Wilms tumor (nephroblastoma) represents the most common tumor disease of the kidneys in children, affecting girls slightly more often than boys. If diagnosed early and therapy is started, Wilms tumor is usually curable in the long term.
What is a Wilms tumor?
Wilms tumor or nephroblastoma is a malignant (malignant) tumor of the kidney that primarily affects children, especially those between the ages of 1 and 4 years. A Wilms tumor is usually unilateral and tends to metastasize (form daughter tumors) early, often hematogenously (via the blood) to the lungs, brain, liver, as well as the regional lymph nodes. Furthermore, Wilms tumor is associated in some cases with concomitant congenital malformations, mainly affecting the eye (aniridia or missing iris) or the urethra (urogenital malformations). In addition, Wilms’ tumor is characterized mainly by painless tumor swelling in the abdominal wall area and is associated with pain, hematuria (blood in the urine), or hypertension (high blood pressure) only in rare cases.
Causes
The causes of a Wilms tumor have not yet been determined. Due to the fact that nephroblastoma can in many cases be associated with congenital concomitant malformations or genetic disorders such as Beckwith-Wiedemann syndrome, WAGR syndrome, or Denys-Drash syndrome, genetic factors are thought to be responsible for the manifestation of the tumor disease. It is suspected that the so-called Wilms tumor gene WT-1, which plays a significant role in the physiological formation of the kidney, and WT-2, which is also located on chromosome 11 like WT-1, may contribute to the manifestation of Wilms tumor. In addition, analysis of tumor cells revealed DNA loss on the short arm of chromosome 11, which is normally responsible for tumor suppression (suppression).
Symptoms, complaints, and signs
Wilms tumor (also called nephroblastoma) is a specific type of kidney tumor that occurs particularly in children. In 85 percent of cases, children suffering from Wilms tumor are younger than five years old.In 11 percent of all cases, Wilms tumor occurs without symptoms and was discovered by chance during a screening examination. When Wilms tumor does show symptoms, the main symptom is a painless bulging of the abdomen, which is a bulging of the abdominal wall. In some cases, children complain of pain. Often this bulging, “thick” abdomen is not recognized as a symptom but is seen as a sign of well-nutrition. In rare cases, blood is found in the child’s urine (hematuria). Untypical symptoms that may accompany nephroblastoma are fever, vomiting, problems with the digestive system, or high blood pressure (hypertension). Problems with the digestive system may include loss of appetite or alternating diarrhea and constipation. In rare cases, there may be an increased concentration of calcium in the blood (hypercalcemia). In rare cases, Wilms’ tumor also occurs in young or older adults. Here, it may be manifested by flank pain, a loss of weight, and the sudden drop in performance.
Diagnosis and progression
Because a Wilms’ tumor causes hardly any characteristic symptoms at the beginning, the tumor disease is diagnosed in many cases during a routine examination by palpation of the abdominal area. If a painless swelling is found, this may be the first indication of a Wilms tumor. Imaging procedures such as sonography (ultrasound), computer tomography (CT), X-ray examination and magnetic resonance imaging (MRI) are used to confirm the diagnosis. These simultaneously serve to determine the size and localization as well as the spread of the tumor (detection of metastases). In addition, kidney function can be checked by means of a creatinine clearance (determination of the creatinine concentration in urine or serum) as well as a kidney function scintigraphy (nuclear medicine procedure). Wilms’ tumor has a progressive course with rapid growth and tends to metastasize early. However, the prognosis is usually good with early diagnosis and initiation of therapy, and in about 90 percent of cases, affected children can be cured in the long term.
Complications
Wilms tumor is the most common form of kidney cancer in children.If the tumor is discovered in time and adequately treated, there is a good chance that the patient will recover completely and that no serious complications will develop. Nevertheless, crises must be expected during therapy. A very common complication that occurs with Wilms’ tumor is high blood pressure. The hormone-like enzyme renin, which is produced in increased amounts, causes vascular lumens to constrict, leading to an increase in blood pressure. In addition, renal hemorrhage can occur because the membrane of Bowman’s capsule is injured. The blood often initially collects in the renal pelvis, and blood clots can usually be detected in the urine. If the internal bleeding is very severe, this can lead to a drop in blood pressure and resulting unconsciousness in the patient. Even a life-threatening circulatory collapse cannot be ruled out in the case of very severe internal bleeding. As with many malignant ulcers, Wilms’ tumor is at risk of spreading. Metastases usually form in the lungs, causing the patient to experience chest pain, shortness of breath, and bloody sputum before more severe complications develop.
When should you see a doctor?
