A kidney stone is a small, solid mass that can form in the kidneys and can move into other parts of…
What is kidney cancer?
The kidneys are the pair of organs that remove waste products from blood, regulate blood pressure and the blood's electrolyte balance. Kidney cancer occurs when abnormal cells grow uncontrollably in the kidneys. These abnormal cells can grow to form a cancer, cells of which can separate and spread to other parts of the body (metastasise).
The cause of kidney cancer, as with other cancers, is due to damage to cellular DNA. This damage results in uncontrolled cell growth, which leads to a cancer forming. The cancer can invade nearby tissue, and cells can separate and spread throughout the body via the bloodstream or lymphatic system. In most cases, the exact cause of this cellular damage is unknown.
Risk factors for kidney cancer include:
- Smoking - your risk of developing kidney cancer increases the longer you smoke;
- Age - most cases of kidney cancer occur in people over 45 years of age;
- Gender - kidney cancer is twice as common in men than women;
- Obesity - obesity may cause kidney cancer by causing changes in levels of certain hormones;
- Genetics and family history - genetic conditions, such as tuberous sclerosis and Hippel-Lindau disease, can increase your risk of tumour formation in the kidneys. The tumours are usually benign in tuberous sclerosis and cancerous in Hippel-Lindau disease;
- Radiation - repeated exposure to radiation (for example, in the workplace) may increase your risk;
- High blood pressure (hypertension) - the risk is even greater if, in addition to high blood pressure, you are also overweight, and;
- Dialysis and transplant - if you have received a kidney transplant or are on long-term dialysis for kidney failure, you have an increased risk of developing kidney cancer.
Renal cell carcinoma
In renal cell carcinoma (RCC), which accounts for the vast majority of cases of kidney cancer, the cancer originates in the lining of the small tubes within the kidneys. It is further classified as follows:
- Clear cell RCC - the most common type of RCC. It is so named because when viewed under a microscope, the cells appear clear;
- Papillary RCC - the second-most common type of RCC. Viewed under a microscope, the cancerous cells appear as finger-like projections;
- Chromophobe RCC - the third-most common type of RCC. As with clear cell carcinoma, the cancerous cells appear clear but are much larger;
- Rare types of RCC - collecting duct RCC, multilocular cystic RCC, medullary carcinoma, mucinous tubular and spindle cell carcinoma and neuroblastoma-associated RCC are all extremely rare types of RCC, and;
- Unclassified - in a very small number of cases, RCC is unclassified because it does not fit into any of the above categories.
Transitional cell carcinomas
Transitional cells line parts of the urinary system, such as the bladder and the tubes that urine flows through (ureters and urethra). These cells can stretch to accommodate the storage and flow of urine. In transitional cell carcinomas, which account for a minority of cases of kidney cancer, the cancer originates in the area between the ureter and the kidney (renal pelvis) in these transitional cells.
Nephroblastoma (Wilms tumour)
This rare form of kidney cancer originates in specialised cells, called nephrogenic rest cells, which are present in an unborn baby's kidneys. These cells usually disappear after birth, but not in children who have this type of cancer.
This rare type of kidney cancer originates in the surrounding tissue or blood vessels of the kidneys.
Stages of kidney cancer
Treatment outcomes can vary greatly, depending on the stage of cancer. Cancer is staged according to the size and location of the cancer and whether it has spread to lymph nodes or organs throughout the body.
The cancer is less than 7 cm in diameter and the cancer has not spread outside the kidney.
The cancer is greater than 7 cm in diameter and has not spread outside the kidney.
The cancer can be any size, but has spread to the blood vessels.
The cancer can be any size, but has spread to the lymph nodes.
The cancer can be any size, but has spread throughout the body to other organs.
Signs and symptoms
Most of the time, kidney cancer does not cause any symptoms in the early stages, so if it is detected early, it is often a chance finding. For example, you may be having an ultrasound investigating a liver problem and an unusual mass is seen in one of the kidneys, or a urine dipstick performed during a routine medical examination may find traces of blood. These findings can prompt further investigation into the cause. In later stages, you may actually notice blood in your urine.
Other symptoms include:
Methods for diagnosis
Medical history and physical examination
Your doctor will ask you questions about your symptoms. During the physical examination, your doctor may feel your abdomen for any abnormalities such as an abnormal mass. They may also ask for a urine sample to detect the presence of blood in the urine.
Urinalysis is a routine examination of the urine for cells, microbes or chemicals that indicate a range of different illnesses. This test requires you to urinate in a small plastic cup. Sometimes you will be required to provide a 'first catch' sample, in which you catch the urine immediately as you expel it, while other times you will need to provide a 'midstream' or 'clean catch' sample, which is urine collected after an initial amount has been passed. Midstream samples are used for a urine culture, as they are less likely to be contaminated by the normal bacteria from the skin. Your doctor might order a urinalysis if you have abdominal pain or blood in your urine, but also as a routine test.
Complete blood count
Using a blood sample, a machine can count your number of white blood cells, red blood cells and platelets. A manual count can also be performed by a scientist using a microscope. The complete blood count, also known as a full blood count, is a routine test, but is also used to screen for infection and blood disorders such as anaemia.
Other blood tests
Your doctor might order a range of blood tests that can provide information about kidney and liver function, sugar and proteins in the blood, and electrolyte levels.
