Wilms tumor is a highly malignant neoplasm affecting the parenchyma of the kidneys. Develops in young children. It often proceeds asymptomatically and is detected during the next examination. When germinating into the cup system, macrohematuria occurs, when germinating into the surrounding tissues, pain syndrome occurs. Weakness, malaise, hyperthermia, increased blood pressure, nausea, vomiting and stool disorders may be detected. Wilms’ tumor is diagnosed on the basis of radiography, excretory urography, ultrasound, CT and MRI. Treatment – surgical interventions, chemotherapy, radiation therapy.
Meaning
Wilms’ tumor is an embryonic neoplasia of a high degree of malignancy. It is named after Max Williams, a German surgeon who at the end of the XIX century first described the process of histogenesis of this neoplasm, consisting of epithelial, stromal and embryonic cells. The tumor is the most malignant neoplasm of renal tissue in children, accounting for 20-25% of the total number of oncological kidney lesions in young patients.
It is usually diagnosed up to 5 years. It may be congenital. Girls and boys suffer equally often, the average age of boys at the time of detection of volume education is 3 years 5 months, girls – 3 years 11 months. In 4-5% of cases, it is bilateral in nature. It is extremely rare in adults, patients with Wilms tumor make up 0.9% of the total number of patients with kidney neoplasms. The treatment is carried out by specialists in the field of clinical oncourology and nephrology.
Causes
It has been established that Wilms’ tumor arises as a result of genetic mutations, but the cause of these mutations in most cases remains unknown. In 1-2% of patients, a hereditary predisposition is detected (there are cases of the disease in the family). The probability of developing a neoplasm increases with some malformations, including aniridia (underdevelopment or absence of the iris of the eye), hemihypertrophy (uneven development of different halves of the body), cryptorchidism and hypospadias.
This pathology is detected in some rare syndromes, for example, in Denis-Dresch syndrome (includes Wilms tumor, male pseudohermaphroditism and kidney function disorders), Wiedemann-Beckwith syndrome (includes tongue enlargement and internal organ defects), WAGR syndrome (includes Wilms neoplasia, mental retardation, lack of iris, malformations genital and urinary system) and Klippel-Trenone syndrome (includes large birthmarks and dilation of the subcutaneous veins of the lower extremities, thickening and elongation of the limbs).
Classification
In clinical practice, classification by stages is usually used:
- Stage 1 – neoplasm within the kidney. The renal vessels and the organ capsule are not involved. There are no metastases.
- Stage 2 – the tumor extends beyond the kidney, affecting the vessels and / or capsule of the organ. The mobility of the neoplasm remains, radical surgery is possible. There are no metastases.
- Stage 3 – neoplasia metastasizes to the lymph nodes or abdominal cavity.
- Stage 4 – metastatic cancer of the liver, lungs, bones, spinal cord or brain is detected.
- Stage 5 – the neoplasm is bilateral in nature.
There is also a classification created taking into account the histological features of the tumor. According to this classification, there are two categories of neoplasms – with favorable or unfavorable histological signs.
Wilms tumor symptoms
Clinical manifestations are determined by the age of the child, the stage of the process, the presence or absence of secondary foci in the lymph nodes and distant organs. In the initial stages, there is an asymptomatic course or erased symptoms: weakness, lethargy, loss of appetite, weight loss, a slight increase in temperature. In the analysis of peripheral blood, an increase in ESR and moderate anemia are determined.
Sufficiently large neoplasias are probed through the anterior abdominal wall. Possible asymmetry of the abdomen. With large neoplasms, intestinal obstruction phenomena may occur. There are breathing difficulties caused by compression of the chest organs. During palpation, a painless mobile (at stages 1 and 2) or stationary (at stages 3 and 4), dense, usually smooth node is determined. Less often, Wilms’ tumor has a bumpy surface.
Pain occurs when compression of nearby organs, germination of the liver, diaphragm and retroperitoneal tissue. Blood in the urine appears during the germination of the cup-pelvic system, is found in less than 30% of patients. Microhematuria is observed more often than macrohematuria. With the addition of infection and tumor necrosis, proteinuria and leukocyturia are detected in the urine analysis. More than half of the patients have an increase in blood pressure. With the appearance of distant metastases, the clinical picture is supplemented by a violation of the function of the affected organs.
Diagnostics
The diagnosis is made by oncourologists, taking into account clinical symptoms, laboratory and instrumental data. At the initial stage, isolated developmental anomalies and characteristic syndromes are considered as an additional indication of a possible Wilms tumor. A peripheral blood test, a general urine test, a blood test for cancer markers and functional renal tests are prescribed. Excretory urography is performed to assess the condition of the calyx-pelvic system. An overview chest X-ray is performed, which allows to detect mediastinal displacement, an increase in the level of the diaphragm and secondary foci in the lungs.
Patients are referred for ultrasound of the retroperitoneal space, ultrasound of the abdominal cavity, CT of the retroperitoneal space, CT of the kidneys, MRI of the kidneys and other studies. If vena cava is suspected, venography is used. To exclude bone metastases, skeletal bone scintigraphy and sternal puncture are prescribed, followed by microscopic examination of the punctate. To exclude damage to the central nervous system, CT and MRI of the brain and spinal cord are performed. Pathology is differentiated with polycystic fibrosis, hydronephrosis, kidney cyst, renal vein thrombosis and other kidney tumors.
Treatment
The treatment is combined, including surgery, chemotherapy and radiotherapy. Depending on the degree of organ damage, partial or total nephrectomy is possible. Patients under the age of one year are operated on without prior chemotherapy. Children older than 1 year are prescribed preoperative chemotherapy for 1-2 months. During the surgical intervention, both kidneys are audited. With bilateral neoplasms, bilateral partial nephrectomy or complete nephrectomy is performed on the one hand and partial on the other.
With extensive lesions of both kidneys, a complete bilateral nephrectomy was previously performed. Currently, preference is usually given to organ-preserving operations in combination with preoperative polychemotherapy, postoperative chemo- and radiotherapy. The paraaortic and mesenteric lymph nodes are excised. Histological examination of tumor tissue and lymph nodes is performed to clarify the diagnosis and more accurately assess the prevalence of the process. In case of inoperable neoplasms, palliative treatment is prescribed: chemotherapy, radiation therapy, symptomatic therapy.
Patients after a complete bilateral nephrectomy are referred for hemodialysis and put on the waiting list for a kidney transplant. Treatment of relapses is combined, including surgical interventions, radiotherapy and chemotherapy. During anti-relapse therapy, more aggressive chemotherapy drugs are used, which have a negative effect on the hematopoiesis system, therefore, in the future, patients may need bone marrow transplantation.
Prognosis and prevention
The prognosis for Wilms tumor is determined by the stage and histological features of the neoplasm. The five–year survival rate of patients with Wilms tumor of the first stage is 80-90%, the second – 70-80%, the third – 35-50%, the fourth – less than 20%. Relapses of the primary neoplasm are detected in 5-15% of patients. The two-year survival rate in the presence of relapse is about 40%. Unfavorable prognostic factors are certain histological features of Wilms’ tumor, the age of the patient younger than 1.5 years or older than 5 years, interruption of the course of radiation therapy or chemotherapy.
After the end of the treatment cycle, patients with Wilms tumor undergo monthly ultrasound of the abdominal cavity and retroperitoneal space for 2 years, take blood and urine tests. Then the examination is carried out every three months. Chest X-ray is performed twice with a three-month interval, then carried out every six months. In the long-term period, the development of metastases and malignant neoplasms provoked by radiation therapy is possible. Women have an increased risk of antenatal fetal death and the birth of a low-weight baby.