Kidney Cancer: Overview and More

Kidney cancer includes several different diseases, although renal cell carcinoma is the most common type. Historically, the most common signs have been symptoms of flank pain (pain in the side and lower back), abdominal mass, and blood in the urine, but today these are often discovered by chance when perform imaging tests for another condition. CT is the most common diagnostic test, although other imaging tests may be done.

Kidney cancer is unique in that surgery can be done even with advanced tumors. Both targeted therapy and immunotherapy drugs can be used, and chemotherapy and radiation therapy play less of a role than in some other forms of cancer.

Kidney anatomy and function

A little knowledge of kidney anatomy and function can help you better understand your symptoms, as well as understand how cancer in this area can affect your body.

The kidneys are made up of two bean-shaped organs the size of a small fist. Each kidney is located behind the abdominal organs, respectively, on each side of the spine. Some people only have one kidney as a result of a birth defect or disease. They can live normally with only one kidney as long as that kidney is working.

The main functions of the kidneys are to filter impurities, eliminate excess minerals and salt, and eliminate excess water from our blood that is excreted in the urine. Every day, about 180 liters (approximately 45 gallons) of blood are filtered through our kidneys. per day to produce about 1 to 2 liters of urine. The urine then travels through tubes called ureters and is stored in the bladder until it is excreted (urine).

The kidney contains more than one million nephrons, the functional unit of the kidney. Each nephron consists of a glomerulus and a tubule.

Kidney Cancer Types

There are several types of kidney cancer, including:

  • Renal cell carcinoma: Renal cell carcinoma is by far the most common form of kidney cancer, accounting for nine out of 10 kidney cancers.
  • Transitional cell carcinoma : Transitional cell carcinoma accounts for about 7 percent of kidney cancers. They arise from cells of the same type that are involved in bladder cancer , and transitional cell carcinoma is treated more like bladder cancer than renal cell carcinoma.
  • Wilma's tumor : Wilma's tumor is a cancer that usually develops in childhood and is relatively common among childhood cancers.
  • Renal sarcoma: Renal sarcoma is a rare tumor that begins in the connective tissue of the kidney.

This discussion will focus primarily on renal cell carcinoma.

Kidney cancer (renal cell carcinoma) is believed to arise from the tubules of the nephrons.

Kidney Cancer Symptoms

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Unfortunately, kidney cancer symptoms usually do not appear until the disease progresses. When symptoms do occur, some of them may include:


While we are not sure of the exact causes, researchers have identified several risk factors for kidney cancer . Some of these include :

  • Age: The risk of kidney cancer increases with age, and most renal cell carcinomas occur after the age of 40 (Wilma's tumor, by contrast, is more common in children).
  • Gender: Kidney cancer is more common in men than women.
  • Race: Kidney cancer is slightly more common in blacks and American Indians.
  • Smoking: People who smoke have a higher risk of kidney cancer.
  • Occupation: exposure in the workplace to chemicals and substances such as asbestos, benzene, etc.
  • Obesity
  • Family history of kidney cancer or certain genetic syndromes.
  • Certain medications


The diagnosis of kidney cancer can be suspected based on anemia, blood in the urine, physical symptoms, and other abnormal laboratory tests, and this is often done with a combination of imaging tests.

Often times, finding a tumor on an X-ray, such as an X-ray, CT scan, or MRI, while examining another condition, can lead the doctor to suspect kidney cancer.

An ultrasound is often the first test for suspected kidney cancer. Ultrasound uses sound waves to create an image and can distinguish solid tumors from cysts.

CT (computed tomography) is perhaps the most useful test that can be used both to identify and stage kidney cancer. Computed tomography uses a series of x-rays to create a three-dimensional image of the inside of the body.

Magnetic resonance imaging (MRI) may be done in people who cannot receive a CT scan (due to an allergy to CT contrast materials or poor kidney function). MRI uses magnetic images instead of X-rays. MRI is also helpful if the tumor is suspected of having spread to veins near the kidneys.

Sometimes a PET scan or bone scan is done to determine the stage of the kidney tumor.

Unlike many tumors, a biopsy is not always required to diagnose kidney cancer.

If necessary, biopsies can be done in a number of ways and allow pathologists to look for cancer cells under a microscope. Kidney cancer samples are very helpful in prescribing targeted treatments, but they are often obtained during cancer surgery rather than during the diagnostic process.


If cancer is found, additional tests may be needed to find out if kidney cancer has spread to nearby tissues or to other organs. This is called staging .

Kidney cancer is diagnosed by measuring the size of the tumor in the structures of the kidney, including the renal cortex and pyramid, and any signs of spreading to nearby tissues or distant areas of the body.

Stages of kidney cancer

  • Stage 1 tumors are confined to the renal cortex, its outer perimeter.
  • Stage 2 tumors are larger, but still confined to the kidney.
  • Stage 3 tumors spread to nearby blood vessels
  • Stage 4 tumors spread beyond the outer lining of the kidney and can also spread to nearby organs.

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Treatment for kidney cancer depends on the stage of the disease, as well as many other factors, such as your general health, the location of the cancer in your kidney, and more.

Most people with kidney cancer will have surgery. Those with early stage kidney cancer are the best candidates for surgery, but kidney cancer is one of the few solid tumors in which surgery can be beneficial even for advanced metastatic disease (stage 4).

Although surgery is the treatment of choice for most kidney cancers , it can be difficult in the very old or with multiple serious medical conditions. For those who cannot tolerate surgery, there may be treatment options such as cryosurgery (freezing the tumor) or radiofrequency ablation (burning the tumor).

Guide to talking with a kidney cancer doctor

Get our printable guide to your next doctor's appointment to help you ask the right questions.

Several targeted therapies have been approved for use in some people with advanced kidney cancer. These drugs block and prevent the growth and spread of malignant cells. They do this by directly interfering with pathways involved in cancer growth or by preventing the growth of blood vessels needed to supply nutrients to the tumor (they inhibit angiogenesis ).

The side effects of these drugs are different from chemotherapy and are often better tolerated.

Immunotherapy , also known as biological therapy, is a new approach to cancer treatment that works by stimulating the body's own immune system to fight cancer cells. There are several different categories of these drugs that have been shown to be effective in kidney cancer .

Clinical trials are also an option

In addition to the approved treatment options available, many clinical trials are currently underway to find new or better treatments for kidney cancer. Unlike the myths about clinical trials that many have heard of, some of these trials now offer people the opportunity to use therapies that can improve their results.

It may be helpful to note that all of the treatments we use now for cancer were once studied in clinical trials, and now kidney cancer treatments and survival rates are improving.

Radiation is not generally used as a treatment for kidney cancer, but it can be used "palliatively" to relieve discomfort caused by the effects of cancer spread. Chemotherapy has a limited effect against renal cell carcinoma.

Palliative care aimed at treating cancer symptoms and improving quality of life is very important, even for people with early-stage tumors that are likely to be treatable.

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To detect kidney cancer in its early stages, it is important for people to know the possible symptoms of the disease, as well as its risk factors. Once a diagnosis is made, there are many treatment options.

However, prevention is better than cure, and there are many simple things people can do to reduce risk. Stop smoking or do not start smoking, as this is a serious risk factor. Your risk actually decreases when you quit smoking, so it's never too late, and there are many reasons to quit smoking after a cancer diagnosis , even if you've been diagnosed with the disease. Take the time to educate yourself on any chemicals or other substances you find at work and follow the recommended precautions. Finally, eating a healthy diet is important to maintain a healthy weight, as obesity is a risk factor for many cancers, not just kidney cancer.

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