Kidney cancer

The tumor is usually discovered during a routine examination that takes place for another reason. Clinical symptoms are usually only found in advanced stages of the disease. In the localized stage, the tumour is usually removed surgically; in advanced stages, systemic therapy is necessary.

Kidney tumor: development, epidemiology, risk factors

In principle, a distinction is made between benign and malignant masses in the kidney. The malignant kidney tumor is described in more detail below. The term renal cell carcinoma is also used as a synonym.

A distinction is made between the most common form, clear cell renal cell carcinoma, and so-called non-clear cell carcinomas (papillary, chromophobe), which occur much less frequently overall.

Why a malignant tumor develops in the kidney is still largely unknown. However, there are some risk factors that favor its occurrence. These include, for example, smoking, high alcohol consumption or diseases such as obesity, chronic high blood pressure and chronic kidney disease. But medication or harmful substances can also increase the risk.

Renal cell carcinomas are often discovered by chance during a routine examination, such as an abdominal ultrasound, as they do not usually cause any characteristic symptoms in the early stages. An important alarm sign and usually a sign of an advanced stage is the appearance of blood in the urine. General complaints such as tiredness, loss of appetite and unwanted weight loss as well as pain in the flank area are also possible.

Treatment always depends on the stage of the tumor. In the localized stage, surgery is the method of choice. As a rule, a so-called kidney-preserving procedure is performed. In advanced and metastatic tumor stages, systemic therapy is necessary.

Kidney tumor: frequency and age

Kidney cancer is a rare cancer compared to other types of cancer such as breast, prostate, bowel or lung cancer. In Switzerland, around 990 people contract the disease every year. This type of tumor accounts for around two percent of all cancers.

There are differences between the sexes: around two thirds of patients are men and only around one third are women. Kidney tumors often occur at an older age. More than half are aged 70 or over at the time of diagnosis.

Kidney tumor: risk factors

The most important risk factors for a malignant kidney tumor are

• older age
• Smoking and passive smoking
• High, regular consumption of alcohol
• High-fat, low-fiber diet
• Overweight and obesity(adiposity)
• Chronic high blood pressure(hypertension)
• Chronic kidney disease, such as renal insufficiency, kidney inflammation or cystic kidneys
• Pollutants from the environment and industry such as asbestos, cadmium, lead or aromatic hydrocarbons
• Repeated and long-term exposure to X-rays
• familial predisposition (genes), e.g. Von Hippel-Lindau syndrome – those affected then develop kidney cancer at a young age.

Kidney tumor: symptoms

As described above, kidney tumors in the early stages usually cause no or only non-specific symptoms. In most patients, symptoms often appear late and the disease is already at an advanced stage with metastases (metastasis of tumor cells to other organs).

The following symptoms may indicate a tumor disease:

• Tiredness, fatigue, exhaustion
• Decrease in physical performance
• Fever, night sweats
• Loss of appetite
• unwanted weight loss
• General feeling of discomfort
• Blood in the urine (hematuria)
• Pain in the kidney area (the flanks) that radiates to the back
• Anaemia (anemia)
• High or low blood pressure

No special measures are planned for the early detection of kidney cancer in the doctor’s surgery. In contrast to skin or breast cancer, there are no screening measures aimed at healthy people without symptoms. The general advice is therefore to visit us as soon as possible if you have symptoms such as blood in your urine or flank pain.

Kidney tumor: diagnosis at the USZ

The first step is always to take a detailed medical history (patient interview). The following questions are important here:

• What exactly are your symptoms?
• When did they first appear?
• How intense are the complaints?
• How long have the symptoms been present?
• Where are they located?
• Do you have any known diseases?
• Are there any diseases in your family? Which?
• Do you take medication regularly? If yes: Which and since when?
• Do you smoke? If yes: Since when and how much?
• Do you drink alcohol regularly?
• Are you often exposed to harmful substances at work or in everyday life?

