Kidney cancer is a malignant cell growth (a tumour) in the kidneys. Its medical name is renal cell carcinoma. A tumour in the kidney can also be benign (non-cancerous).
Kidney cancer is a general term. There are many variations of tumours in the kidney and stages of the disease. Your treatment and experience depend on the specific characteristics of the tumour and the expertise of your medical team.
Kidney cancer represents around 2% of all cancer diagnoses worldwide. In the last twenty years, the number of cases of kidney cancer worldwide has increased slightly, but the survival rate has also gone up in most of the region. Because of the more frequent use and improvements in ultrasound and CT imaging technology, more kidney cancers are now diagnosed at an earlier stage.
Men are more likely to be diagnosed with kidney cancer than women. Most people are diagnosed between the ages of 60 and 70.
Stages of kidney cancer
There are different stages of kidney cancer. If the tumour is limited to the kidney and has not spread, this is called localised kidney cancer. In locally advanced kidney cancer, the tumour has grown out of the kidney into surrounding tissue and invaded veins, the adrenal gland, or lymph nodes. Doctors speak of metastatic disease if the cancer has spread either to distant lymph nodes or other organs.
Risk factors for kidney cancer
The causes of kidney cancer are often difficult to determine. General risk factors are smoking and obesity.
Having a first-degree relative with kidney cancer or high blood pressure are also potential risk factors. Certain lifestyle changes, most importantly quitting smoking and keeping a healthy weight, may reduce the risk of developing kidney cancer.
In most cases kidney cancer is asymptomatic, which means that there are no clear symptoms to indicate it. Most kidney tumours are found during a routine ultrasound or a similar imaging procedure for other conditions such as back pain.
About 1 in 10 people do experience symptoms like pain in the side of the body, abdominal mass or blood in the urine. This could be a sign that the disease has advanced. Some people can also experience so-called paraneoplastic syndromes. These are reactions the body can have to any type of cancer and may include high blood pressure, weight loss, fever, anaemia, muscle mass loss, and loss of appetite. Syndromes more commonly associated with kidney cancer include changes in liver enzymes and blood platelets. These changes are usually discovered during tests and normally do not cause any symptoms.
Bone pain or a persistent cough could be signs that the cancer has spread through the body. This is known as metastatic disease.
Because there are several types of kidney tumours, the doctor does a series of tests to better understand your specific situation. These tests include a medical history, laboratory tests and scans. Sometimes a family history is also taken. A CT scan or MRI scan will reveal the size of the tumour and if it has invaded local veins, lymph nodes, or surrounding organs. This is important to determine further treatment. The doctor may also perform a physical examination and take blood and urine for testing.
With the results of your scan, the urologist can define the stage of the disease. By analysing tumour tissue, received either during surgery or biopsy, the pathologist determines the subtype of the tumour and whether or not it is an aggressive form. Together, the stage, subtype, and aggressiveness of the tumour form the classification.
Classification of the kidney tumour is used to estimate your individual prognosis. Based on this individual prognosis your doctor will discuss the best treatment pathway for you.
In some cases you may need additional tests to check your kidney function. This is important if you only have one kidney or if you are at risk of kidney failure because you have diabetes, high blood pressure, chronic infections, or a kidney disease.
Imaging is important for the diagnosis and classification of kidney tumours. Most common imaging techniques are ultrasound, CT scans, and MRI. In some cases a biopsy is done to get more insight into the specific characteristics of the tumour.
After a tumour is detected, the doctor first needs to know whether it is malignant. A contrast-enhanced ultrasound, CT, or MRI scan of the abdomen and pelvis provides information about this. CT and MRI scans also show:
- The location and size of the tumour
- Whether or not you have enlarged lymph nodes
- Whether or not the tumour has spread to neighbouring organs, such as the adrenal gland, liver, spleen or pancreas
- Whether the urinary tract is affected by the tumour
For a contrast-enhanced scan, a contrast medium is administered through an IV, usually in your arm. The contrast medium highlights your veins and arteries by giving them a different colour in the pictures taken during the scan. This type of scan allows the radiologist to analyse the tumour. The results will guide the treatment you receive.
If you are allergic to contrast medium, you will receive an MRI or CT scan without contrast-enhancement.
If your doctor thinks the cancer may have spread to the lungs, you will get further tests, like a CT scan. You may need a bone or brain scan if you have symptoms such as bone pain or epileptic seizures. These scans are done to see whether the cancer has spread to bones or the brain.
Renal tumour biopsy
During a renal tumour biopsy, one or more samples of tumour tissue are taken. First, you receive local anaesthesia. Then the doctor inserts a needle through your skin and uses ultrasound or CT imaging to locate the tumour. The tissue samples are analysed by the pathologist in order to help determine future treatment.
