What Is Kidney Cancer? What Causes Kidney Cancer?

Editor's Choice
Main Category: Urology / Nephrology
Also Included In: Cancer / Oncology
Article Date: 21 Sep 2009 - 14:00 PDT

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Kidney cancer, or cancer of the kidney, is any type of cancer that has arisen from the kidney. Kidney cancer does not usually include a cancer that arose outside the kidney and metastasized to include metastatic cancer of the kidney.

The most common types of kidney cancer include renal cell carcinoma and urothelial cell carcinoma of the renal pelvis. Renal cell carcinoma accounts for approximately 90% of all kidney cancers. Urothelial cell carcinoma is a type of cancer that occurs in the urinary system, specifically the kidney, urinary bladder, ureter, urethra and urachus.

The following are also types of kidney cancers:

• Squamous cell carcinoma
• Juxtaglomerular cell tumor (reninoma)
• Angiomyolipoma
• Renal oncocytoma
• Bellini duct carcinoma
• Clear-cell sarcoma of the kidney
• Mesoblastic nephroma
• Wilms' tumor (usually diagnosed in children under 5)
• Mixed epithelial stromal tumor

On very rare occasions these cancers and potentially cancerous tumors that usually originate in other parts of the body, can start off in the kidneys: clear cell adenocarcinoma, transitional cell carcinoma, inverted papilloma, renal lymphoma, teratoma, carcinosarcoma, carcinoid tumor of the renal pelvis.

Kidney cancers originate mainly in two parts of the kidney - the renal tubule and the renal pelvis. Most that originate in the renal tubule are renal cell carcinoma and clear cell adenocarcinoma. Most cancers that originate in the renal pelvis are transitional cell carcinoma.

3% of all adult cancers in the Western Europe are kidney cancers. There were 5,745 diagnosed cases of kidney cancer in England and Wales in 2004. In the USA there are over 50,000 newly diagnosed cases of kidney cancer each year, causing over 13,000 deaths annually. Worldwide, approximately 208,000 cases of kidney cancer are diagnosed annually, accounting for nearly 2% of all cancers. Regions in Asia and Africa have the lowest rates of kidney cancer worldwide, while North America has the highest rate.

In the UK kidney cancer is the eighth most common form of cancer in adult men and the fourteenth most common in adult women.

Adults aged between 50 and 80 years are more likely to develop kidney cancer compared to other people. This type of cancer affects men more than women.

The incidence of kidney cancer in the developed world has been steadily increasing over the last three decades. Some experts believe there is a close link between this increase and a parallel rise in rates of adult obesity.

Most of the rest of this article is about renal cell carcinoma.

What are the risk factors for kidney cancer?

A risk factor is something that increases the risk of developing a disease or condition. For example, regular daily smoking increases the risk of developing lung cancer; therefore smoking is a risk factor for lung cancer.

• Risk factors for renal cell carcinoma (90% of all kidney cancers)
  
  
  • Age - the older you are the higher the risk. There is a significant increase in risk for people aged 60 or more.
  
  
  • Sex - the ratio between men and women is 1.5 to 1. In other words, for every woman diagnosed 1.5 men are diagnosed with renal cell carcinoma.
  
  
  • Obesity* - an obese person has a significantly higher risk of developing the disease compared to a person of normal weight for his/her height and age.
  
  
  • Smoking* - regular tobacco smokers have a much higher risk. This risk starts to drop as soon as the person quits.
  
  
  • Hypertension* (high blood pressure) - nobody is sure why there is an increased risk. Some say it is the hypertension itself, while others blame anti-hypertensive medications.
  
  * Experts estimate that smoking, obesity and hypertension account for approximately 50% of all renal cell carcinomas.
  
  
  • Chemicals at work - workers who are exposed to specific chemicals, such as asbestos, trichloroethylene and cadmium are more likely to develop renal cell carcinoma than other people. Asbestos, a mineral, was widely used in construction. Cadmium, a metal, is used in the manufacture of batteries. Trichloroethylene, an industrial solvent, is used to strip paint from metals.
  
  
  • Kidney failure treatment - patients on long-term dialysis for chronic kidney failure treatment are more likely to develop renal cell carcinoma.
  
  
  • Kidney transplant recipients - patients who have received a kidney transplant and have to take immunosuppressant medications have a higher risk of developing renal cell carcinoma.
  
  
  • Von Hippel-Lindau disease - a genetic disease which raises the patient's risk of developing several kinds of tumors, including renal cell carcinoma.
  
  
  • Hereditary papillary renal cell carcinoma - characterized by the development of multiple papillary tumors in both kidneys (a papillary tumor is shaped like a small mushroom with its stem attached to the inner lining of an organ).


