General Information about the Wilms' Tumor
The number of cases of cancer among the world’s population is frightening, and what is even worse, oncological diseases also affect children. Retroperitoneal tumors are one of the most common ones in infants, and sometimes, they can begin to develop during the formation of the baby before birth. Many researchers attribute this to air pollution, poor diet, and the low level of development of the country which increases the stress experienced by individuals.
Pediatric oncology is a relatively young science, which began to develop rapidly only a few decades ago. Renal oncology, in particular, started to draw the interest from some scholars in the 19th century with Max Wilms being one of those scientists (American Cancer Society, 2015). He was the first one who conducted studies of kidney disease in children, namely nephroblastoma or kidney cancer. As a result, in 1899, he published a review of the literature describing this type of cancer (American Cancer Society, 2015). At the time, it was a relatively rare phenomenon, which explains the lack of interest to it among researchers and physicians. Today, Wilms’ tumor is one of the most common malignant kidney tumors in children. Despite the high cure rates, it is very dangerous for kids, especially in the latter stages of its development. Thus, it is necessary to take both practical and theoretical measures to fight it. This paper describes the symptoms of Wilms’ tumor, its clinical condition, causes, treatment, and consequences.
Wilms’ tumor, or nephroblastoma, is a malignant tumor that develops in the kidney (Faranoush, Mehrvar, Asl, & Ghorbani, 2009). According to various sources, this disease is one of the most common neoplasms of the retroperitoneal space (Faranoush, Mehrvar, Asl, & Ghorbani, 2009). German surgeon Max Wilms revealed the disease in the child, and later, found that nephroblastoma could occur only in children aged 3-4 as their kidney tissue has a large number of embryonic cells (American Cancer Society, 2015). The frequency rate of this kind of cancer is the same for both boys and girls (American Cancer Society, 2015). In addition, nephroblastoma can influence one kidney or two at a time that is called a bilateral multifocal neoplastic process and can be observed more often in girls than among boys (American Cancer Society, 2015). Adults and adolescents suffer from this disease extremely rarely. Children with congenital malformations that are caused by genetic mutations are at increased risk of the disease.
The Causes of the Disease
Speaking about the causes of the disease, it must be said that the exact reasons are unknown. The world’s best experts in the field of medicine, embryology, and genetics have been involved in the research process for several years, but the findings do not give an accurate answer (American Cancer Society, 2015). It has only been proved that radiation and carcinogens increase the risk of the disease.
One should start by stating that Wilms’ tumor begins to form due to severe mutations in the genetic apparatus of cells. Thus, some scientists suggest that susceptibility to the disease is transmitted by the inheritance of DNA (Sandstedt, & Vujanic, 2016). However, the direct link between heredity and the occurrence of the tumor has not been established so far. In fact, cases of family nephroblastoma transmitted by inheritance from parents to an offspring are extremely rare and account for not more than 1.5% (Sandstedt & Vujanic, 2016). Speaking about the relationship between Wilms’ tumor and congenital anomalies, it is necessary to highlight that the most wide-spread ones that accompany the disease are aniridia and cryptorchidism. In addition, the high-risk group includes children with sporadic aniridia combined with chromosomal abnormalities. At the same time, congenital anomalies, such as hemihypertrophy, hypospadias, as well as the presence of two renal pelves of each kidney, increase the risk of cancer (Ko, 2008).
Some researchers also stress the link of Wilms’ tumor with the presence of abnormalities of the child’s musculoskeletal system and anomalies of the urinary system. It is also necessary to mention the relation of nephroblastoma with some rare syndromes such as Beckwith-Wiedemann syndrome (increased body weight and visceral), WAGR (combines several symptoms of abnormal development), Denys-Drash syndrome (underdevelopment of genitals), Klippel-Trenaunay syndrome, and congenital nephroma (i.e. kidney tumor in infants) (Dome, Graf, & Geller, 2015).