Renal biopsy is not standard procedure in the diagnosis of kidney cancer. You may need a biopsy in case:
- The results of your scan are not clear enough
- You have a small tumour which could be treated with active surveillance
- You have a small tumour which could be treated with radiofrequency ablation or cryotherapy
Biopsies may cause blood in the urine. In rare cases, they can cause more severe bleeding. A renal tumour biopsy is generally a harmless procedure.
Kidney tumours are classified according to their stage, subtype, and the grade of aggressiveness of the tumour cells. These three elements are the basis for your possible treatment pathway.
Tumour stage indicates how advanced the tumour is and whether or not there are metastases in the lymph nodes or other organs.
Kidney tumour stage is based on the Tumour Node Metastasis (TNM) classification. The urologist looks at the size and invasiveness of the tumour (T) and determines how advanced it is, based on 4 stages. Whether any lymph nodes are affected (N) or if the cancer has spread to any other parts of your body (M) is also checked. If kidney tumours metastasise they generally spread to the lungs, or to the bones or brain. Figures 1 to 5 illustrate the different stages.
Next to staging, the subtype of kidney tumours is important. The subtype is determined by a pathologist and the procedure is known as histopathological analysis. The specialist examines the tumour tissue either taken during a biopsy or after it has been removed during surgery. Renal biopsy is not a standard procedure in the diagnosis of kidney cancer. In most cases, the subtype of your tumour will not be known until after you have surgery.
There are various subtypes of kidney tumours. Most kidney tumours are renal cell carcinomas. Of these, the most common subtype is clear cell renal cell carcinoma
If you are diagnosed with a rare kidney tumour your doctor will give you detailed information about different treatment possibilities. These may differ from therapy for the more common kidney cancer subtypes. Treatment options are discussed by a multidisciplinary team of doctors, to find the best approach for you (See: The medical team).
Some tumours in the kidney are non-cancerous. These are known as benign kidney tumours. The most common benign tumours of the kidney are oncocytomas and angiomyolipomas.
Oncocytomas are generally diagnosed after histopathological analysis, because scans cannot always identify them clearly. The most common treatment options for these tumours are partial nephrectomy and active surveillance. Read more about these treatment options in the section Localised Kidney Cancer.
An angiomyolipomas (AML) is a benign tumour and more likely to occur in women. It is generally diagnosed after ultrasound, CT or MRI scans, or if the tumour bleeds and causes symptoms. Although AML is a benign tumour, the risk of spontaneous bleeding in the kidney increases if it continues to grow. Surgery to remove the tumour is recommended if:
- You have a large AML (a tumour larger than 4 cm)
- You are a woman under the age of 45
- The tumour causes symptoms
- It is difficult for you to visit your doctor in case of emergency, because you live far away from a hospital or you have limited mobility.
Generally, an AML is removed with partial nephrectomy but in some cases it may be necessary to remove the whole kidney. Radical nephrectomy is recommended in case of severe bleeding of the tumour.
Some masses in the kidney are not tumours but renal cysts. These are sacs filled with fluid located on the kidney and are easily recognised on a CT scan. Cysts can be malignant. If this is the case they need to be removed by surgery.
The third component of the classification is an evaluation of how aggressive the tumour cells are. The Fuhrman nuclear grade is the most commonly used system to determine this. The pathologist classifies your tumour in 1 of 4 grades.
After diagnosis and classification, your doctor will discuss different treatment and follow-up options with you. The recommended treatment pathway is based on the TNM staging, the Fuhrman grade, and the subtype of the tumour. Your individual prognosis can also be estimated after classification. However, keep in mind that this is a prediction which does not take into account any unexpected developments.
If you are diagnosed with localised kidney cancer, your doctor can recommend treating the cancer with partial nephrectomy, radical nephrectomy, active surveillance, radiofrequency ablation, or cryotherapy. Each procedure has its own advantages and disadvantages. The choice of treatment depends on your individual situation.
If you are diagnosed with locally-advanced kidney cancer, your doctor can recommend to treat the cancer with radical nephrectomy or embolisation. Each procedure has its own advantages and disadvantages. The choice of treatment depends on your individual situation.
Kidney tumours can spread to other organs or distant lymph nodes. This is called metastatic disease. In metastatic disease, the kidney tumour is referred to as the primary tumour and the tumours in other organs are called metastases. Your doctor may recommend to treat metastatic disease with surgery, usually in combination with antiangiogenic therapy, also known as targeted therapy. In rare cases, immunotherapy is also used. For the treatment of metastases, radiotherapy may be recommended.
Generally, metastatic disease cannot be cured. The treatment of metastatic disease aims to reduce the size of the primary tumour and the metastases. This will give you the chance to live longer and have fewer symptoms.
Sometimes recovery from kidney cancer is not possible. When treatment is no longer successful you may be offered palliative care to make you more comfortable. Palliative care is a concept of care with the goal to optimise your quality of life if you cannot recover from your illness.