Renal cell carcinoma is a malignant tumor that originates from the tubular cells of the kidneys. The majority of all kidney tumors are renal cell carcinomas.
What is renal cell carcinoma?
About three percent of all malignancies in adults are renal carcinomas. Nine out of every 100,000 people develop renal cell carcinoma each year. Most people develop the disease between the ages of 40 and 70. Renal cell carcinoma, also known as Grawitz tumor, originates in the tubular cells of the kidney. Depending on the initial tissue, cytogenetic findings and histological picture, different renal cell carcinomas can be distinguished. The most common is classic renal cell carcinoma. It is also called clear cell carcinoma. Other forms of renal cell carcinoma are chromophilic or papillary carcinoma and chromophobe carcinoma. Rather rarely, ductal Bellini carcinoma develops. It is also known as collecting duct carcinoma.
Causes
The exact etiology of renal cell carcinoma is still unclear. What is known is that men develop the disease significantly more often than women. Patients suffering from Hippel-Lindau syndrome develop the disease in a cluster. Hippel-Lindau syndrome is an autosomal-dominant inherited disorder associated with vascular malformations in the face and central nervous system. Risk factors for renal cell carcinoma include advanced age, chronic renal failure, smoking, lead exposure, cadmium exposure, long-term therapy with pain medications, congenital tuberous sclerosis, and exposure to trichloroethene.
Symptoms, complaints, and signs
Renal cell carcinoma usually does not cause symptoms until the tumor is quite large. There are usually no early symptoms. The tumor cells initially grow centrally in the parenchyma and thus have no connection to the tubular system of the kidney. Early-stage renal cell carcinoma is thus often only an incidental finding during an ultrasound examination of the abdominal organs. Nearly 70 percent of all kidney tumors are found incidentally during imaging examinations such as sonography, computed tomography or magnetic resonance imaging. A characteristic and threatening late symptom of renal cell carcinoma is blood in the urine. This so-called hematuria occurs suddenly and is painless. Other symptoms of renal cell carcinoma are rather non-specific. For example, the tumor may cause pain in the flank. Particularly pronounced tumors are palpable in the flank area. So-called B-symptoms may occur in the course of the cancer. These include weight loss, increased susceptibility to infection, night sweats and fever. Those affected are no longer as able-bodied as before. There may be anemia with fatigue, hair loss, difficulty breathing on exertion and severe pallor. If the tumor grows into the left renal vein or compresses the left renal vein, a varicose vein may develop on the testicle in the male. This is also called a varicocele. Rarely, paraneoplastic syndrome develops in renal cell carcinoma. Paraneoplastic syndrome is the term used to describe the accompanying symptoms of cancer that are not caused by the tumor. In renal cell carcinoma, paraneoplastic syndrome may be caused by tumor cells that produce hormones such as renin, erythropoietin, ACTH, or parathyroid hormone. Possible symptoms of such a paraneoplastic syndrome are hypertension, hyperthermia and cachexia. There is a possibility that Cushing’s syndrome may develop as a result of the elevated ACTH. Affected individuals have a full moon face, gain weight, exhibit what is called a bull neck, and suffer from muscle and heart weakness.
Diagnosis and course of the disease
Clinical examination with palpation, auscultation, and percussion reveals only large and advanced tumors of the kidneys. Hematuria is indicated by a pink coloration of the urine. With the aid of a urine stick, erythrocytes can be detected in the urine. The laboratory may show anemia, which is caused by the large amount of blood lost through the kidney. However, an ultrasound examination must be performed to confirm the diagnosis. Sonography is used to diagnose suspicious masses in the kidney. Subsequently, the conspicuous areas are punctured. The tissue material obtained is examined histologically by a pathologist. Most renal cell carcinomas have a lipid-rich and glycogen-rich cytoplasm.In order to assess the growth of the tumor, known as staging, a computed tomography scan of the abdomen is performed. The CT can also be used to determine the operability of the cancer tumor. With the help of chest X-rays, skeletal scintigraphy and brain MRI, distant metastases can be detected. However, X-rays only detect metastases that are larger than one centimeter in diameter. The 5-year survival rate for patients with renal cell carcinoma is about 50 percent.
Complications
Renal cell carcinoma can lead to severe complications, which is typical for tumors. For example, a large number of patients experience progressive metastasis to other organs. This is because malignant (malignant) kidney tumors tend to spread through the lymphatic and blood vessels in the body and form daughter tumors. In particular, the lungs, liver, brain and skin can be affected by additional tumors. Metastasis to the bones is also within the typical spectrum. As a result, renal cell carcinoma can lead to life-threatening complications, such as clots (emboli), clogged blood vessels, or pneumonia. The likelihood of metastasis to other organs increases significantly if renal cell carcinoma is not treated or is treated only very late. Early detection therefore plays an important role. In the course of medically indicated treatment, complications can also arise that are attributable to the substances taken. For example, it occasionally happens that the antiangiogenic antibody bevacizumab leads to thromboembolic events and perforations in the gastrointestinal tract.