The Detection and Symptoms of the Disease
The early stages of nephroblastoma are not characterized by palpable signs. In rare cases, the disease manifests itself through malaise, weakness, and fever. Therefore, Wilms’ tumor is an insidious disease as in the initial phases of its development, it is asymptomatic and quiet, without causing the slightest suffering of the child. Even with rather large tumors, the child continues to look healthy.
Typically, the neoplasm is detected by parents while bathing or during the scheduled examinations by a pediatrician (Sandstedt & Vujanic, 2016). By the time it is discovered, the tumor can be quite large and is usually in the form of a tight painless lump with a smooth or rough surface in the baby’s tummy. At the early stages, it is characterized by homogeneity and has sharp contours and boundaries. During palpation, one does not feel pain. However, the later phases of the neoplasm growth demonstrate a sharp enlargement of the abdomen and a violation of its symmetry as the tumor becomes inhomogeneous and begins to compress the adjacent organs such as the liver, uterus, stomach, and so on.
To continue, the mobility of the tumor depends on its size while its growth rate is often related to the age of a child with the neoplasm developing faster if the kid is older (Dome, Graf, & Geller, 2015). In this case, the tumor may go down into the pelvis or climb up to the diaphragm and affect the spleen (Dome, Graf, & Geller, 2015). Furthermore, it may have an impact on the thorax which expands under the influence of nephroblastoma (Dome, Graf, & Geller, 2015). In addition, Wilms’ tumor can stretch the skin of the abdomen to the groin causing the expansion of the vascular network in the subcutaneous tissue (Dome, Graf, & Geller, 2015). This, in turn, can cause an accumulation of fluid in the abdomen, and the development of ascites (Dome, Graf, & Geller, 2015). At this stage of the disease, the child begins to feel pain in the abdomen, but it is extremely difficult to determine its exact location. The mobility of the tumor can cause increased blood pressure and leukocyturia, hematuria, proteinuria. However, pain in the early and middle stages of nephroblastoma is a rare phenomenon, and usually, kids feel healthy and active. This is due to the spread of cancer into the other organs without having the negative damaging effect on them (American Cancer Society, 2015). The painful feelings can be explained by the compression of sensitive nerve endings of such body parts as the diaphragm, liver, and retroperitoneal fat. Additionally, significant stretching of the fibrous renal capsule can cause pain as well.
If the tumor begins to germinate in the pelvis or capsule, it could cause hematuria in the middle and late stages of the disease which is a clear sign of Wilms’ tumor when experienced by a child of 2-5 years old(Ko, 2008). In most cases, hematuria is the result of urine diversion malfunction which, in turn, can be provoked by a lowering of the pelvis tumor (Ko, 2008). Hemodynamic disturbances in the kidneys lead to the destruction of internal membranes of the glomerular capsule (Ko, 2008). As the circulatory system of the kidneys is connected to the pelvis, one can observe the bleeding with urinary excretion (Ko, 2008). At the same time, symptoms such as a monocytosis, lymphocytosis, increased ESR may indicate the severity of the tumor, and the presence of metastases (Ko, 2008).
The vast number of children suffering from nephroblastoma may also have systemic symptoms. These include the general weakness of the body, sudden weight, and appetite loss. Since the tumor can affect the stomach, digestive problems can also occur (Segers, 2013). Another sign of the disease can be constipation since it may be caused by the compression of the intestine due to the overgrown tissue of neoplasm (Segers, 2013). Furthermore, frequent nausea also refers to the symptoms and is a result of a violation of the digestive tract (Segers, 2013). Another sign that one can name is reduced physical activity that is provoked by the disruption of blood flow due to the unstable operation of the liver (Segers, 2013). Loss of potassium as well as a number of other useful elements not only causes muscle weakness but also decreases the child’s emotional activity (Segers, 2013). Lastly, if there are metastases present in the lungs, the baby may suffer from a dry cough (Segers, 2013).
