About 10% of the total population suffers from chronic kidney disease – most of those affected are unaware of it. Even kidney cancer rarely causes clear symptoms in its early stages. For those affected, a cancer diagnosis is often a shock, coupled with an emotional rollercoaster. Here you'll find comprehensive information about symptoms, causes, and innovative, comfortable, and low-stress treatment options.
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Located on either side of the spine are the paired kidneys, which often receive little attention compared to other organs. Yet our kidneys are multitasking organs. They don't just produce urine, as is often assumed . Their diverse functions include, for example, regulating acid-base balance and blood pressure. The kidneys are also involved in the production of important hormones and the activation of vitamin D in the body.
According to the German Society of Nephrology (DGfN), kidney diseases are very common [1]. Sometimes, diffuse symptoms can become noticeable – even in severe kidney disease. Symptoms that are not usually immediately associated with the kidneys include fatigue and tiredness, unintentional weight loss, or fever.
Malignant neoplasms of the kidneys can originate from various tissues. Renal cell carcinomas (hypernephromas) are the most common of all kidney tumors in adults, accounting for approximately 95% [2, 3].
Unfortunately, 20 to 30% of all newly diagnosed patients already have metastases. In these cases, the cancer spreads to other organs and tissues of the body (e.g., the lungs or bones) [3, 4].
Due to medical progress and scientific developments in recent years, the therapeutic landscape has become significantly more complex today [3].
A wide range of treatment options are available for the various situations of kidney cancer – for the best possible therapy concept and an improved quality of life for affected patients.
Precision radiosurgery with the CyberKnife robotic system can often be used effectively to treat renal cell cancer, depending on the size and location of the tumor.
The innovative technology of radiosurgery has been tested at ERCM for many years and represents a long-term, effective, safe, and particularly gentle treatment for patients. [5, 6, 7]
Respiratory-mobile tumors in organs such as the kidneys can be treated with CyberKnife therapy without restraint or anesthesia [5]. If the CyberKnife is an option, often only a single treatment session is required to eliminate the tumor.
Treatment is performed on an outpatient basis, eliminating the need for hospitalization or the stress associated with surgery [5, 6]. In most cases, patients can resume their usual daily routine and activities following CyberKnife therapy.
Kidney cancer (renal cell carcinoma, also called renal adenocarcinoma) is a malignant tumor that usually originates from cells of the urinary tubules (tubule cells) or the epithelial cells lining the urinary tract. Typically, only one kidney is affected. In very rare cases (just under 1.5%), bilateral renal cell carcinomas are present, which often have genetic causes—i.e., are hereditary.
There were more than 14,000 new cases in Germany in 2020, with men being affected by kidney cancer about twice as often as women [2].
The disease is most frequently diagnosed around the age of 70. In children, which are very rarely affected, nephroblastomas (Wilms tumors) predominate, which are also malignant kidney tumors.
The further a renal cell carcinoma grows, the more sensitive structures and thus kidney function can be impaired.
In its early stages, renal cell cancer often causes no symptoms. As the tumor grows, flank or back pain may occur. Another warning sign may be blood in the urine. Tumors on the kidney can rarely be directly felt.
In men, a varicose vein rupture of the testicle can also be caused by renal cell cancer. Furthermore, it is advisable for men with an enlarged prostate (prostatic hypertrophy) to have their kidney function checked regularly. The same applies to patients with high blood pressure or gout, as well as those with other existing risk factors such as overweight and obesity.
The exact causes of renal cell carcinoma are unknown. Chronic renal failure, for example, represents permanent, severe damage to the kidneys and promotes tumor development in the organ.
Chronic renal failure, in turn, can be caused by medications that damage the kidneys (such as certain painkillers, anti-rheumatic drugs or antibiotics), as well as by recurrent inflammation of the urinary tract.
Overall, there are various factors that increase the risk of developing kidney cancer. These include smoking, obesity, and high blood pressure. However, some renal cell carcinomas also develop in complex, hereditary diseases.
The most important risk factors associated with kidney cancer are [2, 8]:
Another aspect is certain solvents to which people are occupationally exposed, even though these substances are now subject to strict regulations (e.g., trichloroethylene). Such substances can trigger kidney cancer, which in these cases can also be recognized as an occupational disease [2, 8].
