Every year, about 62,800 cases of kidney cancer occur, and about 14,300 people die from this disease annually. Most of the people affected by this disease are older individuals, and the average age at which most people are diagnosed with cancer of the kidney is 64. This disease which is sometimes referred to as renal cancer is rare in people under 45 years.
Definition & Facts
Kidney cancer is a disease characterized by an abnormal growth of cells in the kidney tissue. As time goes, these cells form a tumor. The disease first appears in the lining of the kidney tubules. Kidneys are bean-shaped organs placed below the rib cage near the center of the back. Healthy individuals have two kidneys, and each one is the size of a fist.
Kidneys have four primary functions. They control blood pressure, eliminate waste products, maintain fluid balance, produce hormones required for making the bones strong. Usually, cancer begins when something induces changes in the cells and they start to divide out of control. A malignant tumor can metastasize, that is, spread to other organs and tissues.
Symptoms & Complaints
- Blood in urine (hematuria)
- A lump or chunk in the kidney area
- Loss of appetite
- Weight loss
- Bone pain
- Pain on one side
- High blood pressure
- Anemia (not having sufficient red blood cells)
- Fever that lasts several weeks in the absence of a cold or any other infection
- Swollen ankles and swollen knees
If it spreads to other parts of the body, it may cause other symptoms such as:
The exact etiology of kidney cancer is unknown, but there are several known risk factors. A risk factor is a characteristic or behavior that increases a person’s chances of developing the disease. Risk factors include:
- Smoking—there is strong evidence suggesting that smoking cigarettes, cigars, and pipe double a person’s risk of renal cancer. Research indicates that 26 to 30 percent of kidney cancer cases are directly associated with smoking.
- Overuse of painkillers—phenacetin, an active compound in some of the over-the-counter painkillers once commonly used, is linked to kidney cancer, especially in people who used these drugs in excess. Although it was removed from the US market about 20 years ago, older individuals who used it may be at high risk of kidney cancer
- Exposure to chemicals—studies show that exposure to some substances may increase the probability of developing renal cancer. Cadmium, formerly an ingredient in certain paints and inks, and asbestos, once used as an insulation material, are linked to kidney cancer. Thus, the people exposed to these environmental toxicants such as shipyard and construction workers, printers and painters, are at a higher risk of renal cancer.
- Genetics—people with a family history of renal cancer are at an increased likelihood of kidney cancer. It is thought that genetic mutations may be the cause of this disease, and this may be triggered by damage to the DNA that is responsible for gene formation. Cigarette smoke also contains chemicals that damage the genes in the kidney cells
- Age—renal cancer is common in individuals aged 50 to 70
- Extended dialysis—patients under long-term dialysis treatment may develop cysts in their kidneys, and this can cause renal cancer
- Diet and weight—obesity and a high-fat diet put an individual at a higher risk of renal cancer
- Gender—men are twice more likely to develop renal cancer than women
- Estrogen—animals in the lab have been shown to develop kidney cancer after being given estrogen
Diagnosis & Tests
An early diagnosis of this disease is vital. If a doctor suspects kidney cancer, a series of lab tests, exams, and procedures are done to confirm the diagnosis. The physician will do a meticulous physical examination to assess the patient’s health and obtain information about the patient’s symptoms. The doctor will also take the patient’s medical history to determine the presence of risk factors for kidney cancer.
One or more imaging tests will be done to obtain pictures and locate the anomalies. Some imaging tests involve the injection of a tracer material (a low-level radioactive isotope or a dye) into the bloodstream of the patient. The tests include:
- Anemia—insufficient number of red blood cells caused by internal bleeding, a common symptom of cancer
- Polycythemia—excess red blood cells sometimes produced by cancerous tumors in the kidney that induce the production of erythropoietin (EPO), a hormone that causes an increase in the production of red blood cells in the bone marrow
- Hypercalcemia—excess calcium levels in the blood and elevated liver enzymes
A cytoscopy may also be performed to rule out blood in the urine caused by other health problems such as traumatic kidney injury or kidney stones. A needle biopsy will collect tissue from the kidney for lab analysis.
Treatment & Therapy
The treatment of renal cancer depends on the type of cancer, grade and stage of the tumor, patient’s overall health, and age. Surgery is the most common treatment for kidney cancer, and there are several surgical options which include simple nephrectomy in which the doctor only removes one kidney, partial nephrectomy where the doctor just removes part of the kidney with the tumor, and radical nephrectomy in which the doctor removes the whole kidney together with the adrenal gland and other tissues around the kidney
Sometimes, arterial embolization is used before surgery. In this procedure, a small tube is inserted into the blood vessels in the groin, and it is moved through the blood vessel until it reaches the kidney. A unique substance is then injected through this catheter to block the renal artery (the main blood vessel of the kidney). This denies the cancer cells oxygen and other substances they require to grow.
Surgery is suitable for most kidney cancer stages. But, at stage IV when cancer has spread beyond the kidney, chemotherapy and biological therapy may be used. Chemotherapy uses medications to stop or kill the growth of the cells while biotherapy uses the body’s own immune system to combat the cancer. Hormone therapy involves using hormones to control and inhibit the growth of the cancer cells.
Prevention & Prophylaxis