• Risk factors for transitional cell carcinoma
  
  
  • Smoking
  • Workplace chemicals
  • Phenacetin - an OTC (over-the-counter) pain relieving medication which was taken off the market during the 1980s. The Medicines and Healthcare products Regulatory Agency (MHRA) withdrew phenacetin from the UK market in 1980. The Food and Drug Administration (FDA) in the USA withdrew phenacetin in November 1983.

What are the symptoms of kidney cancer?

Early stages of kidney cancer do not usually show any symptoms.

• During the advanced stages, the following signs and symptoms may appear:
  
  
  • Blood in the urine
  • A continuous pain below the ribs
  • A lump in the abdomen


• If the cancer metastasized the following symptoms may also emerge:
  
  
  • Constant fever
  • Tiredness (fatigue)
  • Weight loss
  • Bone pain
  • Night sweats

What are the causes of kidney cancer?

Cancer starts when the structure of the DNA (deoxyribonucleic acid) alters - a genetic mutation. DNA provides the cells with a basic set of instructions, much like a computer program for life. The instructions tell cells when to grow, reproduce, and die, among other things. When there is a genetic mutation cells grow in an uncontrollable manner, eventually producing a lump (tumor).

If the cancer is left untreated it grows and eventually spreads to other parts of the body, usually through the lymphatic system - a series of nodes (glands) that exist throughout the body. The lymph glands produce many of the cells of our immune system. As soon as the cancer reaches the lymphatic system it can spread anywhere in the body and invade bones, blood and organs. The cancer cells continue reproducing uncontrollably, gradually occupying more and more space.

Our kidneys are part of our urinary system which gets rid of waste and excess fluid and electrolytes from the blood. The kidneys also control the production of red blood cells and regulate your blood pressure.

There are over 1 million nephrons in each kidney. Nephrons are the tiny filtering units in the kidneys - they filter out waste products as well as minerals and water the body needs expel. The liquid waste is called urine. Urine flows through the ureters; two narrow tubes that connect the kidneys to the bladder. Urine is stored in the bladder. When we urinate (pee) urine travels down another tube, called the urethra, and out of the body.

• Renal cell carcinoma - this type of cancer typically starts in the cells that line the tiny tubes in each nephron. Generally, renal cell tumors grow as one, single mass. However, it is possible for more than one tumor to grow in one kidney, and sometimes in both kidneys.


• Transitional cell carcinoma - cancer develops in the tissue that forms the tubes that connect the kidneys to the bladder. This type of cancer can begin in the ureters and also in the bladder itself.


• Wilms' tumor - a childhood kidney cancer caused by the loss or inactivation of a tumor suppressor gene called QT1 on chromosome 11. Tumor suppressor genes generally suppress tumor growth and control cell growth.

How is kidney cancer diagnosed?

• Blood and urine tests - these will be done to rule out any other possible causes of symptoms, such as kidney stones or an infection.


• Ultrasound scan - sound waves are used to create an image of the target area. This scan can help the doctor identify any change in the shape of the kidney which could be caused by a tumor.


• A CT (computerized tomography (CT) scan - this is a medical imaging method that employs tomography. Tomography is the process of generating a two-dimensional image of a slice or section through a 3-dimensional object (a tomogram). Put simply, many pictures are taken and then put together as a 3-D image. Most patients will be given a dye to drink which shows up on the scan.


• A biopsy - if the doctor suspects the patient has kidney cancer an image-guided biopsy will be performed. A needle is guided through the skin into the kidney - the guidance system is either ultrasound or CT. A small sample of kidney tissue is removed and examined under a microscope to check for the presence of cancer cells.
  
  A biopsy procedure increases the risk of infection and bleeding. There is also a rare chance that a biopsy could help the cancer spread to the area where the needle is inserted. Some doctors may not do a biopsy if they are fairly sure cancer is present, and proceed straight to surgery, thus avoiding the additional risks of a biopsy. Kidney biopsies are more commonly done on patients who are not thought to have cancer, or those who cannot be operated on.

Transitional cell cancer - additional tests


• Excretory urogram - this is an X-ray of the patient's urinary system which may show signs of cancer. A dye is injected into a vein in the patient's arm. This dye is processed by the kidneys and urinary system and shows up on the X-ray.


• Cystoscopy - the doctor uses a cystoscope, a long narrow tube with a special lens and light at the end, to see inside the patient's bladder. The device is inserted via the urethra. If necessary the doctor can also take a biopsy (small tissue sample) during this procedure.

Kidney cancer stages

• American Joint Committee on Cancer TNM staging system
  
  
  T - this indicates the size of the primary (main) tumor and whether or not it has spread into nearby areas.
  
  N - this indicates the extent of the spread to regional (nearby) lymph nodes.
  
  M - this indicates whether the cancer has metastasized to other organs elsewhere in the body, e.g. the lungs, bones, liver, and distant lymph nodes.
  