Inherited kidney cancer can occur even at a younger age: By far the most common form of hereditary renal cell carcinoma is Von Hippel-Lindau syndrome, which is caused by a gene mutation [8]. Gene carriers have up to a 70% increased risk of developing kidney cancer up to the age of 60 [8].
Even for patients who have received a kidney transplant, the risk of developing renal cell carcinoma is up to 6 times higher than in the general population [9].
Modern diagnostic techniques have also contributed to the improved prognosis for primary kidney cancer: Approximately 60% of cases can be detected at an early stage using imaging techniques and thus treated early [2]. If a diagnosis is suspected, ultrasound or computed tomography (CT) scans are used.
Further examination methods depend on your individual patient history. Magnetic resonance imaging (MRI) or bone scintigraphy may be necessary to confirm the diagnosis and determine how far the cancer has spread throughout the body [4].
Additional tests include the determination of relevant laboratory parameters, including urine and blood tests.
Left: In this case of a 72-year-old male patient with right renal cell carcinoma, radiosurgical treatment was performed in June 2024.
Right: Five months after CyberKnife therapy in a single session (treatment duration: 30 minutes), the tumor showed a significant volume reduction of approximately 80% on an MRI scan and has already been eliminated. Regular follow-up intervals can now be performed annually.
Various treatment options are available for kidney cancer. Depending on the individual situation, these methods can be combined within a multimodal treatment strategy to ensure the best possible outcome and, above all, improve quality of life [4].
These treatment options include surgery, systemic therapies and other local treatment options, as well as high-precision radiosurgery.
This operation remains the standard medical procedure to date. For tumors discovered at an early stage and not yet too large in diameter, kidney-preserving surgery can be performed. Experts refer to this as a partial nephrectomy—for example, even in cases where kidney function is already severely impaired.
However, the kidney is often removed completely, especially if the tumor has affected the entire kidney (simple nephrectomy). If the tumor is larger and cancer cells have already invaded neighboring tissue, the adrenal gland and surrounding lymph nodes are also removed (radical nephrectomy). Such procedures can be performed either openly – opening the body cavity through a large incision – or minimally invasively [8]. In contrast to open surgery, minimally invasive surgery (MIS) keeps skin incisions as small as possible.
If the remaining kidney cannot fully take over the function of the removed kidney after the operation, renal replacement therapy (dialysis) becomes necessary - this situation can now be avoided in some cases thanks to state-of-the-art technologies such as radiosurgery.
In recent years, a variety of new systemic therapies have also been established, which can often be used very effectively and specifically at different stages of the disease. However, since new findings on this topic are emerging very rapidly these days, it is absolutely essential that you consult a uro-oncologist – a specialist in the field of urinary tract cancer – to obtain comprehensive information and discuss the latest scientific and clinical findings.
In general, individually tailored treatment concepts should always be discussed with your treatment team and the uro-oncology experts. Here at ERCM, for example, we collaborate with specialists at the Großhadern Hospital of the University of Munich (LMU).
Kidney tumor cells are generally less sensitive to radiation than cells of other tumors. Therefore, conventional radiation therapy, which is often administered over several weeks in multiple sessions (fractionated), is generally not recommended for the treatment of kidney cancer.
In certain cases, renal cell carcinomas can be treated alternatively with radiofrequency ablation (RFA) or cryotherapy [8]. These thermal methods involve the placement of fine probes into the tumor using imaging techniques. The goal is to destroy the cancer cells either by applying heat (radiofrequency at temperatures above 100°C) or cold (-60°C to -70°C).
However, both methods have limitations, as they can usually only treat smaller kidney tumors and those located outside the ureter and vascular structures [6]. Furthermore, the procedures are invasive and require access to the kidney through appropriate skin incisions. This can be problematic for many affected patients, for example, if they must take anticoagulant medication continuously [6].
Active surveillance is a therapeutic strategy for patients with small renal tumors (less than 4 cm) who refuse surgical treatment or are not eligible for it {8}. Active surveillance may also be an option for older patients at an early stage of the disease, depending on other pre-existing conditions, among other factors.
To minimize the risk of uncontrolled tumor growth, follow-up examinations are required at intervals of approximately 3 months.