When should you see a doctor?
Symptoms of renal cell carcinoma are often silent in the early stages of the disease. If the disease progresses, individual symptoms may become noticeable. With weight loss without reason or flank pain that becomes more severe, a doctor should be consulted. Fever that persists for a longer period of time should always be clarified by a doctor. A significant and prolonged decrease in performance may be a symptom of a serious illness. In such a case, a doctor should be contacted. Blood in the urine is also a reason to see a doctor. Seeing a doctor early can have a positive effect on the prognosis. If there is any uncertainty, a doctor’s appointment should be made promptly.
Treatment and therapy
The gold standard in the treatment of nonmetastatic renal cell carcinoma is surgical excision. Tumors no larger than seven centimeters are usually removed with kidney preservation. For larger tumors, the entire kidney must be surgically removed along with the adrenal gland, ureter, renal capsule and surrounding fatty tissue. If the tumor has grown into the renal vein or even the inferior vena cava, these tumor cones must also be removed. It may be necessary to use a heart–lung machine. New surgical procedures such as laparoscopic radical nephrectomy or minimally invasive procedures such as radiofrequency interstitial tumor ablation (RITA) are currently being researched and tested. Drug therapies are used for metastatic and locally inoperable renal cell carcinoma. Drug therapies are usually palliative in renal cell carcinoma, and a cure is usually no longer possible. Classical cytostatic drugs such as antimetabolites, alkylants, anthracyclines and mitotic inhibitors are ineffective in renal cell carcinoma. Renal cell carcinoma is therefore considered chemotherapy-resistant. Cancer immunotherapies are used instead of chemotherapies. Oral tyrosine kinase inhibitors, bevacizumab, and mTOR inhibitors are also used.
Outlook and prognosis
The prognosis for renal cell carcinoma depends largely on the timing of detection and the stage of the cancer. Metastatic renal cancer generally has a less favorable prognosis than pure, isolated renal cell carcinoma. Well-operable renal cell carcinomas that grow in one piece on the surface of the kidney have a particularly good prognosis. If these are surgically removed in a timely manner, recovery can be expected. Papillary and chromophobe types are also more often confined to the kidney (i.e., do not spread) and carry a good prognosis. The more lymph nodes are affected, the worse the prognosis. In the case of metastases, it is unfavorable overall.While a local tumor that has not spread still has a median five-year survival rate of 90 percent, it is only around 60 to 70 percent if the lymph nodes are involved. In the case of distant metastases, for example in the brain or lungs, the survival rate is only 15 percent. It should be noted that early detection is still the best influence on a favorable prognosis in renal cell carcinoma. Especially people with risk factors (genetic diseases, kidney weakness, etc.) benefit from control examinations. If carcinoma eventually occurs in the kidney, it can usually be treated quickly.
Prevention
Because the exact origin of renal cell carcinoma is as yet unclear, prevention is difficult. Risk factors such as long-term use of painkillers or smoking should be avoided.
Follow-up
Follow-up or aftercare is urgently required after any cancer therapy. This is due to the fact that many tumors reform after some time. In addition, there is a risk of metastasis growth, which regularly leads to a shortening of life expectancy. Follow-up care is usually arranged before the end of the initial therapy. The physician and patient determine the location and rhythm. Quarterly follow-up is common in the first year. After that, the interval increases from appointment to appointment. From the fifth year of freedom from symptoms, an annual visit is sufficient. This type of follow-up is aimed at close monitoring of the patient to prevent complications from arising in the first place and to enable diagnosis at an early stage. The latter brings the best prospects of cure. Follow-up care includes a detailed interview and a physical examination. In addition, a blood test is usually performed. Imaging procedures such as a CT or MRI are used as needed. Follow-up care can also take on a palliative character. In this case, there is no longer any chance of a cure for renal cell carcinoma. Doctors try to enable the patient to lead a life free of symptoms. Medication and assistance in everyday life form an important foundation for this.
What you can do yourself
Pure self-help measures that have a medical or even therapeutic effect on renal cell carcinoma do not exist. There are no home remedies, exercises, or other measures that affected individuals can usefully take. Rather, experimental use of non-prescribed remedies and substances is discouraged. However, measures to manage pain can be taken if necessary. It is important that the agents used do not stress the kidney. It may help the patient to be very knowledgeable about renal cell carcinoma. This type of cancer is very well researched and the information is readily available. A knowledge of one’s disease makes the treatment as well as one’s condition more understandable and accordingly can help overcome fears. It also gives patients more confidence when talking to doctors if they are well informed themselves. Since renal cell carcinoma also puts a strain on the healthy parts of the kidney or kidneys, it is also advisable to adopt a kidney-friendly diet. This means a significant reduction in the amount of salt consumed and an increase in the amount drunk. The amount of salt should be around five grams or less per day, and the amount drunk should be increased to around 2.5 to 3 liters. The amount of meat in the diet can also be reduced to provide additional relief for the kidneys.