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Renal Cell Carcinoma

Renal cell carcinoma (RCC) is a malignant neoplasm arising from the epithelial cells of the renal tubules. Accounting for approximately 85% of all malignant renal tumors, it is the most common form of kidney cancer and represents around 2–3% of all solid malignancies in adults.

In Germany, approximately 15,000 people are newly diagnosed with renal cell carcinoma each year. Men are affected approximately twice as often as women. Peak incidence occurs between 60 and 75 years of age.

As abdominal ultrasonography and cross-sectional imaging have become widely available, more than 50% of renal cell carcinomas are now detected incidentally at an early, asymptomatic stage. This has substantially broadened the available treatment options.

Histological Subtypes

  • Clear cell renal cell carcinoma (ccRCC): 75–80% (frequent VHL alterations; may respond to immunotherapy and tyrosine kinase inhibitors)
  • Papillary renal cell carcinoma (pRCC), types 1 and 2: 10–15% (frequently multicentric; MET alterations may occur in type 1)
  • Chromophobe renal cell carcinoma (chRCC): approximately 5% (generally more favorable prognosis; distinction from renal oncocytoma is important)
  • Collecting duct carcinoma: <1% (aggressive clinical course)

Risk Factors

  • Smoking, which approximately doubles the risk of disease
  • Overweight and obesity
  • Arterial hypertension
  • Family history and hereditary syndromes, e.g. von Hippel–Lindau syndrome and hereditary papillary renal cell carcinoma
  • Long-term dialysis with acquired cystic kidney disease
  • Exposure to compounds containing trichloroethylene or cadmium

Approximately 30% of renal cell carcinomas are not diagnosed until metastatic disease is already present. A further 20–30% of patients who initially undergo surgery for localized disease subsequently develop distant metastases, most commonly in the lungs, bones, liver, adrenal glands, and brain.

Symptoms and Their Development

Because diagnostic imaging is now widely used, renal cell carcinoma is frequently detected in asymptomatic patients. Clinical manifestations usually develop only once the tumor is more advanced.

Classical Symptoms

  • Hematuria (visible or microscopic blood in the urine) – caused by tumor extension into the renal pelvis or collecting system
  • Flank pain – caused by distension of the renal capsule or passage of blood clots through the ureter
  • Palpable renal mass – typically associated with large or advanced tumors

The classical triad of hematuria, flank pain, and a palpable renal mass is now regarded as a late manifestation and is present in only approximately 6–10% of patients.

Paraneoplastic Syndromes

Renal cell carcinoma is associated with a broad spectrum of paraneoplastic syndromes resulting from tumor-related hormone and cytokine production.

  • Persistent elevation of body temperature or fever of unknown origin
  • Arterial hypertension due to tumor-associated renin production
  • Erythrocytosis/polycythemia due to erythropoietin secretion
  • Hypercalcemia due to PTHrP secretion
  • Stauffer syndrome: reversible hepatic dysfunction in the absence of liver metastases
  • Weight loss, night sweats, and fatigue

Symptoms Caused by Metastases

  • Bone metastases: bone pain and pathological fractures
  • Lung metastases: cough, dyspnea, and hemoptysis
  • Brain metastases: headache, neurological deficits, and seizures
  • Adrenal metastases: frequently asymptomatic
  • Left-sided varicocele: sudden onset may indicate tumor thrombus within the left renal vein

Diagnosis

The diagnosis of renal cell carcinoma is based on imaging and laboratory investigations. Biopsy is indicated in selected situations but is not routinely required.

  • Renal ultrasonography: frequently the first imaging examination; enables differentiation between solid and cystic renal lesions. Renal cysts are assessed using the Bosniak classification.
  • Contrast-enhanced CT of the abdomen and chest (triphasic CT): standard imaging for tumor characterization, assessment of the extent of venous tumor thrombus involving the renal vein or inferior vena cava, and staging.
  • Renal MRI: complementary examination in patients with intolerance or contraindication to iodinated contrast material, suspected venous tumor thrombus, or indeterminate CT findings.
  • Chest CT: performed to exclude pulmonary metastases.
  • Bone scintigraphy / PET-CT: used when bone or other distant metastases are suspected.
  • Brain MRI: indicated in patients with neurological symptoms or high-risk disease to exclude brain metastases.
  • Laboratory investigations: creatinine, glomerular filtration rate (GFR), complete blood count, LDH, calcium, liver function tests, and urinalysis.
  • Biopsy: percutaneous CT- or ultrasound-guided biopsy, indicated when systemic therapy is planned without surgery or when imaging findings are inconclusive.


