Kidneys are bean-shaped organs present on either side of the spine, below the ribs, behind the peritoneum, and are protected by the lower ribcage. Adrenal glands are small, endocrine glands that are present on top of each kidney. The kidneys and adrenal glands are surrounded by renal fascia, a fibrous tissue. Nephroblastoma is a type of kidney cancer, seen mostly in kids and rarely in adults. It is known as Wilms’ tumor after the doctor Max Wilms, who first identified it and wrote medical articles on it in 1899.
The symptoms of Wilms’ tumour may resemble other diseases, therefore, the condition must be diagnosed after intensive testing. The symptoms associated with Wilms’ tumor are:
- Abdominal swelling, pain, discomfort
- Increased and uneven growth on one side of the body
- Non-tender abdominal mass on palpation
- Abnormal coloration of the urine
- Loss of appetite
- High blood pressure
- Shortness of breath
The exact cause for nephroblastoma is unknown, but there are many risk factors for Wilms’ tumor. These factors are:
- Genetic factors- Certain genetic syndromes are associated with Wilms’ tumour.
- Race or ethnicity- African Americans are more prone to nephroblastoma than with Asian Americans.
- Gender- Girls are more prone to Wilms’ tumor than boys.
- Birth defects- Certain birth defects are associated with nephroblastoma, such as partial or complete missing of the iris in the eye, undescended testes, urinary opening at the underside of the penis etc.
Children suffering from birth defects and genetic factors should undergo diagnostic testing. The following tests may be ordered:
- Genetic studies
- Ultrasound of the abdomen
- Intravenous pyelogram
- Renal angiography
- Chest CT scan
- Kidney biopsy
- MRI scan
- Complete blood count test
- Urine analysis
The stages of nephroblastoma depend on the extent of the cancer growth are:
- Stage I: The cancer is completely confined to one kidney, and can be removed completely by the surgery. About 40 to 45% of Wilms’ tumors are diagnosed in stage I type tumors.
- Stage II: The cancer has spread to the tissues and blood vessels beyond the affected kidney and can still be completely removed by the surgery. About 20% of Wilms’ tumors are diagnosed in stage II type tumors.
- Stage III: The cancer has spread beyond the kidney area to the nearby lymph nodes and structures within the abdomen. The tumor may not be completely removed by surgery. About 20% of Wilms’ tumors are diagnosed in stage III.
- Stage IV: The cancer has spread to distant structures such as liver, lungs, brain, and bones. About 10% of Wilms’ tumors are diagnosed in stage IV.
- Stage V: Cancer cells are found in both the kidneys. About 5% of Wilms’ tumors are diagnosed in stage V.
Wilms’ tumor can be classified by histology testing (observing tumor cells under the microscope). There are two types:
- Unfavorable histology: About 10% of Wilms’ tumors show this type of histological features and are difficult to cure. The tumors have a nucleus in the cells that look very large and distorted. This is referred to as anaplasia.
- Favorable histology: About 90% 0f Wilms’ tumors show this type of histological features and are easy to cure. These tumors don’t have anaplasia.
The treatment for nephroblastoma is dependent on the stage of cancer and the type of histology it shows. The most useful and successful approach is nephrectomy followed by chemotherapy, with or without postoperative radiotherapy. This treatment is useful for children with Stage I and Stage II Wilms tumor.
Nephrectomy can be of three types depending on the level of spreading of the tumor cells of the kidney.
- If the kidney is completely removed, then it is known as radical nephrectomy. The other kidney can take the responsibility of functioning completely.
- If the kidney is partially removed, then it is called radical nephrectomy or partial nephrectomy.
- In some cases, both the kidneys have to be completely removed and the patient is put on dialysis till a kidney transplant is available.
Routine postoperative radiotherapy to the flank is beneficial for Stage III Wilms’ tumor. Patients with stage IV and stage V type of Wilms’ tumor should be considered for pre-operative chemotherapy because of the risk of initial surgical resection.
The complications associated with nephroblastoma and its treatments are:
- Increased risk of secondary tumors
- Hair loss
- Loss of appetite
- Low white blood cell count
About 90% of the children suffering from Wilms’ tumors can be treated successfully. The prognosis for children with unfavorable histology is worst than children with favorable histology.