Nephroblastoma: Causes, Symptoms, Risk factors, Treatments and Prevention
Nephroblastoma (a.k.a: Wilms tumor) is a rare type of kidney cancer that affects the children. It is seen in children in the age group of 3 – 4 years. Mostly, this type of cancer affects only one kidney. However, in some cases both the kidneys are affected.
Early detection and proper treatment help to decrease the severity of the disease and survival of the patient.
- What are the Causes of Nephroblastoma?
- What are the Symptoms of Nephroblastoma?
- What are the Risk Factors for Nephroblastoma?
- What are the Complications of Nephroblastoma?
- How is Nephroblastoma Diagnosed?
- How is Nephroblastoma Treated?
- How is Nephroblastoma Prevented?
What are the Causes of Nephroblastoma?
The exact cause of nephroblastoma is still not clear. However, research studies showed that during the initial stages of fetal development the early kidney cells develops in to mature kidney cells. As a result of mutation occurring in the genes (genes that control the development of kidney cells), there is delay in the maturation of kidney cells. Therefore, some of the early kidney cells remain in the body after the child birth. These cells would mature within 3 to 4 years. But in some cases, these cells don’t mature and begin to grow uncontrollably forming a tumor called Wilms tumor.
What are the Symptoms of Nephroblastoma?
The patient does not show any symptoms in early stages of nephroblastoma until the tumor becomes large and spreads to other body parts. However, in some cases the following signs and symptoms are seen:
- Abdominal swelling
- Urine discoloration
- Blood in urine
- Pain in abdomen
- Felling unwell
- Unintentional weight loss
- Distended veins in abdominal region
What are the Risk Factors for Nephroblastoma?
The following factors increase the risk of nephroblastoma:
1. Genetic Factors:
The risk of nephroblastoma increases if the patient is already having any of the following genetic syndromes:
- Beckwith-Wiedemann syndrome
- Bloom syndrome
- Denys-Drash syndrome
- Frasier syndrome
- Li-Fraumeni syndrome
- Perlman syndrome
- Simpson-Golabi-Behmel syndrome
- Sotos syndrome
- Trisomy 18, also called Edward’s Syndrome
- WAGR syndrome
The above mentioned syndromes are caused due to various genetic mutations at different stages of development.
2. Birth Defects:
The risk of nephroblastoma is high in patients having any of the following birth defects:
- Aniridia: In this condition a part of eye called iris is absent
- Hemihypertrophy: The person affected with this condition has uneven body; one side of the body is larger than the other side
- Cryptorchidism: The testicles are undescended into the scrotal sacs after the childbirth
- Hypospadias: The urinary opening is present underside of the penis
The occurrence of Wilms tumor is more in African-American children when compared with whites. It occurs rarely in Asian-American children.
The risk of Wilms tumor is more in females than in males.
What are the Complications of Nephroblastoma?
The following are the common complications of nephroblastoma:
- Metastasis, the Wilms tumor would spread to other parts of the body just like any other cancer.
- High blood pressure
- Kidney failure
How is Nephroblastoma Diagnosed?
The diagnosis of nephroblastoma is made by the following approaches:
- Physical examination: The doctor physically examines the patient for the signs and symptoms and obtains the child’s family and medical history. The mother’s pregnancy details are also obtained.
- Blood tests: The doctor recommends blood tests to determine the functioning of kidneys and liver.
- Urine tests: The patient’s urine sample is collected and tested for sugar, bacteria, blood and proteins.
- Abdominal ultrasound scan: This test uses sound waves to view organs and structures in the abdominal region. This is a non-invasive technique and works with sound waves to create the clear images of kidneys and other veins in the abdomen.
- Magnetic resonance imaging (MRI): An MRI uses powerful radio waves and magnetic fields to obtain a detailed image of the organs present in abdominal region. In this test, a dye is injected into the patient’s veins.
- Computerized tomography (CT) scan: In this procedure, the doctor would give a contrast substance by mouth or through an intravenous line to facilitate the clear examination of the kidneys. A CT scan uses X-rays to obtain a detailed image of kidneys.
- Biopsy: A sample of kidney tissue is collected from the patient and is sent to a laboratory for microscopic evaluation. The pathologist examines the tissue microscopically and determines the presence of tumor.
- Chest X-ray: The doctor would recommend chest X-ray to determine if tumor has spread to lungs.
How is Nephroblastoma Treated?
A team of surgeons, pediatricians, urinary tract specialists and cancer specialists would plan the patient specific treatment. General treatment options include:
Simple nephrectomy: The surgeon would consider treating the patient by surgically removing one kidney.
Partial nephrectomy: In this procedure, the tumor along with the surrounding kidney tissue is surgically removed. The doctor would recommend this procedure if the patient has only one kidney or if one of the two kidneys is unhealthy.
Radical nephrectomy: The surgeon would remove whole kidney, adrenal gland and lymph nodes and other surrounding tissues. As a part of surgery the patient’s abdominal cavity is examined and certain tissue samples are collected for further evaluation.
Chemotherapy includes treating the patient with oral or intravenous anti-cancer drugs. The patient is given a single drug or combination drugs for few weeks to months. After administration, these drugs act on the cancer cells to kill them. These drugs also act on normal body cells and causes following side-effects:
- Loss of appetite
- Hair loss
However, these side effects would disappear after the completion of chemotherapy.
This therapy uses high energy beams to destroy the cancer cells. The table is provided for the patient to rest and radiation is applied to the targeted regions to destroy cancer cells. The frequency and duration of the radiation therapy is adjusted as per the patient’s severity of cancer.
As the patient’s abdominal area is targeted, the patient would experience diarrhea. Other possible side effects include mild skin reaction, stomach upset, and fatigue.
The doctor would replace the affected kidney with the healthy kidney obtained from donor. The replaced kidney starts to produce urine within few days.
How is Nephroblastoma Prevented?
The prevention of nephroblastoma is not possible. But an early detection and appropriate management of the disease helps in early recovery of the patient.
There is a high risk of developing nephroblastoma in children with certain genetic syndromes and birth defects. This risk can be decreased by screening the children regularly with ultrasound to determine kidney abnormalities. However, screening does not prevent Wilms disease but help in early identification of the disease.