The kidneys are a pair of organs located just above the waist on either side of the backbone. Their job is to filter excess water and waste products from the blood. The water and waste drain from each kidney through a tube called a ureter to the bladder and are eliminated from the body as urine. The kidneys also produce substances that help control blood pressure and formation of red blood cells.
Several different types of cancer can develop in the kidney. Conventional or clear cell renal cell cancer, also known as renal cell carcinoma, is by far the most common type of kidney cancer in adults. Renes is the Latin word for kidney. Renal cell carcinoma accounts for about 85% of cancers arising from the kidney. Renal cell carcinoma develops in the tubules of the kidney, part of the filtering system.
Cancer occurs when normal cells undergo a transformation. During this transformation, the cells grow and multiply without normal controls.
As the cancer cells multiply, they form an area of abnormal cells.
As the cells continue to multiply, they form a mass called a tumor. (Tumors are not always cancer, but all the information about kidney tumors discussed in this article pertains to cancer.)
Tumors overwhelm surrounding tissues by invading their space and taking the oxygen and nutrients they need to survive and function.
Tumors are cancerous only if they are malignant—this means that, because of their uncontrolled growth, the tumors invade tissues of neighboring organs such as the liver, colon, or pancreas.
Cancer cells may also travel to remote organs via the bloodstream or the lymphatic system (a major part of the immune system consisting of organs and lymph vessels, ducts, and nodes that transport lymph from vessels through the bloodstream).
This process of invading and spreading to other organs is called metastasis. Renal cell carcinoma is most likely to spread to neighboring lymph nodes, the lungs, the liver, the bones, or the brain.
Each year, about 32,000 people in the United States are diagnosed with renal cell carcinoma. Of these diagnoses, most occur in people aged 50-70 years, but the disease can occur at any age. About twice as many men as women develop this cancer, and it occurs in all races and ethnic groups.
Like almost all cancers, renal cell cancer is most likely to be successfully treated when it is found early.
Circulatory System
Circulatory System, or cardiovascular system, in humans, the combined function of the heart, blood, and blood vessels to transport oxygen and nutrients to organs and tissues throughout the body and carry away waste products. Among its vital functions, the circulatory system increases the flow of blood to meet increased energy demands during exercise and regulates body temperature.