This is followed by a physical examination, which includes palpation of the abdomen, kidney region and lymph nodes. A large tumor in the kidney can sometimes be felt from the outside in very slim patients. Additional blood (e.g. creatinine) and urine tests (e.g. blood in the urine) can provide additional indications of cancer of the kidney.

Imaging procedures are then used, for example:

• Ultrasound examination (sonography)
• Computed tomography (CT)
• Magnetic resonance imaging (MRI = magnetic resonance imaging)
• Positron emission tomography (PET/CT or PET/MR)
• Scintigraphy (bone metastases)

These methods indicate whether a disease is only localized or whether metastases have already formed.

In some cases, a tissue sample (biopsy) is first taken from the suspected area of the kidney to determine whether a mass is benign or malignant. This can be performed using an ultrasound-guided or CT-guided puncture under local anesthesia. A pathologist then analyzes the sample under a microscope. In addition to exact cell typing, conclusions can also be drawn about the aggressiveness and spread of the kidney cancer.

Finally, the kidney tumor is divided into different stages – depending on the size, aggressiveness and spread of the tumor (so-called TNM classification). Further treatment and the prognosis of the disease depend on this.

Kidney tumor: prognosis

The decisive factor is how advanced the cancer is at the time of diagnosis. If metastases have already formed in other organs, such as the liver, lungs or bones, the prognosis is less favorable. However, age and existing underlying illnesses also influence the course of the disease and the chances of survival.

Kidney tumor: Treatment

Treatment for kidney cancer depends on the stage and spread of the disease.

• Surgery ((partial) nephrectomy): This is the most important and only curative treatment method for localized tumour disease. As a rule, an attempt is made to operate as gently as possible on the kidneys and to preserve as much kidney tissue as possible. In the case of small tumors, partial removal of the kidney (partial nephrectomy) is often sufficient. Sometimes even minimally invasive keyhole surgery is possible. In the case of larger or unfavorably located tumors, the complete removal of the kidney including the malignant tumor and lymph nodes may be necessary as part of an operation (radical nephrectomy). Because the second kidney is only very rarely affected, it takes over the function of the missing kidney. The prerequisite is good kidney function prior to the operation.
• Radiofrequency ablation: Smaller kidney tumors can be “cooked” by heat and the cancerous tissue dies in the process – however, a tissue sample must first be taken to ensure that it is a malignant tumor.
• CryotherapyCold treatment, in which the cancerous tissue is “frozen”, is also suitable for smaller kidney tumors.
• Embolization, if surgery is not possible. This closes the vessels leading to the tumor.
• Immunotherapy: The drugs do not target the cancer cells themselves, but are intended to activate the patient’s own immune system to take action against malignant tumor cells. The so-called checkpoint inhibitors (PD-1; PD-L1 inhibitors) are used. These are used either in combination or alone or in combination with tyrosine kinase inhibitors in the first line and are firmly anchored in the guidelines.
• Tyrosine kinase inhibitors (“targeted therapy”): these drugs belong to the group of so-called angiogenesis inhibitors. They prevent the formation of new blood vessels, which the tumor needs for its oxygen and nutrient supply – so the drugs “starve” it out.
• Radiotherapy: Cancer cells are treated using high-energy radiation. They damage the genetic material of the tumor cells. The cancer cells can hardly repair this damage – they die. Radiotherapy is usually used for metastases on the bone or for small kidney tumors that cannot be operated on.
• Chemotherapy: it plays no role in this disease and is not used.
• Wait and see (“watchful waiting”): This strategy is sometimes chosen for metastases if they are only present in small numbers, are very small and grow very slowly.

All therapies can potentially cause side effects.

Regular follow-up care is important for any cancer – including kidney cancer. Please visit us for check-ups at certain intervals. It is checked whether the cancer has returned (relapse, recurrence). In addition, your general state of health will be assessed and any side effects, consequences and complications of the therapies will be treated. Initially, checks are carried out approximately every three months. Later, the time intervals are extended if you have not had a relapse. Discuss with your attending physician how often follow-up appointments are advisable.