What You'll Learn Here:
~ by Jo Jordan
Thirteen thousand Americans are expected to die in 2008 from kidney cancer.1 Over fifty-four thousand new kidney cancer cases are expected to develop this year.2
For decades, researchers have pointed to smoking as the major culprit when it comes to developing kidney cancer (also known as renal cancer). But recent research does not support smoking as the primary cause. While the incidence of kidney cancer has skyrocketed, smoking has not increased in proportion to the ever-growing number of renal cancer cases.
A study published in the Journal of the National Cancer Institute in 2006 reported that the incidence of kidney cancer in the United States had increased fifty-two percent between 1983 and 2002.3
Obesity combined with high blood pressure is now thought to be the interrelated cause of the growing number of kidney cancer cases.
Types of kidney cancer
Kidney cancer develops in various forms. There are three basic types:
- Renal cell cancer
- Transitional cell cancer
- Wilms’ tumor
Renal cell cancer (RCC) – also known as renal cell carcinoma, renal adenocarcinoma, or hypernephroma – manifests as several types:
- Clear cell
- Collecting duct
- Papillary (types 1 and 2)
The most common form of childhood kidney cancer is Wilms’ tumor; in adults it’s renal cell carcinoma.
What causes renal cancer?
While certain factors increase the risk of developing kidney cancer, it is unclear why, exactly, kidney cells become cancerous. Smoking – while still a risk factor – has not been found specifically to cause renal cancer. Furthermore, the incidence of smoking has not increased in proportion to the enormous increase in kidney cancer cases.
Some scientists suggest interrelated factors as the cause of kidney cancer. The University of Southern California’s Norris Comprehensive Cancer Center reports that a combination of obesity and high blood pressure are both associated with a process called lipid peroxidation, the byproducts of which result in DNA mutations that can trigger the formation of malignant cells.4
Environment, hereditary, and lifestyle factors may increase the likelihood of developing kidney cancer:
- Age – people between forty and sixty are at a higher risk
- Birt-Hogg-Dubé syndrome is associated with kidney cancer
- Bladder cancer patients are more likely to develop kidney cancer
- Dialysis or immunosuppressant drug use is linked to kidney cancer
- Environment – steel plant workers or those exposed to aniline dyes, asbestos, cadmium, heavy metals, or trichloroethylene are at a higher risk
- Gender – men are nearly twice as likely as women to be diagnosed with the disease
- Genetics – people with Von Hippel-Lindau disease or papillary renal cell carcinoma are at higher risk for developing kidney cancer
- High blood pressure and its treatments (diuretics) is linked to kidney cancer
- Ionizing radiation, used in X-rays and gamma rays, can cause cell damage that may lead to kidney cancer
- Obesity is associated with approximately one third of renal cell carcinomas
- Phenacetin, once used in pain relievers and taken off the market in the 1980s, has been linked to kidney cancer
- Smokers are more likely than non-smokers to develop the disease
- Tuberous sclerosis is associated with renal cell carcinoma
Kidney cancer symptoms
In the beginning, kidney cancer rarely makes its presence known with signs or symptoms.
In the latter stages, kidney cancer symptoms may include…
- A mass in the kidney area.
- Blood in the urine.
- Chronic back pain, just below the ribs.
- General fatigue.
- Intermittent fever; and/or unintentional weight loss.
The most common symptom of kidney cancer is painless – and often intermittent – urination of blood, which occurs in forty to fifty percent of patients.5
The key to kidney cancer survival
While there are some differences of opinion, many researchers believe that the chance of a full recovery from renal cancer is very good if the disease is caught in its early stages.
Renal cell carcinoma (RCC) is the most common type of kidney cancer. With early detection, the likelihood of RCC reoccurring is low.6 Unfortunately, the disease has few symptoms in its early stages, is usually undiagnosed or misdiagnosed, and is often not detected until the tumor has grown relatively large.
Because kidney cancer presents few symptoms, many cases are discovered accidentally during procedures for other diseases or conditions. As a result, fifteen to twenty-five percent of patients have metastatic kidney cancer at the time of diagnosis, meaning the cancer has spread to other areas of the body.7
Early detection can be key to survival because in its early stages, kidney cancer is likely to limit itself to the kidney. A five-year survival rate for people with cancer confined to the kidney is eighty-five percent or better. However, if the cancer has spread into the renal vein or the vena cava, the five-year survival rate is reduced to thirty-five to sixty percent.8
In addition to eliminating various risk factors by quitting smoking, controlling high blood pressure, and reducing exposure to environmental toxins, the key to prevention lies in diet and the maintenance of a healthy weight.
Individuals who are obese are at twice the risk of others for developing kidney cancer.9 Those who are merely overweight are thirty-five percent more likely to develop the disease than individuals at a healthy weight.10 For women, the production of estrogen triggered by fat cells increases the risk of developing kidney cancer.11
Diet and exercise are crucial
A high fiber, low animal fat diet that includes a variety of fruits, vegetables, and fish is recommended as a preventive against kidney cancer.
