Kidney Cancer

(Renal cell carcinoma; renal pelvic carcinoma; Wilms' tumor)

Kidney cancer is relatively uncommon in the United States, accounting for about 29,000 new cases and 12,000 deaths a year. In patients of all ages, males outnumber females about two to one. There are several types of kidney cancer; the most common are: Renal cell carcinoma, which most often originates in the nephrons, the filtering units of the kidney, and accounts for 85 percent of cases. This cancer can strike at any age, but it most common between ages 40 and 60. Cancer of the renal pelvis, which starts in the central part of the kidney, and frequently spreads to the ureter, the tube that carries urine from the kidney, and to the bladder. Wilms' tumor, a rare childhood malignancy, which usually occurs before the age of five years and often spreads to other abdominal organs. Wilms' tumor is quite different from adult kidney cancer. It produces a large abdominal swelling that grows rapidly. There may also be a low-grade fever, weight loss, fatigue, and other symptoms.

In adults, kidney cancer in its early stages usually does not produce symptoms, but may be detected during an examination for another problem. When symptoms do occur, they are often vague and misleading. As the cancer progresses, it may produce persistent flank pain, bloody urine, weight loss, fatigue, and malaise.

The cause of most kidney cancer is unknown, although heredity is thought to play a role. Cigarette smoking increases the risk of renal cell carcinoma, as does exposure to asbestos. Persons on long-term kidney dialysis also have an increased incidence of kidney cancer.

Diagnostic Studies and Procedures

Unexplained blood in the urine should prompt a doctor to investigate the possibility of kidney cancer, especially in an older adult. CT scanning is now the most accurate method of detecting the disease. In the past, an intravenous pyelogram -- X-rays taken after an iodine solution had been injected into the bloodstream -- was the major diagnostic study, and may still be ordered along with angiography, dye-enhanced X-rays of the renal blood vessels.

An ultrasonogram helps to differentiate between a fluid-filled cyst and a solid tumor. If a tumor is discovered, a biopsy will be necessary to find out if it is malignant; this is usually done by using a hollow needle to withdraw cells for laboratory analysis.

If kidney cancer is detected, additional CT scans will be done to determine whether or not it has spread to other parts of the body. At the time of diagnosis, about one-third of all renal cell carcinomas have already metastasized.

Procedures for diagnosing Wilms' tumor are essentially the same as those for adult kidney cancer. Because this cancer often spreads to the lungs, liver, and adrenal glands, the child may have to be hospitalized for special scans and liver studies.

Medical Treatments

Surgical removal is the usual treatment, most often a radical nephrectomy, in which the diseased kidney, surrounding fat and tissue, and nearby lymph nodes are excised. In 3 to 5 percent of cases, both kidneys are cancerous and must be taken out, necessitating at least two years of dialysis treatment. If there is no sign of cancer after that time, a kidney transplant may be considered.

Chemotherapy is sometimes used, especially if the cancer is inoperable or has metastasized, but only about 10 percent of patients improve with it. Radiation treatments are also of little use in treating adults. More benefit has been achieved with immunotherapy, in which vaccines and other substances are given to stimulate the immune system to fight the cancer. For unexplained reasons, metastatic tumors sometimes disappear after the diseased kidney has been removed.

Unlike adult kidney cancers, Wilms' tumor is highly treatable with a combination of surgery and chemotherapy. Recent studies show that 80 to 90 percent of children survive at least two years with this combined regimen, and many of these survivors are eventually cured. The younger the child at the time of diagnosis, the better the chance of a complete cure.

Alternative Therapies

Imagery and Visualisation. Because renal cell carcinoma often responds to anything that bolsters the immune system, these techniques may be especially beneficial. For added stress reduction, they are often combined with meditation and yoga.

Nutrition Therapy. Although diet has no impact on kidney cancer itself, dietary changes may reduce the risk of contracting it among people who have chronic kidney stones.

Self Treatment

Self-care is directed mostly to prevention. Do not smoke; this is especially critical. Wear a protective mask if you work with naphthalene, aniline dyes, and other potentially harmful gases or chemicals. Everyone with congenital kidney or urinary-tract abnormalities should undergo frequent screening examinations to detect possible kidney cancer in an early, more treatable stage.

Other Causes of Kidney Symptoms

Nephritis and other kidney infections can cause flank pain, bloody urine, and other symptoms similar to those of kidney cancer. Bladder and urinary-tract infections also cause such symptoms and sometimes mask kidney cancer.