Our experience with the CyberKnife system shows success rates of over 90% [6, 7, 10, 11, 12].
Which renal cell carcinomas should be treated surgically and which with radiosurgery? We are frequently asked this question. A comprehensive discussion and consultation with the entire treatment team are crucial for making a treatment decision. This includes, in particular, our colleagues in urology. Depending on your age, for example, but also on the size and location of the tumor, we will always work with you to determine the most appropriate treatment plan.
Radiosurgery represents a highly effective, high-precision treatment approach using high-dose photons, usually in a single treatment session (30 minutes) [5, 6]. This effectively eliminates the kidney tumor. Various immunological and directly cell-destructive processes play a role in this process. Healthy surrounding tissue is maximally protected [6] .
Careful professional coordination within your individual treatment team is particularly important for an optimal course of treatment. We work closely with our partners at the Interdisciplinary Center for Kidney Tumors (IZN) at the University Hospital of Munich (LMU), who specialize in the various situations associated with renal cell cancer.
In summary, high-precision treatment represents a very good alternative for selected patients – in the future, it could also play a role as a minimally invasive treatment option for renal pelvis tumors in patients who would otherwise not be effectively treated [11, 12, 13].
What’s special about CyberKnife therapy is that, using this special technology, the tumor can be targeted and eliminated with an accuracy of less than 1 mm – even though the kidney is constantly moving due to natural breathing. Breathing movements are thus precisely compensated for: The robot constantly moves with the kidney in all planes.
To achieve this high-precision adjustment, a breathing model is created prior to the radiosurgical treatment: The robot learns how you breathe and how the tumor to be treated moves. During the therapy session, these movements can then be monitored and continually adjusted by the robot system at any time – in fractions of a second.
Answers to frequently asked questions for kidney cancer patients: What is treatment like at a renowned clinic? What options does modern medicine offer? How do doctors respond to individual situations? How do they cooperate with colleagues in radiosurgery? Can one kidney be preserved? What about quality of life? How important are new methods such as radiosurgery with CyberKnife in today's treatment?
Renowned urologist and kidney cancer specialist Prof. Michael Staehler, MD, from the Urology Clinic and Polyclinic at the Großhadern Campus of the University of Munich Medical Center provides answers to these questions in an interview.
We will work with you to determine whether treatment with high-precision radiosurgery is suitable for you. The increasing complexity of treatment options means that the decision for a specific treatment should always be made with your personal circumstances in mind.
It is important to us that you and your family and loved ones understand all aspects of your illness and its treatment options and are able to classify them for yourselves.
For treatment inquiries, please use the contact form. You can also reach us by phone during our opening hours or via our social media channels.
Your request will be processed individually and promptly.
Renal cell carcinomas can be dangerous, especially if not detected and treated early. The prognosis depends on the stage and spread of the tumor. In advanced stages, renal cell cancer can be aggressive and spread to neighboring organs or other parts of the body.
Approximately 70% of renal cell carcinomas are asymptomatic and are discovered incidentally during renal ultrasound. Symptoms only appear in later stages. Common symptoms include hematuria (blood in the urine), pain, palpable tumors, and weight loss.
The growth rate can vary from case to case. Some tumors grow slowly, while others are more aggressive and can spread more quickly. Individual progression depends on the type of tumor, its stage, and other individual factors.
In cases of unclear mass lesions, a biopsy should be performed according to medical guidelines if the sampling could influence the choice of treatment.
Robot-guided precision treatment with the CyberKnife may be considered for some patients (e.g. depending on the size and location of the tumor), for example if there is an increased surgical risk or if surgery is not desired. If surgery can be avoided in an individual case, the diseased organ can often be preserved.
Even after successful treatment, kidney cancer can recur. The risk of recurrence depends on several factors, including the type and stage of the original tumor, the effectiveness of treatment, and overall health. Regular follow-up is therefore crucial to detect changes in the kidneys at an early stage and to treat recurring tumors (recurrences).
Yes, renal cell carcinomas have the potential to metastasize. This means that cancer cells can spread to other organs or tissues in the body. The most common sites for metastases are the lungs, liver, bones, and brain. The spread of metastases can worsen the prognosis, which is why early detection of kidney cancer is so crucial.
