Kidney cancer (malignant kidney tumor) is a malignant growth of the kidney. It can originate from different cell types. The renal cell carcinoma, which is usually produced from cells of the urinary tubules, is most frequent. With approximately two per cent, renal cancer makes up only a very small part of all cancer. Read all the important facts about the possible causes, the therapy and the chances of recovery in kidney cancer.
Kidney cancer occurs when individual cells of the kidney change viciously (degenerate) and begin to proliferate unrestrainedly. The cancer can develop from different cell types. In about 95 per cent of the cases a renal cell carcinoma (renal carcinoma, adenocarcinoma of the kidney) is a malignant kidney tumor, which usually emerges from the cells of the urinary tubules (tubulous system). There are different types of renal cell carcinoma: the most common is the so-called clear-cell carcinoma; other forms include papillary carcinoma and ductal Bellini carcinoma. The latter is particularly aggressive and spreads quickly, but is rare.
In many cases the renal carcinoma is located at the lower pole of the kidney and points towards the pelvis. A bilateral attack of the left and right kidneys at the same time is very rare.
In addition to renal cell carcinoma, other malignant kidney tumors are also referred to as renal cancer. This includes, for example, renal cell carcinoma, which is, however, much rarer than renal cell carcinoma. Renal cell carcinoma develops from the tissues of the urinary tract, which arise from the kidneys. It can trigger symptoms similar to kidney cancer.
In some cases, a malignant kidney tumor appears as a secondary tumor (metastasis) of another type of cancer somewhere in the body, such as lung or breast cancer.
Why a kidney tumor is so dangerous
The kidneys are among the organs that are best per fused. As a result, proliferating cancer cells can spread very rapidly over the blood and lymph vessels in the rest of the organism and form daughter tumors. Such kidney cancer metastases arise mainly in the lungs, liver, brain and bones. Once initial metastases have formed, prognosis and treatment options are worsening for patients with a malignant renal tumor.
Facts and figures
Renal cancer represents a very rare form of cancer with about two per cent of all tumor diseases. In 2010, approximately 14,500 people in Germany suffered from renal cancer. The German cancer registry under the term “renal cancer” classifies all malignant diseases of the kidneys, kidneys and ureters. For 2014, experts predict a rise in new cases to 15,500 patients: 9,500 of them male and 6,000 female.
The risk for malignant renal tumors increases with age: young people are very rarely affected by renal cancer. The average age for diagnosis is 71 years for women and 68 for men.
Renal cancer: symptoms
All important to the typical signs of kidney cancer read in the article kidney cancer symptoms.
Kidney cancer: causes and risk factors
The causes of a tumor on the kidney are still largely unknown. However, there are some risk factors that favor the outbreak of kidney cancer. This includes acquired risk factors such as:
- Fat-rich, low-fiber diet
- Insufficient fluid intake
- Increased consumption of alcohol
- high blood pressure
- Chronic renal failure
- Acquired cystic kidney disease
- Misuse of painkillers
Rising age also increases the risk of renal cancer. Life expectancy and prognosis are usually dependent on possible accompanying diseases.
Also hereditary factors may contribute to the development of kidney cancer. A genetic predisposition is suspected in approximately one out of 100 affected persons. Some rare hereditary diseases such as tuberous sclerosis and von Hippel-Lindau disease are also associated with an increased risk of kidney cancer.
It has not yet been clarified whether people who are regularly exposed to certain chemicals such as asbestos, cadmium or lead also have an increased risk of disease.
Kidney cancer: examinations and diagnosis
In most cases the tumor on the kidneys is discovered accidentally in the course of other examinations – for example in an ultrasound examination. In other cases, there are already symptoms related to the tumor, which lead a patient to the doctor’s visit. In order to get to the root of the complaints, the doctor will usually first ask the patient’s medical history (anamnesis ). In doing so, he inquires about the type and extent of the complaints.
The next step is physical examination . First indications of kidney cancer can be a palpable resistance in the abdominal area, enlarged lymph nodes in the neck and neck area as well as conspicuous water accumulations (edema) in the legs. In men, a newly found varicose vein (varicocele) in the testes can also be a sign of kidney cancer.
All these signs can also be symptoms of other diseases. In order to clarify whether there is actually kidney cancer, there is therefore still further investigation. These provide, in part, other information which is important for the treatment planning (such as the size and position of the tumor, presence of metastases):
Laboratory investigations can cure suspected kidney cancer: the patient’s urine and blood tests are examined for specific changes such as, for example, altered renal function values in the blood or blood in the urine (hematuria).