Diagnosis of the Wilms’ Tumor
Various imaging techniques are used to verify the diagnosis of the disease under consideration. In the early stages of the Wilms’ Tumor, ultrasound examination of the abdominal cavity and retroperitoneal space, and intravenous urography are necessary and the most reliable methods to discover the nephroblastoma. Ultrasound is non-invasive and is essential for the differential diagnosis of Wilms’ Tumor (Ko, 2008). With its help, a doctor can notice the circular formation of increased echogenicity located in the retroperitoneal space (Sandstedt & Vujanic, 2016). Its early disclosure is really vital as this will reduce the risk of the enlargement of the neoplasm and minimize its effect on the kidneys, liver, and other organs. Additionally, diagnosis using ultrasound allows doctors to prescribe treatment in time, and consequently, patients often avoid surgery or radiation therapy. The approach also makes it possible to determine the size of the tumor, its location, and even the presence and location of metastases. In order to detect distant metastasis, doctors can use ultrasound of the chest as well as bone scintigraphy (Segers, 2013). Ultrasonography is also applied during the biopsy for histological examination that allows doctors to detect abnormal cells in the child’s body. In addition to the above stated, it is indispensable during the observation of the patient after the completion of the treatment program.
However, CT scan or ultrasound may not provide enough information for nephroblastoma to be diagnosed accurately as there are some diseases that are very similar to Wilms’ Tumor, e.g., neuroblastoma. In this case, additional research has to be conducted by doctors. For example, to determine nephroblastoma and distinguish it from neuroblastoma, specialists can use the scintigraphy method, which is the introduction of radioactive isotopes in the body to produce an image of the tumor (Sandstedt & Vujanic, 2016). This method is rarely used, but it is indispensable in some cases.
In recent years, computed tomography of the abdomen has been widely used in the diagnosis of Wilms’ tumor. This method is based on the principle of imaging neoplasms and consists of the layered transverse scanning of nephroblastoma with the narrow X-ray beam (Sandstedt & Vujanic, 2016). Processing of the information obtained from the X-ray computer tomography sensors is done using a computer (Sandstedt & Vujanic, 2016). The result appears on the screen in the form of three-dimensional images of the kidneys, the nearest vessels, and other organs, providing the doctor with comprehensive information on the nature of nephroblastoma and its stage (Sandstedt & Vujanic, 2016).
The Treatment of the Disease
Wilms’ tumor treatment method depends on the stage of the disease and the morphological structure of the tumor. When choosing a treatment strategy, doctors must take into account the patient’s age, individual characteristics of the organism and its state (Pritchard-Jones et al., 2012). The treatment of any disease should always be individualized, and nephroblastoma requires special care in the selection of appropriate therapeutic measures. At the same time, in virtually every case, various methods of treatment are combined and often include both surgery and chemotherapy. If the neoplasm is detected at an early stage, the prognosis is favorable in 80% of the cases (Dome, Graf, & Geller, 2015). It is worth noting that neuroblastoma is one of the few diseases that are highly amenable to surgical treatment. According to different statistical studies, the number of cured children with Wilms’ tumor is 90% (Ko, 2008).
In fact, the main method of treatment of neuroblastoma is surgery. The number of operations conducted depends on the size of tumors and their spread. In the early stages, the removal of the neoplasm can be enough; however, nephrectomy with regional lymph node dissection is used in the later phases of the disease (Pritchard-Jones et al., 2012). Naturally, surgical intervention should be applied as soon as possible after the detection of tumors. If such an abnormality is present in a newborn, it is to be operated during the first 14 days of his/her life (Pritchard-Jones et al., 2012). Wilms’ tumor which has reached the third or fourth stage and left the boundaries of the affected kidney requires a fundamentally different treatment since adjacent organs are at risk of damage while its removal (Faranoush, Mehrvar, Asl, & Ghorbani, 2009). Moreover, nephroblastoma of the last stage leads to the defeat of both kidneys. Surgical intervention at this stage is to remove part of the tumor tissue.
