Kidney cancer

What is it?

The kidneys are two fist-sized organs that produce urine and thus filter out toxic by-products and excess fluids from the blood. The kidneys also keep the ions (salt, potassium...) and acidity of the blood in balance.

A kidney tumour is an abnormal growth or proliferation of kidney cells.

Kidney cancer is slightly more common in men than in women and is usually diagnosed in the 50-70 age group. The most common form of kidney cancer is renal cell carcinoma. There are different subtypes of renal cell carcinoma: clear cell, chromophobe, papillary renal cell carcinoma.

Which factors influence kidney cancer?

The cause of kidney cancer is not clear, but research has shown that certain factors can increase the risk of developing kidney cancer:

• smoking, obesity and high blood pressure
• kidney cancer within the same family
• excessive intake of certain painkillers (acetaminophen and anti-inflammatory drugs)
• exposure to asbestos and blast furnaces
  

Symptoms

Kidney cancer often produces no symptoms at an early stage.

Symptoms that may be indicate kidney cancer:

• blood in the urine
• a hard lump in the abdomen
• unexplained weight loss or loss of appetite
• pain in the side or in the lower back

If the cancer spreads outside the kidney, other symptoms may occur, depending on the organ to which the cancer has spread. For example, shortness of breath or coughing up blood can occur when the cancer has spread to the lungs. Bone pain or fractures can occur when the cancer has spread to the bone. Neurological symptoms may occur when the cancer has spread to the brain.

More frequently, however, there are additional, general symptoms, so-called ‘paraneoplastic symptoms’ such as anaemia, fever, high blood pressure, ion abnormalities in the blood or abnormal liver values. These general symptoms therefore also occur regularly when kidney cancer has not metastasised.

Diagnosis

• Ultrasound imaging and/or a CT scan: to visualise the tumour; or to research suspected metastases (e.g. in the lungs).
• MRI: also to visualise the tumour; or to investigate suspected metastases (e.g. in the bones).
• Biopsy: a small piece of tissue is removed from the tumour and examined to see whether the tumour is benign or malignant.
• PET scan: provides information on the extent to which the cancer has metastasised
• Bone scan: to check whether the cancer has spread to the bones

Treatment

The gold standard treatment for local kidney cancer (i.e. without metastases) is surgical removal of the affected kidney or surgical removal of just the kidney tumour. For many types of kidney tumours where metastases are already present, surgical removal of the affected kidney remains recommended. Depending on the size, the exact site of infection and the degree of metastasis of the kidney tumour, kidney surgery is performed in different ways. Sometimes ‘open’ surgery is necessary, which means that the doctor has to make a larger incision in the abdomen. Another method is conventional laparoscopy: this involves removing the kidney with long, fine instruments via small incisions (keyhole surgery). Sometimes it is preferable to connect these fine instruments to a robotic system: da Vinci® Surgery. This is referred to as a robot-assisted operation.

Kidney cancer is quite resistant to radiation, so radiotherapy is not often used in the treatment of kidney cancer.

Kidney cancer can be cured if detected and treated early. Often, ‘just’ a surgical intervention is enough, without additional treatments. Patients in whom kidney cancer is found at an early stage have a very positive prognosis.

Latest publication date: 23/01/2024
Supervising author: Dr Ameye Filip