Wilms tumor, or nephroblastoma, is a malignant and very aggressive kidney tumor that occurs primarily in small children. This disease was first described by surgeon Max Wilms, hence the name of the disease.
Wilms tumor is the most common type of kidney cancer in children, accounting for up to 90% of all childhood malignant lesions of kidney tissue. Every year in the United States, 500-600 new cases of nephroblastoma are registered. Approximately 75% of patients are under 5 years of age at the time of diagnosis.
Wilms tumor develops from mutated embryonic kidney tissue. Most often, tumor conglomerate contains kidney precursor cells, but it may also contain other tissues (connective, muscle, cartilage, epithelial, which are at different stages of differentiation). As a rule, tumor affects only one kidney, but there are cases of bilateral damage, as well as multiple (several nephroblastomas in one kidney).
Important! Wilms tumor grows rapidly and metastasizes relatively early. At the time of diagnosis, approximately 15% of children already have distant metastatic lesions of other organs. Most often, metastases are found in retroperitoneal lymph nodes, lungs, and less often in liver, brain, and bones.
Wilms tumor is a serious disease with a serious prognosis, but with timely diagnosis and proper complex therapy, it is completely curable. It is very important to find a specialist who has practical experience in managing patients with nephroblastoma and will help to develop a modern and effective treatment regimen. These are the doctors who work in Pediatric Oncology Department of Tel Aviv Medical Clinic. The approach to each sick child is individual. Developing a treatment plan, specialist does not use one template for everyone, but takes into account all patient’s characteristics and his disease. Thanks to this personalized approach, we are able to achieve success even in the most difficult situations.
Wilms tumor causes
Unfortunately, a single cause for Wilms tumor development in children has not been established to date, but research in this area has shown a connection between certain types of mutations on the 11th pair of chromosomes and the incidence of nephroblastoma. The so-called Wilms tumor gene 1 (WT1 gene) has been identified, which is normally responsible for the proper development of kidneys, and if there are mutations in it, the development of congenital kidney defects or nephroblastoma can be observed.
There has also been a connection between the presence of certain hereditary diseases or syndromes and Wilms tumor. Specialists in the field of genetics call such pathologies hereditary tumor syndromes, since such patients have a much higher risk of developing many malignant and benign tumors. Examples of hereditary genetic syndromes associated with the development of nephroblastoma:
- WAGR syndrome,
- Beckwith-Wiedemann syndrome,
- Hemihypertrophy,
- Denis Drash syndrome,
- Perlman syndrome other even rarer genetic syndromes.
Important! Children who are prone to nephroblastoma developing (have a mutation in the WT1 gene or one of the hereditary tumor syndromes, or have similar cases in family) are subject to regular screening examinations for the purpose of early tumor detection.
Nephroblastoma symptoms
As a rule, children with nephroblastoma do not worry about anything for a long time. Often the first symptom that parents notice is an increase in size of abdomen. Next, the child is taken for examination to a pediatrician, who, upon palpation, detects a tumor in abdomen. At the same time, child does not complain about anything.
In some situations, the first symptoms of Wilms tumor may be:
- abdominal pain,
- blood in urine
- back and lower back pain,
- temperature increase,
- indigestion and stool disorders,
- weight loss,
- increased blood pressure.
Modern diagnostic methods
In Pediatric Oncology Department of TAMC, the entire diagnostic process consists of 3 main stages and takes from 3 to 5 working days.
At the first stage, patient, together with his parents or custodians, is consulted by the leading specialist of the department. Doctor asks in details the parents and the child himself about complaints, collects an anamnesis of disease development, a hereditary history, which allows him to understand what kind of diagnosis he is dealing with this time. Next, the oncologist develops a plan for further examination, from which the second stage of diagnosis begins.
Diagnostics must include modern medical imaging techniques. First of all, this is necessary to confirm the diagnosis, as well as to determine tumor size, its spread and stage of nephroblastoma. For this purpose, CT, MSCT, MRI, and ultrasound are used.
Unfortunately, modern medical imaging techniques are sometimes insufficient to establish nephroblastoma diagnosis. In such situations, additional techniques are used, for example, MIBG scintigraphy with the introduction of radioactive iodine 123-I (MIBG). This radioisotope scan helps to distinguish between neuroblastoma and nephroblastoma in children.