  
  The letters T, N, and M are followed by numbers; these numbers, from 0 to 4 give more details regarding severity. If the T, N or M is followed by the letter X it means it "cannot be assessed because the information is not available". Below are the letters with their numbers or X and what they mean:
  
  
  TX - the main (primary) tumor cannot be assessed as no information is available.
  T0 - there is no evidence of a primary tumor.
  T1a - the tumor is approximately 1.5 inches (4cm) across. It is limited to the kidney.
  T1b - the tumor is greater than 1.5 inches (4cm) across, but not greater than 2.75 inches (7cm) across. It is limited to the kidney.
  T2 - the tumor is greater than 2.75 inches (7cm) across. It is limited to the kidney.
  T3a - the tumor has spread into the adrenal gland, or into fatty tissue that surrounds the kidney. It has not spread beyond the Gerota's fascia (a fibrous envelope of tissue that surrounds the kidney) and nearby fatty tissue.
  T3b - the tumor has spread into the renal vein and part of the vena cava in the abdomen.
  T3c - the tumor has spread to the vena cava within the chest, or has invaded the wall of the vena cava.
  T4 - the tumor has spread further than the Gerota's fascia.
  
  NX - nearby lymph nodes cannot be assessed as no information is available.
  N0 - there is no spread to nearby lymph nodes.
  N1 - the tumor has spread to one nearby lymph node.
  N2 - the tumor has spread to at least 2 nearby lymph nodes.
  
  MX - extent or presence of metastasis cannot be assessed as no information is available.
  M0 - the cancer has not spread to distant lymph nodes or other organs.
  M1 - the cancer has metastasized; it has spread to distant lymph nodes or/and other organs, such as the brain, lungs or bones.
  


• Four stage system for kidney cancer
  Stages 1, 2, 3 or 4 are combined with the T, N, and M categories:
  
  
  Stage 1 (T1a-T1b, N0, M0) - the tumor is under 2.8 inches (7cm) in diameter and is limited to the kidney.
  
  Stage 2 (T2, N0, M0) - the tumor is greater than 2.8 inches (7cm) in diameter, and is still limited to the kidney.
  
  Stage 3 - the cancer has spread outside the kidney and may possibly have reached the adrenal gland, nearby blood vessels, a lymph node, or the fat that surrounds the kidney.
  
  
  • Stage 3 (T3a-T3c, N0, M0) - the primary tumor has reached the adrenal gland, fatty tissue surrounding the kidney, the renal vein, or/and the vena cava. Tumor has not spread further than Gerota's fascia. Cancer has not spread to lymph nodes or distant organs.
  
  
  • Stage 3 (T1a-T3c, N1, M0) - the primary tumor has not spread further than Gerota's fascia but can be of any size and may be outside the kidney. The cancer has spread to 1 nearby lymph node, but not to distant lymph nodes or other organs.
  
  Stage 4 - the cancer has spread to at least one lymph node, or has spread to other organs.
  
  
  • Stage 4 (T4, N0-N1, M0) - the primary tumor has spread further than the Gerota's fascia and has spread to only one nearby lymph node. Cancer has not spread to distant lymph nodes or other organs.
  
  
  • Stage 4 (any type of T, N2, M0) - the principal tumor is of any size and may be outside the kidney. The cancer has spread to 2 or more nearby lymph nodes, but has not spread to distant lymph nodes or other organs.
  
  
  • Stage 4 (any type of T, Any type of N, M1) - the principal tumor may be of any size and can be outside the kidney. It may have spread to nearby lymph nodes, or it may have not. It has spread to distant lymph nodes; it may have spread to other organs.

What are the treatment options for kidney cancer?

Treatment options depend on several factors, including the patient's general health, the type of kidney cancer, and whether it has spread - plus the patient's own preferences.

Surgery - most kidney cancers have surgery as the initial treatment:


• Nephrectomy (removing a kidney) - a radical nephrectomy means removing the kidney and the adrenal gland that is just above it, a border of healthy tissue and the adjacent lymph nodes. The adjacent lymph nodes will be checked in order to make sure the cancer has not spread beyond the kidney. The surgery can be done laparoscopically - small incisions are made in the abdomen into which a video camera and surgical tools go in. The surgeon watches a video monitor. A robotic nephrectomy is also possible.
  
  If the tumor is less than 1.5 inches (4cm) in diameter the surgeon may only have to remove part of the kidney (partial nephrectomy).
  
  It is possible to live a normal life with just one kidney - the other kidney will make up for the loss.
  
  Some patients, especially those who are unwell or frail, may not be able to undergo surgery.
  
  Even if the cancer has spread outside the kidney the patient may still benefit from having the kidney removed. Removing the kidney may ease pain, and make other types of non-surgical treatments more effective.