In addition, the anatomical extent of the tumor is assessed using the TNM classification (simplified).

  • T describes the local extent and size of the primary renal tumor (for example, tumors ≤7 cm versus >7 cm while confined to the kidney).
  • N describes involvement of regional lymph nodes.
  • M describes the presence of distant metastases.

Left: In this case, a 72-year-old male patient with right-sided renal cell carcinoma underwent radiosurgical treatment in June 2024.

Right: Five months after a single CyberKnife® treatment session (treatment duration: 30 minutes), MRI demonstrated a marked reduction in tumor volume of approximately 80%, indicating a pronounced local treatment response. Follow-up imaging can now be performed at annual intervals.

Treatment Options

Treatment decisions in renal cell carcinoma are made on an interdisciplinary basis and depend on tumor stage, histological subtype, the patient's general condition, and the function of the contralateral kidney.

“Watch & Wait” (Active Surveillance)

  • For small tumors <3 cm (T1a), particularly in older patients or those with multiple comorbidities
  • Regular imaging surveillance
  • Initiation of treatment if tumor growth or symptoms occur

Surgical Resection

  • Partial nephrectomy (nephron-sparing surgery) – standard treatment for T1 tumors where technically feasible
  • Radical nephrectomy for large or centrally located tumors
  • Open, laparoscopic, or robot-assisted approaches
  • Thrombectomy where indicated in the presence of venous tumor thrombus

Thermal Ablation

  • Radiofrequency ablation (RFA) or cryoablation
  • For small tumors ≤3 cm in patients at increased operative risk
  • Percutaneous treatment under CT guidance

Systemic Therapy

  • Tyrosine kinase inhibitors (TKIs): sunitinib, pazopanib, cabozantinib
  • Immunotherapy (immune-checkpoint inhibitors): nivolumab, pembrolizumab
  • Combination regimens in metastatic renal cell carcinoma
  • mTOR inhibitors: everolimus, temsirolimus

Radiosurgery

  • Non-invasive, high-precision irradiation using CyberKnife
  • Treatment of the primary tumor in patients who are medically inoperable or have a solitary kidney
  • Oligometastatic disease involving bone, brain, lung, or adrenal gland

CyberKnife

In contrast to conventional surgery, CyberKnife® treatment is performed on an outpatient basis. The robotically guided system delivers radiation to the tumor from multiple beam directions with submillimeter precision. This permits a steep dose gradient: a high radiation dose is concentrated within the tumor, while the dose decreases rapidly in the surrounding healthy tissue. Treatment is delivered with highly precise target localization, allowing adjacent organs and surrounding normal tissues to be selectively spared. Whereas conventional radiotherapy may require a prolonged

course of treatment, CyberKnife® treatment can be completed in only a few sessions. This reduces treatment burden and may improve comfort, quality of life, the ability to maintain normal daily activities, and overall tolerability. As the treatment is non-invasive, it avoids the surgical and anesthesia-related risks associated with an operative procedure.

Many patients can resume their usual daily activities immediately after treatment.

At the ERCM, patients have been successfully treated with radiosurgical techniques for more than 20 years.

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Frequently asked questions

Renal cell carcinoma is a potentially serious malignancy, particularly if it is not detected and treated at an

early stage. Prognosis depends on the stage and extent of the tumor.

Approximately 70% of renal cell carcinomas are asymptomatic and are detected incidentally on renal ultrasonography. Symptoms generally occur only at more advanced stages. Common manifestations include hematuria, pain, a palpable renal mass, and weight loss. When Can Renal Cell Carcinoma Be Treated with Radiosurgery? Robotically guided, high-precision CyberKnife® treatment may be considered—depending on the size and location of the tumor—when surgery is not desired or when the operative risk is considered too high.

Renal cell carcinoma may recur even after successful treatment. The individual risk of recurrence varies and depends on the type and stage of the original tumor, the effectiveness of treatment, and the patient's other medical conditions. Regular follow-up is therefore essential, as it enables recurrent disease to be detected and treated.

Yes. The most common sites of metastatic spread in renal cell carcinoma are the lungs, liver, bones, and brain.

Treatment Enquiries

Complex treatment options also mean that therapeutic decisions should always take the patient's individual circumstances and personal situation into account. We support you in this process and are available to provide individual, non-binding advice. For treatment enquiries, please use the contact form. You can also reach us by telephone during our opening hours or via our social media channels. Your enquiry will be reviewed individually and processed promptly.