Nephroblastoma of the last stage leads to the defeat of both kidneys. As a result, tactics of surgical intervention at this stage may be different. In some cases, only the tumor and some lymph nodes are removed (Ko, 2008). In others, a kidney is cut out. This surgery is called a nephrectomy. It can be complete if the entire kidney is removed, a partial in case only a part of it is removed, and a radical one in which doctors remove not only the kidney but also the surrounding tissue (Pritchard-Jones et al., 2012). In the last-mentioned case, doctors prescribe patient dialysis sessions. After this, the patient needs urgent transplantation of a healthy organ. During treatment, it is necessary to monitor the state of the blood constantly as the therapy may cause a decrease in white blood cells and platelets in the blood.
After the operation, there are sessions of radiation and chemical therapy. Typically, doctors only irradiate the tumor region, but not the entire body. If the tumor remnants are noticed after surgery, these places are also subjected to irradiation.
There are cases when the tumor is broken during operation. In such a situation, the whole abdominal cavity should be irradiated in order to minimize the risks of relapse. If a child continues to suffer from metastasis even after preoperative chemotherapy and removal of the tumor, the doctor carries out the irradiation of the chest cavity (American Cancer Society, 2015).
Chemotherapy depends on such parameters as the stage of the disease, age of the child, as well as an overall health state. Doctors use drugs such as vincristine, dactinomycin, doxorubicin, and cyclophosphamide (Faranoush, Mehrvar, Asl, & Ghorbani, 2009). In radiation teletherapy, irradiation is recommended only in the middle and late phases of the disease (stage 3-4) (Faranoush, Mehrvar, Asl, & Ghorbani, 2009). In addition, doctors use palliative radiation directed at other nearby organs such as lungs and liver if they have been exposed to tumor invasion and metastasis (Faranoush, Mehrvar, Asl, & Ghorbani, 2009). The aim of these treatments is to prevent the recurrence of the disease or reduce the size of the tumor before surgery.
It should be noted that in recent years, research in the field of pharmaceuticals has brought tangible results that impact on the fight against Wilms’ tumor. Thus, new combinations of cytostatic medicines have emerged that make it not necessary to use radiation therapy in many cases. Preoperative chemotherapy using such drugs not only minimizes the harmful effects of the tumor but also inhibits the development of metastases in the body. However, some children are still forced to undergo radiation therapy if the form of the disease is really severe and the use of cytotoxic agents does not lead to tangible results.
In general, the forecasts for the treatment of disease are optimistic. Nephroblastoma is one of the few types of cancer which has the most appropriate and efficient treatment schemes (Sandstedt & Vujanic, 2016). The chances of recovery from nephroblastoma equal to approximately 90% if the disease has been discovered in the early stages. However, the child will have to undergo a full medical examination every year after the treatment, and also observe a strict diet which minimizes the load on the kidneys.
Summing up, Wilms’ tumor is malignant cancer that develops in the kidneys. As the disease develops very early in life, it is considered the nursery one. Symptoms of the disease include the presence of the formation (tumor) in the groin area, hematuria, general weakness of the body and weight loss. At the same time, often, children that have nephroblastoma do not show any particular signs of the disease. However, it is easy to diagnose it by ultrasonic method or computerized tomography. The development and proliferation of the tumor may affect other organs (liver, lungs, stomach, and uterus). Nephroblastoma metastases develop mainly in the lungs. Treatment of the disease includes both surgery and chemotherapy, and radiation exposure. Thanks to recent advances in the field of pharmacology, it has become possible to abandon radiotherapy replacing it with the use of new cytostatics. In most cases, children get cured which is due to timely diagnosis and effective treatment. If the disease has been diagnosed in the third or fourth stage, it will be quite difficult to fight it; however, the chance of recovery is present even in such a case.