The Journal of the American Medical Association reported a seventy-four percent lower risk of developing kidney cancer for women who ate fish at least once a week in comparison to non-fish eaters.12
Kidney cancer patients are often deficient in vitamin D, so proper intake of foods containing vitamin D and/or a daily vitamin supplement may decrease the risk.
Regular daily exercise such as walking or cycling is recommended for optimal health, and to keep weight down.
For more information on healthy eating, dietary suggestions, weight loss, and fitness, check out our many articles:
- The Standard American Diet
- The Harmful Effects of Processed Foods
- Processed Food Facts
- Understanding The Dangers Of Trans Fats
- Why Is Fat So Vital?
- Ten Tips For Good Digestion
- Cleansing…The Puristat Way
- Seven Steps To Life-Long Weight Loss
Diagnosing renal cancer
A complete medical history and physical examination is the first step in diagnosing kidney cancer. Urine and blood tests determine how well the kidneys are functioning, as well as a check for high blood pressure.
Various technologies may be used by your health care provider to detect signs of cancer and/or tumors:
- Angiography – outlines blood vessels that supply a kidney tumor; they are different in appearance than healthy vessels
- Bone scan – small amounts of a radioactive material injected via a vein help to identify cancerous and non-cancerous diseases
- Chest X-ray – to determine whether or not cancer has spread to the lungs
- Computerized tomography – CT or CAT scans take cross-sectional X-ray images of internal organs
- Cystoscopy – examines the inside of the bladder and urethra using a thin, lighted instrument
- Excretory urogram – an X-ray of the urinary system
- Intravenous pyelogram (IVP) – dye is injected into a blood vessel to identify abnormalities in the kidney
- Magnetic resonance imaging – MRI scans use magnetization and radio waves to produce images of the internal organs
- Positron emission tomography – PET scans employ a three-dimensional scanning technology using injected, radioactive sugar to produce an image that illustrates how extensively a cancer has spread
- Tissue sample biopsy – confirms a solid tumor is cancerous vs. non-cancerous
- Ultrasonography/ultrasound – high-frequency sound waves are bounced off internal tissue, and their echoes converted into images
A kidney cancer diagnosis also includes determining the stage of the tumor:
- Stage I tumor: small, confined to kidney
- Stage II tumor: larger than stage I, confined to kidney
- Stage III tumor: has extended beyond kidney to surrounding tissue or adrenal glands, and/or may have spread to a nearby lymph node
- Stage IV cancer: has spread outside the kidney and/or to distant body parts
Treating kidney cancer
Depending on the stage of the disease, kidney cancer treatment options can involve one or a combination of the following treatment regimens:
Arterial embolization deprives the tumor of oxygen with an injection of blocking material into the kidney’s main blood vessel.
Chemotherapy, available in pill form, is used for patients with disease that has spread beyond the kidney.
Chemotherapy options include targeted therapy treatments. Designed to block signals that enable cancer to feed and grow, these drugs include sorafenib (Nexavar), sunitinib (Sutent), and temsirolimus (Torisel). Targeted drugs can be expensive, as well as cause side effects such as severe diarrhea, fatigue, and rash.
Cryoablation (freezing cancer cells) – gas-filled needles are inserted into a tumor to alternately freeze and thaw it; the repetition of this cycle causes cancer cells to die. Pain may be experienced after the procedure.
Immunotherapy drugs such as interferon or interleukin-2 are administered in order to stimulate the immune system to fight off cancer.
Radiation therapy – beams of high-energy X-rays are used in conjunction with surgery and as an alternative treatment. Radiation therapy is sometimes used for pain relief when cancer has spread to the bones.
Surgery – options are nephrectomy (removal of the entire kidney), removal of only the tumor, or a laparoscopic procedure vs. open surgery. In laparoscopic surgery, the insertion of a tiny camera through a small incision, as well as several additional small incisions, enables the surgeon to operate.
Recent studies suggest that though survival rates are equal, removing only the tumor (rather than the entire kidney) sometimes decreases the chance of renal failure.
A brighter future for kidney cancer patients
In 2004, the Action to Cure Kidney Cancer organization (ACKC) reported that there were more than two hundred thousand kidney cancer survivors living in the United States.13
The new knowledge that has come to light about the way in which interrelated causes such as obesity and high blood pressure may work contribute to the development kidney tumors may help health conscious individuals avoid kidney cancer altogether.
With ongoing research that seeks to further pinpoint the exact cause of the disease, advances in diagnostic and surgical procedures, and new treatment and drug therapies, more and more kidney cancer patients are being given the opportunity to live relatively normal lives for many, many years to come.