Scans used in the diagnosis and management of kidney cancer include:
- Ultrasound - this is often the first scan carried out in the evaluation of the kidneys and ureters, as it provides good information without any radiation;
- Computerised tomography (CT) scan - this type of scan is often used to determine the site and size of the cancer and identify any other areas affected by the spreading of the cancer;
- Magnetic resonance imaging (MRI) - can provide more detailed scans, if needed, to determine the type of treatment, and;
- Positron emission tomography (PET) - this is often used to identify the presence of cancerous cells and assess their spread to other parts of the body.
Fine-needle aspiration (FNA) is used to take a tissue sample (biopsy). It involves your doctor inserting a thin needle into the kidney. This is usually performed using an ultrasound or CT scan to help guide the needle to the suspected cancer.
Types of treatment
There are several surgical options that may be considered by your doctor, including:
- Radical nephrectomy - this is the most common type of surgery for large kidney cancers. It involves the removal of the entire affected kidney. Surrounding tissue such as the adrenal gland, lymph nodes and fatty tissue may also be removed;
- Partial nephrectomy - this surgery involves the removal of the cancer and only some of the kidney. It may be performed when the cancer is less than 4 cm in diameter and easily accessible;
- Surgery for advanced cancer - this includes surgery to remove cancers that have spread beyond the kidney, and;
- Arterial embolisation - this involves cutting off the blood supply to the cancer to starve it of oxygen and the nutrients needed for its growth.
It is possible to survive with only one healthy kidney. Therefore, the removal or embolisation of the affected kidney usually does not impair a person's kidney function.
Other therapies can be used in addition to surgical treatments, to further improve treatment outcomes. They may be given before surgery (neoadjuvant therapy) and/or after surgery (adjuvant therapy). When given before surgery, they aim to reduce the size, and therefore stage, of the cancer. When given after surgery, they aim to help prevent the cancer returning. These non-surgical treatments include chemotherapy, radiotherapy, targeted therapy or a combination of these.
Occasionally, these therapies may be used if individuals are not suitable for surgical treatment. Often in these situations, the aim of treatment is to control symptoms and not necessarily for cure. The treatment options and aims can differ based upon the individual, the stage and type of cancer. Your doctor can help explain this information in more detail.
Chemotherapy works by damaging cancer cells and stopping their reproduction. Various medications can be used, which can be administered intravenously or orally. They are often given in cycles, with intervening rest periods, to help reduce toxic side effects. These side effects include:
- Nausea, vomiting and fatigue;
- Altered bowel habits, such as constipation or diarrhoea;
- Joint and muscle pain;
- Temporary hair loss from the head and body, and;
- Tingling in the hands and feet - some chemotherapeutic agents can affect the nerves. It is important to tell your doctor if you develop these symptoms.
Side effects occur because chemotherapy can also affect healthy cells. Your doctor will monitor your dosage carefully to achieve an optimum therapeutic effect.
External beam radiation uses focused X-rays to destroy cancerous cells. It is not often used for kidney cancer, as cancerous cells in the kidney are not as sensitive to radiation as other types of cancerous cells. However, when surgery is not possible, such as in cases of advanced kidney cancer, radiotherapy and chemotherapy can be the main line of treatment. In this situation, radiotherapy is used to relieve symptoms, such as blood in the urine and pain. Another form of radiation therapy is brachytherapy. This involves implanting radioactive seeds directly into or close to the cancer, which deliver cell-destroying radiation directly into the cancer.
Some medications can be used to help stop the growth of the cancer by blocking the action of enzymes involved in the growth of cancer cells. These medications, such as tyrosine kinase and mTOR inhibitors, can often be taken in tablet form.
Immunotherapy is usually only used in advanced stages of kidney cancer. It involves the use of medications that boost the immune system to work harder or smarter to attack cancer cells.
Some people diagnosed with cancer seek out complementary and alternative therapies. None of these therapies are proven to cure cancer, but some can help people feel better when used together with conventional medical treatment. It is important to discuss any other treatments with your doctor, before starting them.
Treatment side effects
Treatment for kidney cancer can cause several side effects, including:
- Nausea, vomiting and fatigue from chemotherapy and radiotherapy;
- Altered bowel habits - constipation or diarrhoea;
- Joint and muscle pain may occur after a treatment session and can last a few days;
- Temporary hair loss - some types of chemotherapy result in hair loss on the head and body. It may grow back after treatment has ended;
- Tingling in the hands and feet - some chemotherapeutic agents can affect the nerves. It is important to tell your doctor if you develop these symptoms, and;
- Lymphoedema - the lymphatic system drains excess body fluid. Surgical removal of the lymph nodes can result in a build-up of fluid leading to swelling, such as in the legs. Massage and compression clothing can help relieve swelling.
Advanced kidney cancer
Advanced kidney cancer can metastasise. This is when the cancer spreads to other parts of the body through the bloodstream or lymphatic system, causing a harmful effect on the function of the affected organs.
The prognosis for kidney cancer depends on the type and stage of the disease, but the overall five-year survival rate is 72%. For those who survive the first year, this increases to 84% and for those who survive the first five years, the forward five-year survival rate further increases to 90%. 
It is important to remember survival rates are only an indication, and are based upon the averages of previously treated patients. It is not an absolute prognosis for an individual. It is often difficult to accurately predict an individual's cure or survival rate. Constant advances in treatment are continually improving these statistics.
The exact cause of kidney cancer is unknown in many cases, so it usually cannot be prevented, but you can reduce your risk by quitting smoking and following a healthy diet to achieve and maintain a healthy weight.