Kidney Cancer – Diagnosis and Treatment of Renal Cell Carcinoma

Kidney cancer (also known as renal cell carcinoma or, for short, renal carcinoma) is a malignant tumor of the kidney. About 2 to 3 percent of all malignant tumors in adults are renal carcinomas. The average age of onset for renal carcinoma is around 65 to 70 years.

Kidney cancer is often discovered incidentally during imaging tests performed for other reasons. In most cases, the tumor is still in an early stage at that point. This increases the chances of a cure.

Although the causes of malignant tumors in the kidneys are not yet fully understood, certain factors are known to increase the risk of kidney cancer. These include, for example,

• tobacco use,
• the use of certain pain medications,
• an existing kidney condition (chronic kidney disease),
• obesity, and
• exposure to chemical substances such as asbestos, cadmium, and solvents.

Hereditary factors can also play an important role in the development of cancer.

Initially, kidney cancer causes few or no noticeable symptoms. However, if the disease has already progressed, it can lead to pain in the kidney area and visible traces of blood in the urine.

In addition, other symptoms may occur, such as

• weight loss,
• fatigue
• fever, and
• night sweats.

Occasionally, a mass—that is, a lump or swelling—can be felt in the flank area.

If metastases have formed, the symptoms depend mainly on the affected organ:

• Bone metastases: bone pain,
• Metastases in the lungs: cough and shortness of breath,
• Metastases in the liver: elevated liver enzymes with jaundice,
• Brain metastases: neurological deficits.

The location of the kidneys in the body and a microscopic view of kidney cancer tissue © Dr_Microbe | AdobeStock

Kidney cancer does not cause any symptoms in the early stages. Doctors therefore often discover the first signs of kidney cancer by chance as a result

• an MRI scan,
• a computed tomography (CT) scan, or
• an abdominal ultrasound.

However, some patients also see a doctor because of blood in their urine or flank pain.

Diagnosis begins with a thorough medical history (questioning the patient about risk factors). This is followed by a physical examination and a test for blood in the urine. An ultrasound of the kidney and abdomen and a contrast-enhanced computed tomography (CT) scan can confirm or rule out the initial suspicion. The CT scan also provides information on how far the renal cell carcinoma has already spread. An MRI is usually ordered if tumor-related vascular occlusions are suspected. 

An assessment of tumor spread and the search for metastases is performed using

• MRI,
• bone scan, and
• a CT scan of the skull

.

Based on the diagnosis of kidney cancer and the assessment of its spread, the kidney cancer specialist can determine the stage.

• Early tumor stage: A smaller tumor that is locally confined (lymph nodes or adjacent tissues are not yet affected)
• Advanced stage: Involvement of the lymph nodes and/or formation of metastases

Classifying the cancer into a specific stage plays a major role in treatment and prognosis.

There are three treatment options available. Surgery for kidney cancer is the only curative (healing) option among them.

• Kidney cancer surgery: Removing the kidney carcinoma offers the prospect of a complete cure. In some cases, it may be necessary to remove part or even the entire kidney (known as a nephrectomy). The procedures are performed either as open surgery or using minimally invasive techniques such as laparoscopy or robotic surgery.
• Chemotherapy: If the renal cell carcinoma has not yet metastasized, kidney cancer specialists currently do not recommend chemotherapy after surgery (adjuvant chemotherapy). Results from clinical trials on neoadjuvant chemotherapy (chemotherapy before surgery) are still pending. However, if metastases have formed, drug therapy is necessary. Various medications are available for this purpose, which must be administered according to a specific regimen.
• Radiation therapy: Renal cell carcinoma is relatively resistant to radiation therapy. It is therefore not used as a curative treatment but rather, in most cases, only as a palliative measure—for example, to manage pain.

Specialists in kidney cancer are medical oncologists. They work as part of an interdisciplinary team with specialists from other fields, such as

• nephrologists,
• surgeons specializing in oncological surgery, and
• urologists.

Patients with renal cell carcinoma should seek treatment at specialized kidney cancer centers. These centers ensure a high standard of care for kidney cancer. In addition, patients often have the opportunity to benefit from the latest therapies by participating in clinical trials.

The prognosis depends primarily

• on the stage (I through IV) determined at the time of diagnosis and
• the histological subtype

. The patient’s age at diagnosis and other underlying medical conditions (comorbidities) can also have a positive or negative impact. The more advanced the stage, the more difficult it is to treat kidney cancer and the poorer the prognosis.

In Germany, the 5-year survival rate ranges from 65 to 75 percent. If metastases are already present, the average life expectancy is 24 to 30 months.

In general, there are no specific recommendations for follow-up care after surgical tumor removal.

According to current guidelines, a risk profile (low, medium, high) can be established for each patient. Follow-up care is then tailored based on the patient’s symptoms and the likelihood of metastasis.

Physical examinations, laboratory tests, and new imaging studies are performed at regular intervals.

A kidney tumor often goes unnoticed for a long time, which is why typical symptoms frequently do not appear until later stages. The risk of kidney cancer increases due to factors such as smoking, obesity, and high blood pressure, with men being affected more frequently than women. The most common form of kidney cancer is renal cell carcinoma, which is often discovered incidentally in many patients during an ultrasound or CT scan. If kidney cancer is suspected, prompt diagnosis and treatment are crucial for detecting metastases early and improving the chances of recovery.

Whether kidney cancer is treated surgically or with medication depends on the size of the tumor and whether metastases have already formed. For small tumors, removal of the tumor—or, in some cases, removal of the kidney—is often necessary. For metastatic kidney cancer, and when metastases are already present in the bones or other organs, modern therapies are available to alleviate symptoms and maintain quality of life. For patients with kidney cancer, treatment is often provided through an interdisciplinary approach involving oncology, urology, and the patients’ primary care physicians.

Today, people with kidney cancer also benefit from improved drug therapies and modern approaches to counseling and treatment. German Cancer Aid and the Cancer Information Service of the German Cancer Research Center provide comprehensive information on the causes of kidney cancer, treatment options, and rehabilitation after kidney cancer. Since kidney cancer can develop without causing early symptoms, typical symptoms should be taken seriously. Although a diagnosis of kidney cancer is a major burden for those affected, individually tailored therapies and early treatment can significantly improve the prognosis.