• Nephron-sparing surgery - the tumor is surgically removed, but not the kidney. This may be an option during the early stage of kidney cancer, or if the patient has only one kidney.

When surgery is not possible - for patients who cannot undergo surgery because the risks are too high, the following treatment options are possible (some of these treatments may also form part of a treatment program that includes surgery):


• Embolization - the aim here is to block the flow of blood to the tumor. The surgeon inserts a catheter, a small tube, into the groin. X-ray images guide the catheter into the blood supply for the kidney. A special material passes through the catheter into the blood vessel that blocks the blood supply to the kidney, and thus starving the tumor of oxygen and nutrients, causing it to shrink.


• Cryoablation - one or more cryoprobes (special needles) are inserted through small incisions into the tumor. A gas in the needles freezes the cells around the tip of each needle. The needles are guided with a CT scan. The doctor freezes the cancer cells. Another gas warms the tissue up again (thawing them), and then the cells are refrozen. This freeze-thaw cycle kills the cancer cells. Patients may experience some pain after the procedure, and on very rare occasions some bleeding, infection and damage to tissue close to the tumor.

Advanced or recurrent kidney cancer treatment - treatments for kidney cancer that comes back, or kidney cancer that has spread out of the kidney include:


• Surgery - the aim here is to surgically remove as much of the tumor as possible.


• Biological therapy (immunotherapy) - this involves drugs that use the body's own immune system to fight cancer. Examples are interferon and interleukin-2 (aldesleukin) - both synthetic versions of chemicals our bodies make. Side effects include nausea, vomiting, chills, elevated body temperature and loss of appetite.


• Targeted therapy - these are medicines which are designed to target and interrupt (destroy) the functions that cancer needs in order to thrive, such as the blood supply. They include:
  
  
  Sunitinib (Sutent)
  Sorafenib (Nexavar)
  Bevacizumab
  Temsirolimus
  


• Clinical trials - these are studies of new treatments and therapies for kidney cancer and other diseases. Being a clinical trial participant gives the patient the opportunity to take part in latest treatments. However, as they are trials it is important for the patient and doctor to weigh the potential benefits and risks carefully.

Radiotherapy - although radiotherapy cannot usually cure kidney cancer, it may help reduce its spread, as well as helping reduce pain. Patients undergoing radiation therapy (radiotherapy) typically have a few minutes treatment daily for a number of days. When radiotherapy is used to control rather than to cure a cancer the side effects tend to be less severe.

Radiotherapy for kidney cancer may have the following side effects:


Fatigue
Nausea
Vomiting

Coping with knowing you have kidney cancer

One of the most common problems for people who are diagnosed with cancer is coming to terms with having an incurable or potentially incurable disease. The patient may experience grieving-like feelings, and also go through the classic stages of denial, anger, bargaining, depression, and finally acceptance. The bargaining stage is when the patient tries to bargain with the doctor - asking about any type of treatment that may prolong his/her life.

Talking to a well-qualified counselor has been shown to help patients with feelings of anxiety and depression.

We all cope with a cancer diagnosis in our own way. In my case (prostate cancer 2008) the shock and fear came after my operation when tests indicated I was in the clear. Others may experience shock and fear immediately after the initial diagnoses and find that those feelings gradually subside. Whichever way it affects you, it is important to remember that stoicism can be both an asset and a problem. Stoicism can help your carry on with life and get through things; but it can also stop you from accepting help and benefitting from the comfort, encouragement and support of others.

• Inform yourself - ask your doctor and members of the medical team details about your diagnosis - ask them what type of cancer you have, what stage it is, and what options are available and how effective they are. Read all about various treatment options. Ignorance and fear often go together. It is better to understand what you have, regardless of how mild or severe it is, than to walk around bouncing from hope to despair and not knowing what is going on.


• Look after yourself - make sure you eat plenty of fruits and vegetables, sleep at least 7.5 hours each day, get plenty of exercise (ask your doctor whether you can). Your body will respond better to treatment if you are as healthy as you can be.


• Welcome help - your family members and friends will want to help. Most of them will welcome an opportunity to do something - so let them. Not only will you feel you are not alone, you will most probably have more time and energy to focus on getting the most out of your treatment. Talking to family members and close friends will help your mental, emotional, spiritual, and ultimately physical health.


• Spiritual health - if you belong to a religion and have faith you may find that prayer takes on a new and powerful meaning. If you are not religious, consider joining a meditation group.

Prevention

The following measures may help reduce your risk of developing kidney cancer, as well as other cancers, diseases and conditions:

• Don't smoke
• Eat plenty of fruit and vegetables
• Exercise regularly
• Keep your body weight within normal limits for your height, sex and age
• Get at least 7 hours good quality continuous sleep every night (or 24-hour period)
• Maintain healthy blood pressure
• Avoid toxic chemicals

Written by: Christian Nordqvist


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