Definition of Renal Cancer

Renal cancerRenal Cancer is the growth of a malignant (cancerous) tumor in the kidney.

Doctors diagnose about 30,000 people in the United States with renal cancer, also called kidney cancer, each year.

The most common form of renal cancer is renal cell carcinoma (RCC), which accounts for more than 90 percent of RCC among Americans.

Men are twice as likely as women to get renal cancer, and cigarette smokers (male or female) are two to four times as likely as nonsmokers to get renal cancer.

RCC arises from the epithelial cells that line the tubules within the nephrons.

A type of kidney tumor that occurs almost exclusively in children under age eight is Wilms’s tumor, also called nephroblastoma. Though Wilms’s tumor also arises from the tubules, its cells, course of growth, and treatment options are unique. Cancer from other sites may metastasize to the kidneys.

Staging of Renal Cancer

Renal Cancer StageExtent of CancerTreatment Protocols/Options
stage 1tumor remains confined to one site in one kidney and is 7 cm or smallerpartial or simple nephrectomy
stage 2tumor extends beyond the tissue capsule surrounding the kidney or is larger than 7 cmradical nephrectomy
stage 3tumor extends to adjacent lymph nodes or the veins that carry BLOOD from the kidneyradical nephrectomy
biological therapy
stage 4tumor extends to both kidneys or to other organs in the abdomen or to distant organs such as the LUNGS or BRAINpalliative surgery
palliative therapies
recurrenttumor returns after treatment, appearing either in the same kidney (when first cancer was stage 1), the other kidney, or another location in the bodyvaries according to previous treatment

Symptoms and Diagnostic Path

The earliest indication of renal cancer is hematuria (blood in the urine), which may be gross (enough blood is present to discolor the urine) or microscopic (the laboratory detects erythrocytes in the urine during examination of the urine sample under the microscope). Other symptoms may include

  • Lump or swelling in the central abdomen
  • Fatigue
  • Abdominal or back PAIN not related to injury
  • Unexplained or unintended weight loss
  • Edema (swelling due to retained fluid in the tissues), notably in the hands and feet

The diagnostic path begins with urine tests, blood tests, and abdominal ultrasound or computed tomography (ct) scan. Biopsy of the detected tumor confirms the diagnosis and provides information about whether the cancer has yet metastasized.

The pathologist assigns the cancer a stage based on the appearance and behavior of its cells. The cancer’s stage determines the appropriate treatment options and expected outcome of treatment.

Treatment Options and Outlook

Treatment depends on multiple factors including the person’s age, overall health status, and location and stage of the cancer. Doctors generally prefer surgery (nephrectomy) to remove the tumor (stage 0) or the kidney (all other stages). The nephrectomy may be segmental (removal of only the tumor and a small margin of healthy tissue), simple (removal only of the kidney), or radical (removal of the kidney, surrounding tissue, and adjacent lymph nodes).

Chemotherapy and radiation therapy are not very effective in treating renal cancer. Biological therapies such as interferons and interleukins, which stimulate the immune system to step up its attack against the cancer cells, are showing great promise in renal cancer.

The oncologist may use biological therapy after surgery for renal cancers that are stage 3 and 4. Some studies suggest a combination of biological therapy and chemotherapy may be more effective than biological therapy alone in some people. Treatment for recurrent renal cancer depends on how and where the cancer returns as well as on previous treatment.

Risk Factors and Preventive Measures

Cigarette smoking is the most identifiable, as well as preventable, risk for renal cancer. Other lifestyle factors that raise an individual’s risk for renal cancer include lack of physical exercise (sedentary lifestyle) and obesity.

Researchers believe obesity alters hormonal activity in the body in ways that facilitate the growth of renal cell carcinoma.

Other known risks for renal cancer include polycystic kidney disease, exposure to asbestos, exposure to heavy metals such as arsenic and cadmium, and industrial chemicals such as benzene and trichloroethylene. Renal cancer is also more common in people between the ages of 50 and 70, and in people who have a family history of renal cancer. The latter suggests genetic involvement, though researchers have yet to confirm evidence of this.


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