If children show unusual behavior, parents should always pay increased attention to the behavior or health developments in the child. In the case of whiny behavior, severe restlessness or sleep disturbances, a doctor should be consulted. If unnatural changes, swellings or bulges develop on the body, these should also be clarified as soon as possible. In case of complaints such as vomiting, nausea or disorders of the digestive tract, the child needs medical care. Loss of appetite, constipation or irregularities of the heart rhythm are warning signals of the organism. A doctor should be consulted, as serious complications may arise if the disease does not progress favorably. If existing symptoms persist over a longer period of time, if new symptoms develop or if the intensity of the irregularities increases, a doctor should be consulted immediately. In case of fever, blood in the urine as well as disturbances of concentration and attention, action is required. Pain and the adoption of a physically protective posture should be examined more closely and treated. If the physical as well as the mental performance decreases, this indicates a health impairment. Sudden changes in particular are cause for concern. If participation in social life declines and the child’s playfulness has decreased within a short time, a doctor should be consulted. If there is a loss of weight, a visit to the doctor is also necessary.
Treatment and therapy
Therapy for a Wilms tumor usually involves surgical removal of the tumor-bearing kidney (tumor nephrectomy) as well as chemotherapy and radiation therapy. The individual measures and their sequence are adapted to the age of the affected child as well as the tumor condition and the stage of development of the disease. In children younger than six months, for example, the tumor-bearing kidney is surgically removed directly. However, prior to the surgical intervention, it should be checked whether the second kidney is fully functional. In older patients or patients with a larger nephroblastoma, the Wilms tumor is first reduced in size by chemotherapeutic measures before it is surgically removed in a tumor nephrectomy. If both kidneys are affected, surgery is aimed at preserving the kidneys and, following chemotherapy, only the remaining tumor remnants and metastases are removed from the unaffected kidney tissue (tumor enucleation). In rare cases (e.g. advanced stage of the disease or high malignancy of the Wilms tumor), radiation therapy is also required to kill tumor remnants or metastases that could not be removed by surgery or chemotherapy. Furthermore, after successful therapy, affected children should be monitored regularly for recurrences (recurrence of the tumor) during follow-up examinations, especially within the first two years after the end of therapy.
Prevention
Because the causes of Wilms tumor are unknown, nephroblastoma cannot be prevented.Children affected by genetic disorders that appear to favor tumor disease (including Beckwith-Wiedemann syndrome) should be examined by a physician for a possible Wilms tumor if swelling occurs in the abdominal region. In individual cases, molecular genetic testing may be required to determine a predisposition (disposition) to Wilms tumor.
Follow-up
Following the actual treatment of Wilms tumor, follow-up care of affected children is necessary. If a solid tumor has been surgically removed, specialists in oncology and hematology at Children’s Hospital will take care of the aftercare. In most cases, radiation treatment is no longer necessary after chemotherapy and surgery. The extent and type of aftercare depend on the particular stage of the Wilms tumor. Since this period is extremely stressful for the affected children and their families, psychosocial care is useful. Qualified psychotherapists show both the sick child and his or her parents and siblings how to cope better with the difficult situation. Control examinations are also an important part of aftercare. They must take place regularly because a recurrence of the cancer is possible in the two years following therapy. If an ulcer does indeed reappear, it can be treated at an early stage. The close-meshed examinations include sonography (ultrasound examination). Magnetic resonance imaging is also possible. If the suspicion of a recurrence is confirmed, it is again treated with chemotherapy. Follow-up care also includes regular monitoring of the lungs by X-ray examinations. In the first two years after cancer therapy, there is a risk of metastases (daughter tumors) in the lungs. If there are no recurrences or metastases after five years, the child is considered cured, so there is no need for follow-up examinations.
What you can do yourself
The development of the tumor disease occurs in most cases in children. Therefore, relatives and especially parents are responsible for providing the best possible support to the patient in everyday life. Self-help measures focus on working closely and harmoniously with the treating medical team, as well as following their instructions. Studies repeatedly show that spiritual and mental stability is particularly important in coping with the disease. Therefore, conflicts and stressful situations should be avoided as much as possible. Activities to promote enjoyment of life and well-being are paramount. At the same time, the child should receive instruction and be supported as best as possible in the natural learning process. The child should be adequately informed about the present illness as well as its consequences. The occurrence of possible symptoms should be discussed with the child so that situations of anxiety or panic can be kept to a minimum. Since the disease is associated with numerous health restrictions and long-term therapy is required, the child must be emotionally prepared in good time for the further course of action. Contact with other children is important during this time and should therefore be encouraged. Sharing experiences together can be helpful in coping with the circumstances. Similarly, closeness to family members is tremendously important throughout the treatment period.