A clear diagnosis is possible in most cases by means of an ultrasound examination (sonography) . A computed tomography (CT) can confirm the suspected renal cancer. An iodine-containing x-ray contrast agent must usually be used. If the patient does not tolerate this, a magnetic resonance tomography (MRT) can alternatively be performed. It can also effectively detect renal cancer. With such imaging methods, the size and position of the tumor can also be precisely determined. Metastases (eg in the bones) can also be detected. Bone metastases can also be detected by means of skeletal scintigraphy.
In rare cases it may happen that the vascular supply of the tumor must be determined before an operation. For this purpose angiography is carried out, an X-ray examination of the vessels by means of an X-ray contrast medium.
Sometimes a tissue sample (biopsy) of the nierentian is also taken with the help of a fine needle in order to examine it more precisely in the laboratory. This allows the physician to determine the type of tissue the tumor has developed. This may be important for therapy planning.
Further investigations may be useful in individual cases.
Renal cancer: treatment
The treatment of renal cancer primarily depends on the tumor stage. There is only one treatment method that can actually bring healing – the operative removal of the tumor . This is usually not a problem with small tumors. Therefore, it is important that the renal cancer is diagnosed early.
In some cases, the whole kidney, sometimes even the adrenal gland, must be removed. Wherever possible, however, a “kidney-conserving operation” is performed. This means: The surgeon tries to get as much healthy tissue as possible during surgery.
Even in a larger tumor or if metastases have already spread in the body, surgery is useful. Although it does not promise complete healing, it alleviates the pain (palliative therapy) and increases the success potential of further therapeutic measures. Such an operation is often followed by other therapies:
Within the scope of the targeted drug therapy , the kidney cancer patients are administered active ingredients which specifically alter or block the metabolism of the tumor cells. They prevent the renal carcinoma from growing further – the patient’s life expectancy increases. Known active ingredients are, for example, sunitinib, sorafenib, pazopanib, temsirolism and bevacizumab. Sometimes, several such active ingredients are combined to increase the success potential of the therapy.
Another treatment option for advanced renal cancer is immunotherapy . The immune system is stimulated with active substances such as interferon alpha or interleukin-2 in such a way that it detects, attacks and eliminates well-camouflaged cancer cells. This also prevents the kidney tumor from growing further. However, immunotherapy is only successful in some cases.
Another form of immunotherapy, which researchers are currently working on, uses the patient’s own cells to stimulate the immune system against renal cancer – certain white blood cells called dendritic cells. They play an important role for body defense by presenting prominent parts of, for example, cancer cells on their surface, thus signaling the defense cells against which “enemy” they must take action. Researchers want to use this mechanism in the treatment of kidney cancer (and other types of cancer): they load the patient’s dendritic cells with typical cancer cells and inject them into the skin. Inside the body, the “vaccinated” cells stimulate the immune system to attack the kidney cancer.
A radiation therapy can be used if the kidney cancer already metastases (metastases) has led. In particular, it should alleviate the patient’s discomfort; A cure is thus not possible – renal cell carcinoma (the most common type of kidney) is little sensitive to radiation.
Unlike other cancers is chemotherapy for kidney cancer hardly successful.
In some cases of renal cancer – for example, if surgery is not possible due to severe concomitant diseases – sometimes a so-called tumor embolism is performed. The physician closes the renal artery of the diseased kidney by means of a catheter. In this way the blood supply to the tumor is interrupted – it cannot grow any longer, in part it even forms itself back. However, the effect is not permanent and serves only to alleviate the symptoms.
Kidney cancer: disease history and prognosis
In the case of a kidney tumor the healing chances depend primarily on the size of the tumor on the kidney and how far it has spread at the time of the diagnosis. With the aid of modern ultrasound technology, even small tumors can already be seen in the initial stage. Those affected usually have a good prognosis. Because the earlier renal cancer is detected and treated, the better it can be treated. To detect renal cancer at an early stage, patients should seek immediate medical attention if signs such as blood in urine or frequent pain in the kidneys are present. These symptoms often occur in renal carcinoma but are not necessarily indicative of renal cancer.
Healing chances and life expectancy in a malignant kidney tumor also decisively depend on whether there are already metastases. Especially in the case of daughter tumors in the brain there is a small possibility to treat – the prognosis worsens clearly. In addition, the age of the patient and possible accompanying diseases have a further influence on the healing potential of renal cancer.
In general, 75% of men and 77% of women (relative 5-year survival rate) survive five years after the diagnosis of “kidney cancer”. An opportunity for complete healing has been given to those patients in whom renal cancer can be surgically removed