Wilms’ tumour, or nephroblastoma, is a rare type of kidney cancer that generally affects children. It is a type of blastoma, which are cancers that develop from precursor cells in the body. It is generally found in only one kidney, however in rare instances in can be found in both kidneys.
The kidneys are a pair of bean-shaped organs that sit in the middle of your back on each side of your spine. They are responsible for filtering excess water and waste products from the blood, and converting them into urine to be removed from the body. The kidneys also produce and secrete certain hormones that regulate blood pressure and initiate the production of red blood cells.
Wilms’ tumours are slightly more common in girls, and are generally diagnosed in children under five years of age. However, anyone can develop this disease.
Treatment
If a Wilms’ tumour is detected, it will be staged and graded based on size, metastasis (whether the cancer has spread to other parts of the body) and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you.
Cancers can be staged using the TNM staging system:
- T (tumour) indicates the size and depth of the tumour.
- N (nodes) indicates whether the cancer has spread to nearby lymph nodes.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localised cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advanced or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including location, age, stage of disease and overall health.
Treatment options for Wilms’ tumour may include:
- Surgery, potentially including:
- Partial nephrectomy (partial removal of affected kidney(s)).
- Total nephrectomy (complete removal of affected kidney(s)).
- Chemotherapy.
- Radiation therapy.
- Immunotherapy.
- Targeted therapy.
- Clinical trials.
- Palliative care.
For more information on the treatment options, please refer to the Rare Cancers Australia treatment options page.
Risk factors
While the cause of Wilms’ tumour remains unknown, the following factors may increase the likelihood of developing the disease.
- Genetic mutations.
- Having certain conditions, such as:
- WAGR syndrome (Wilms’ tumour, aniridia, abnormal genitourinary system, and mental instability).
- Denys-Drash syndrome.
- Beckwith-Wiedemann syndrome.
- A family history of Wilms’ tumour.
- Aniridia.
- Isolated Hemihyperplasia.
- Hemihypertrophy.
- Urinary tract problems, potentially including:
- Cryptorchidism.
- Hypospadias.
- Exposure to pesticides in utero.
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Some of the information regarding risk factors was obtained from the Wilms Tumor and Other Childhood Kidney Tumors Treatment (PDQ) page published by the National Cancer Institute.
Early symptoms
Many children may appear asymptomatic in the early stages of disease. As the cancer progresses, some of the following symptoms may occur:
- An abdominal mass.
- Abdominal swelling and/or pain.
- Fever.
- Blood in urine.
- Nausea and/or vomiting.
- Constipation.
- Unexplained weight loss/loss of appetite.
- Shortness of breath.
- High blood pressure.
- Fatigue.
- Weakness.
- Anaemia.
Not everyone with the symptoms above will have cancer but see your general practitioner (GP) if you are concerned.
Diagnosis/diagnosing
If your doctor suspects you have a Wilms’ tumour, they will order a range of diagnostic tests to confirm the diagnosis, and refer you to a specialist for treatment.
Physical examination
Your doctor will collect your overall medical history, as well as your current symptoms. Following this, they may examine your body to check for any abnormalities.
Imaging tests
The doctor will take images of your body using magnetic resonance imaging (MRI), a computed tomography scan (CT scan), x-ray, and/or positron emission tomography (PET scan), depending on where it is suspected the cancer is. The doctor may also look at other parts of the body and looks for signs of metastasis.
Urine & blood tests
Urine and blood tests are used to assess overall health and detect any abnormalities. Some of these tests may include:
- General blood test to assess overall health.
- Full blood count, which measure the levels of red blood cells, white blood cells and platelets.
- Blood chemistry and/or blood hormone studies, which analyse the levels of certain hormones and other substances in the blood.
- Urinalysis, which analyses the colour of your urine and its contents (e.g., sugar, protein, red and/or white blood cells etc.).
Exploratory procedures & biopsy
You may require an exploratory procedure if you have blood in your urine, or if the imaging scans were inconclusive. Some of these procedures include a cystoscopy (an examination of the bladder), ureteroscopy (examination of the ureters) and ureterorenoscopy (examination of the kidneys). In all procedures, thin tube with a light and a camera is inserted through the genital tract to examine these areas and detect any abnormalities.
Once the location(s) of the cancer has been identified, the doctor will perform a biopsy to remove a section of tissue using a needle. The tissue sample will then be analysed for cancer cells. This can be done by a fine needle aspiration (FNA) or a core needle biopsy (CNB).
Prognosis (Certain factors affect the prognosis and treatment options)
While it is not possible to predict the exact course of the disease, your doctor may be able to give you a general idea based on the rate and depth of tumour growth, susceptibility to treatment, age, overall fitness, and medical history. Generally, early-stage Wilms’ tumours have a better prognosis and survival rates. However, if the cancer is advanced and has spread, the prognosis may not be as good and there may be a higher risk of cancer recurrence. It is very important to discuss your individual circumstances with your doctor to better understand your prognosis.
References
Some references are to overseas websites. There may be references to drugs and clinical trials that are not available here in Australia.