Cancer cells can break away from a primary tumor and spread through the lymphatic system or blood vessels and grow in another part of the body. This is called metastasis. Metastasis can occur with any malignant tumor, including kidney cancer.
When cancer cells break off and form a secondary tumor, the new tumor is called a metastatic tumor. Although the tumor is in a different part of the body, its cells are like those in the original tumor. This means that if kidney cancer metastasizes to the lung, the tumor in the lung is still a form of kidney cancer and is not lung cancer.
Metastasis commonly occurs in the later stages of cancer. The most typical secondary cancer sites are the:
In metastasis, malignant cells attach to and break down the proteins of the extracellular matrix (ECM), the material that surrounds cells. ECM is basically the connective tissue that comprises our bodies. Once the cancer cells have broken through the ECM, they can enter the lymph system or blood vessels and travel to different areas of the body.
In advanced kidney cancer, metastasis occurs when the cancer has spread from the primary tumor to other parts of the body. In most cases, when kidney cancer metastasizes, it spreads to any of the following:
Metastasis is more common with kidney cancer than with many other cancer types because the disease can grow and advance for a long time without presenting any symptoms.
Although the exact cause is still unknown, there are certain risk factors that can increase your likelihood of developing kidney cancer. These include:
The most common type of kidney cancer is called renal cell carcinoma (RCC), which affects approximately three in 10,000 people. This means that in the United States alone there are 32,000 new cases of RCC each year. Each year, approximately 12,000 people will die from RCC. RCC mostly affects men between the ages of 50 and 70.
Because kidney cancer can advance without presenting any initial symptoms, it's possible that a diagnosis may occur only after it has metastasized. Oftentimes, if a doctor detects a metastasis and cannot find the site of the primary tumor, it is located in either the lung or kidney.
Initial symptoms of kidney cancer can include:
Many other symptoms may appear due to metastasis of the kidney cancer. These can include:
Treatment options for metastatic cancer can vary widely based on the following:
Treatments may be used alone or in conjunction with other treatments and include:
Chemotherapy has not been proved to be an effective treatment for kidney cancer and, therefore, is rarely used alone, although it may be used in combination with another treatment.
Unfortunately, prognosis is not good for people who have metastatic kidney cancer. The five-year survival rate is less than 5 percent if the cancer has spread to other organs and is only 5 percent to 15 percent if the cancer has metastasized to the lymph nodes.
Cancer Research UK (2007). Advanced Kidney Cancer. Retrieved July 11, 2007, from the Cancer Research UK Web site: http://www.cancerhelp.org.uk/help/default.asp?page=4044#what.
DeGroot, Henry III, MD. (n.d.) Renal Cell Carcinoma - Metastasis to Bone. Retrieved July 11, 2007, from the BoneTumor.org Web site: http://www.bonetumor.org/tumors/pages/page64.html.
Medical Encyclopedia (2005). Renal Cell Carcinoma. Retrieved July 11, 2007, from the Medical Encyclopedia Web site: http://www.nlm.nih.gov/medlineplus/ency/article/000516.htm.
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