove waste products and make urine. Urine passes from each kidney through a long tube called a ureter into the bladder, which holds the urine until it passes through the urethra and leaves the body.
Renal cell cancer is a disease in which cancer cells develop in the cells lining the small tubules in the kidney. Cancer that starts in the ureters is different from renal cell cancer and is discussed in transitional cell cancer of the bladder.
The body can function perfectly well with one kidney and one adrenal gland if they are normal. This allows for the removal of one entire kidney and adrenal gland when necessary to remove a cancer localized to the kidney area. (1,2)
Symptoms & Signs of Renal Cell Cancer
Many kidney cancers go undetected due to the lack of symptoms and are incidentally detected during the medical evaluation of an unrelated problem. Kidney cancers can cause symptoms by compressing, stretching or invading structures near or within the kidney. Symptoms caused by these processes include pain (in the flank, abdomen or back) and blood in the urine (small amounts may not be visible). If cancer spreads beyond the kidney, symptoms depend upon which organ is involved.
- Blood in the urine.
- A lump in the abdomen
- A pain in the side or back that doesn’t go away.
- Loss of appetite.
- Weight loss for no known reason.
- Fatigue and anemia.
Sometimes a renal cell cancer causes associated clinical or laboratory abnormalities called para-neoplastic syndromes. These syndromes are observed in approximately 30% of patients with kidney cancer and can occur in any stage. Clinical symptoms include weight loss, loss of appetite, fever, sweats and high blood pressure.
Causes of Kidney Cancer
Renal cell cancer begins when healthy cells acquire a genetic change (mutation) that causes them to turn into abnormal cells. Most renal cell cancers develop sporadically, which means for no known reason.
Risk Factors for Kidney Cancer
A risk factor is anything that increases a person’s chance of developing cancer. Risk factors can influence the development of cancer, but most do not directly cause cancer. Many individuals with risk factors will never develop cancer and others with no known risk factors will. Some cancers however are more likely to develop in individuals with certain risk factors that increase an individual’s chance of developing cancer. The following factors may raise a person’s risk for developing renal cancer. (2-4)
- Overuse of certain pain medications for a long time.
- High blood pressure.
- A family history of renal cell cancer.
- Hereditary conditions
- Von Hippel-Lindau disease.
Diagnosis & Tests for Renal Cell Cancer
Doctors use many tests to find, or diagnose, cancer. They also do tests to learn if cancer has spread to other parts of the body from where the cancer originated. A biopsy is the only certain way to confirm a diagnosis of cancer. When performing a biopsy, the doctor takes a sample of tissue for testing in a laboratory.
When a kidney cancer is suspected, a kidney imaging study is obtained. The initial imaging study is usually an ultrasound or CT scan. If cancer is suspected, the patient should be evaluated to determine the extent of spread or stage of the cancer. Examination of both kidneys is essential to assure that one is working normally.
Staging of Kidney Cancer
When diagnosed with renal cell cancer further tests are necessary to determine the extent of spread (stage) of the cancer. Cancer’s stage is a key factor in determining the best treatment. The stage of cancer may be determined at the time of diagnosis or it may be necessary to perform additional tests.
Intravenous pyelogram (IVP): An IVP is a procedure which involves the injection of dye (contrast) into the blood. When the contrast travels through the kidneys and ureters, it allows these organs to be visualized with X-rays (fluoroscopy).
Ultrasound: A procedure in which high-energy sound waves (ultrasound) are bounced off internal organs and tissues and make echoes. The echoes form a picture of body tissues called a sonogram.
Imaging tests: Tests such as X-rays, CT scans, magnetic resonance imaging (MRI) and positron emission tomography (PET) are used to help determine the stage and whether the cancer has spread.
- Computed Tomography (CT) Scan: A CT scan is a technique for imaging body tissues and organs, during which X-ray transmissions are converted to detailed images, using a computer to synthesize X-ray data. A CT scan is conducted with a large machine positioned outside the body that can rotate to capture detailed images of the organs and tissues inside the body.
- Magnetic Resonance Imaging (MRI): MRI uses a magnetic field rather than X-rays, and can often distinguish more accurately between healthy and diseased tissue than a CT. An MRI gives a better picture of cancer located near bone than does CT, does not use radiation, and provides pictures from various angles that enable doctors to construct a three-dimensional image of the cancer.
- Positron emission tomography (PET): Positron emission tomography scanning is an advanced technique for imaging body tissues and organs. One characteristic of living tissue is the metabolism of sugar. Prior to a PET scan, a substance containing a type of sugar attached to a radioactive isotope (a molecule that emits radiation) is injected into the patient’s vein. The cancer cells “take up” the sugar and attached isotope, which emits positively charged, low energy radiation (positrons) that create the production of gamma rays that can be detected by the PET machine to produce a picture. If no gamma rays are detected in the scanned area, it is unlikely that the mass in question contains living cancer cells.
- Bone Scan: A test to check if there are cancer cells, in the bone. A very small amount of radioactive material is injected into a vein and travels through the bloodstream. The radioactive material collects in the bones and is detected by a scanner.
Precision Medicine & Personalized Cancer Care
Not all kidney cancer cells are alike. They may differ from one another based on what genes have mutations that are responsible for the growth of the cancer. Testing is performed to identify genetic mutations or the proteins they produce that drive the growth of the cancer. Once a genetic abnormality is identified, a specific targeted therapy can be designed to attack a specific mutation or other cancer-related change in the DNA programming of the cancer cells. Precision cancer medicine uses targeted drugs and immunotherapies engineered to directly attack the cancer cells with specific abnormalities, leaving normal cells largely unharmed. (5-8) Patients should discuss the role of genomic-biomarker testing for the management of their cancer with their treating oncologist.
Stages of Renal Cell (kidney) Cancer
Staging is ultimately confirmed by surgical removal of the cancer and exploration of the area adjacent to the kidney. The following are simplified definitions of the various stages of kidney cancer. Click on a stage for an overview of the most recent information available concerning the comprehensive treatment of renal cell cancer.
Stage I: The primary cancer is 7 centimeters (about 3 inches) or less and is limited to the kidney, with no spread to lymph nodes or distant sites.
Stage II: The primary cancer is greater than 7 centimeters (about 3 inches) and is limited to the kidney, with no spread to lymph nodes or distant sites.
Stage III: The cancer has spread to the regional lymph nodes but not to distant sites in the body, and/or extends to the renal veins or vena cava (large vein returning blood to the heart located in the middle of the abdomen near the back).
Stage IV: The cancer has spread to distant sites or invades directly beyond the local area.
Recurrent Renal Cell Cancer: Renal cell cancer has returned after primary treatment.
Ljungberg B, Campbell S and Cho H. The Epidemiology of Renal Cell Carcinoma. Eur Urol. 2011;60:615-621.
American Cancer Society. What is kidney cancer? Available from: https://www.cancer.org/cancer/kidney-cancer/about.html. Accessed July 2018.
Sene AP, Hunt L, McMahon RF, et al.: Renal carcinoma in patients undergoing nephrectomy: analysis of survival and prognostic factors. Br J Urol 70 (2): 125-34, 1992.
Golimbu M, Joshi P, Sperber A, et al.: Renal cell carcinoma: survival and prognostic factors. Urology 27 (4): 291-301, 1986. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 479-89.