[1] Pressemeldung vom 6.10.2023, Nierenkrankheiten: Häufig, teuer und unterschätzt, Pressestelle Deutsche Gesellschaft für Nephrologie e.V., Berlin 2023; verfügbar unter: https://www.dgfn.eu/pressemeldung/pm-20231006-02-nierenkrankheiten-unterschaetzt.html [letzter Zugriff 27.11.2024]
https://www.dgfn.eu/pressemeldung/pm-20231006-02-nierenkrankheiten-unterschaetzt.html
[2] Robert Koch-Institut (Hrsg.) und die Gesellschaft der epidemiologischen Krebsregister in Deutschland e.V. (Hrsg.), Krebs in Deutschland für 2019/2020 (14. Ausgabe), Berlin 2023; ISBN 978-3-89606-323-6.
https://www.krebsdaten.de/Krebs/DE/Content/Publikationen/Krebs_in_Deutschland/krebs_in_deutschland_node.html
[3] Foller, S., Leucht, K., Grimm, M. O., Risikostratifizierung und Therapiealgorithmus des metastasierten Nierenzellkarzinoms, Die Onkologie. 2022;28(2):167-178.
https://doi.org/10.1007/s00761-021-01062-y
[4] Grünwald, V., Eberhardt, B., Bex, A., Flörcken, A., Gauler, T., et al., An interdisciplinary consensus on the management of bone metastases from renal cell carcinoma, Nat Rev Urol. 2018;15:511-521.
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[5] Siva, S., Kothari, G., Muacevic, A., Louie, A. V., Slotman, B. J., et al., Radiotherapy for renal cell carcinoma: renaissance of an overlooked approach, Nat Rev Urol. 2017;14:549-563.
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[6] Siva, S., Louie, A. V., Warner, A., Muacevic, A., Gandhidasan, S., et al. Pooled analysis of stereotactic ablative radiotherapy for primary renal cell carcinoma: A report from the International Radiosurgery Oncology Consortium for Kidney (IROCK), Cancer 2018;124:934-942.
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[7] Siva, S., Ali, M., Correa, R. J. M., Muacevic, A., Ponsky, L., et al., 5-year outcomes after stereotactic ablative body radiotherapy for primary renal cell carcinoma: an individual patient data meta-analysis from IROCK (the International Radiosurgery Consortium of the Kidney), The Lancet Oncology 2022;23(12):1508-1516.
https://doi.org/10.1016/S1470-2045(22)00656-8
[8] Leitlinienprogramm Onkologie (Deutsche Krebsgesellschaft, Deutsche Krebshilfe, AWMF), S3-Leitlinie Diagnostik, Therapie und Nachsorge des Nierenzellkarzinoms 2023: Langversion 4.0, AWMF-Registernummer: 043-017OL https://www.leitlinienprogramm-onkologie.de/leitlinien/nierenzellkarzinom/ [letzter Zugriff 27.11.2024]
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[10] Siva, S., Correa, R. J. M., Ali, M., Muacevic, A., Ponsky, L., et al. Long-Term Outcomes of SABR to Primary Renal Cell Carcinoma: A Multicenter Analysis from IROCK (International Radiosurgery Oncology Consortium for Kidney), Int J of Radiation Oncology. 2022;114(3) Suppl.:77.
https://doi.org/10.1016/j.ijrobp.2022.07.476
[11] Correa, R. J. M., Louie, A. V., Zaorsky, N. G., Lehrer, E. J., Ellis, R., et al., The Emerging Role of Stereotactic Ablative Radiotherapy for Primary Renal Cell Carcinoma: A Systematic Review and Meta-Analysis. European Urology Focus. 2019;5(6):958-969.
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[12] Staehler, M. D., Karl, A., Bader, M., Stief, C. G., Wowra, B., Muacevic, A., Single-fraction radiosurgery for the treatment of renal tumors in singular renal units, Journal of Clinical Oncology. 2011;29(15).
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[13] Staehler, M., Kufeld, M., Karl, A., Roosen, A., Bader, M., Muacevic, A. Cyberknife radiosurgery of a renal pelvis tumor to avoid hemodialysis - a case report. Cureus. 2010;2(11):17.
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