If, with the help of modern diagnostic equipment and completed examinations, doctor is confident in diagnosis, then a tumor biopsy is performed only after a preoperative course of chemotherapy and surgical treatment. Tissue samples are taken during surgery to remove the tumor. Only in complex diagnostic cases can a biopsy be performed before starting complex treatment using puncture percutaneous kidney biopsy. After biopsy, we send all materials to the best pathohistological laboratories in Israel, where they are examined by a specialist pathologist for nephroblastomas diagnosis. Thanks to such thorough checks, we are confident that the diagnosis is correct and comprehensive treatment program is appropriate.
Prognosis for nephroblastoma
The prognosis for nephroblastoma depends on following factors: the histological variant of tumor (favorable and anaplastic), the stage of the disease at the time of diagnosis, and patient’s age.
Typically, the prognosis for children with Wilms tumor is favorable. In 85% of cases, neoplasm is detected in early localized stages. In such cases, radical treatment (surgical tumor removal) is used.
In some cases, nephroblastoma may recur after radical treatment. In such situations, the response to re-treatment is also good if relapse is detected in early stages.
Stages of nephroblastoma development:
- Stage 1 (20% of all primary diagnosis cases). The tumor is limited to kidney tissue and does not extend beyond it. There is the possibility of its complete surgical removal.
- Stage 2 (22% of all primary diagnosis cases). The tumor grows into kidney capsule and extends beyond its boundaries, but does not metastasize. There is also complete surgical removal possibility.
- Stage 3 (32% of all primary diagnosis cases). The tumor extends beyond kidney, but is located inside abdominal cavity. There is no possibility of complete surgical tumor removal.
- Stage 4 (20% of all primary diagnosis cases). The tumor metastasizes to distant organs and tissues (liver, bones, brain, lungs).
- Stage 5 (6% of all cases of primary diagnosis). Bilateral kidney damage by nephroblastoma.
Based on these 3 criteria, doctors at Pediatric Oncology Department of TAMC identify a risk group (low, medium and high) and develop an individual plan and treatment regimen that will ideally help a particular child and be the most effective for him.
Modern treatment of Wilms tumor
Children with Wilms’ tumor should only be treated by doctors from clinics that have a specialized Pediatric Oncology Department. Tel Aviv Medical Clinic is just such a medical institution. We employ highly qualified doctors specializing in Pediatric Oncology who are proficient in modern comprehensive treatment programs. The goal of any therapy program is to treat the child as sparingly as possible and at the same time reduce the risks of possible side complications during complex therapy and long-term consequences after its completion.
In treatment of children with nephroblastoma, oncologists primarily combine methods such as surgery and polychemotherapy. In rare cases, children receive an additional course of radiation.
As a rule, nephroblastoma treatment, begins with preoperative chemotherapy. This course helps to reduce the tumor in size and subsequently carry out radical surgery. Various chemotherapy regimens are used, which consist of the following cytostatic drugs: vincristine, actinomycin D, doxorubicin, etoposide, carboplatin. The duration of preoperative chemotherapy depends on disease stage.
The next treatment stage is surgery. The purpose of surgery is to completely remove the tumor tissue and obtain biological material for pathohistological and molecular genetic analysis. What type of surgical intervention will be performed on the child depends on whether the nephroblastoma is in one kidney or whether there is a bilateral lesion.
If tumor has affected only one organ of a pair, surgeons perform a nephrectomy – kidney removal along with tumor. Subsequently, remaining organ takes over all functions and the child grows and develops normally. In case of bilateral damage, doctors council chooses a surgical tactic that will allow to save at least one kidney for the child, that is, it can be a combination of organ-preserving interventions (partial kidney resection) on two kidneys or nephrectomy on one side and an organ-preserving procedure on the second.
Important! At TAMC Medical Center, minimally invasive surgical techniques are used whenever possible, and they also effectively practice robotic surgery in Wilms tumor treatment, which allows to reduce the extent of injured tissue, avoid the risk of postoperative complications and shorten the recovery period after surgery.
After surgery, young patients may be prescribed a course of postoperative therapy when the risk of tumor recurrence is high. A repeated course is usually long and can take from 6 months to 1 year.
The majority of children after radical treatment of nephroblastoma in combination with polychemotherapy do not require radiation therapy application. Radiation can be prescribed in complex treatment of children with a high risk of disease (stage 3 disease and above).
In each individual clinical case, the decision on a combination of certain treatment methods is made jointly by a team of specialists. Thanks to this approach, we are able to achieve a high level of patient survival, even in presence of metastatic disease. To treat nephroblastoma, highly specialized specialists are involved, closely interacting with each other. Constant communication allows us to make decisions quickly on adjusting treatment regimen, if necessary, and monitor the results of surgery and health status of little patient.
