Wilm’s tumor is a rare kidney malignancy that primarily affects children. This condition accounts for around 5% of all the diagnosed cancer in children. Although occurrence in the adult population have been reported, this event has been very rare [1, 2].
Anatomy and Pathophysiology
The kidneys are a pair of bean-shaped organs that are located in the back of the abdomen. The primary functions of the kidneys are to filter the blood of its waste, maintain the fluid balance of the body and regulate the amount of electrolytes in the blood. Each fist-sized kidney contain about 1 million functioning unit called nephron which serves as blood filter. Some kidney diseases does not get prompt treatment because it is possible to lose 90% of kidney function before any symptoms of kidney failure is seen [3].
Wilm’s tumor or nephroblastoma is considered to be the most common abdominal malignancy in children. This condition mostly affects children between the ages 3-4 and its occurrence decreases after the age of 5. Most of the time, only one kidney is affected, but there are instances where both kidneys of the child have the malignancy. Improvements in the diagnosis and management of this condition have improved the prognosis wherein around 80-90% of those who are diagnosed are able to survive [1, 2, 4]. Figure 1 shows an example of wilm’s tumor.
Figure 1- Wilm’s Tumor in the Kidney
Wilm’s Tumor Staging
A staging system has been developed by the Children’s Oncology Group (COG) in order to describe the Wilm’s tymor extent [1].
Stage I
The tumor was limited to one kidney and it has not affected nearby tissues and blood vessels [1].
Stage II
Tumor have grown beyond the kidney and have affected nearby fatty tissues and blood vessels but the nearby lymph nodes does not contain any cancer cells [1].
Stage III
Malignancy may have spread to the lymph nodes found in the pelvis and abdomen but more distant lymph nodes are not affected. It has already grown in to nearby organs and surgery will not be able to remove it completely [1].
Stage IV
Cancer cells have spread through the blood and affected distant organs such as the brain, liver, lungs and bones [1].
Stage V
Tumors are present in both of the kidneys during the time of diagnosis [1].
ICD10
Patients who have been diagnosed with wilm’s tumor are given the C64.9 ICD-10-CM diagnosis code. This is for the malignant neoplasm of the kidney [5].
Causes
Wilm’s tumor’s exact cause is still being studied but some of the things that are being considered are alterations in the genes that are responsible for the development of the genitourinary system. The alterations allow for the cells to grow uncontrollably. Some of the congenital anomalies associated with this condition are hypospadias, horseshoe kidneys and cryptorchidism. There are also instances where gene errors have been passed on from the parents to their children [2, 6].
Signs and Symptoms
Diagnosing wilm’s tumor in its early stage can be hard because the children who are affected appears healthy. Oftentimes, the first symptom that is noticed is a swelling or a hard mass that is felt into the abdomen. They are generally not painful but there are those who complain of some belly pain. Some of the children may also experience nausea, high blood pressure, loss of appetite, fever and presence of blood in their urine [1, 2, 7].
Diagnosis
Health history and physical examination
Children will be brought to the physician due to the discovery of the lump in their abdomen. Because there are several conditions which may cause this, it must also be correlated with other symptoms that are present in order to establish the diagnosis [2, 7].
Laboratory tests
The physician may request the use of imaging tests to help in establishing the diagnosis. These tests will be able to provide information about the size of tumor which will help the physician to identify its stage and the course of treatment that is necessary. Blood tests and urinalysis will be able to tell the functioning level of the kidney that is affected by the wilm’s tumor [7].
Treatment
Surgery
Surgery is usually the treatment of choice for wilm’s tumor. The procedure may involve removing a portion of the kidney if the tumor is small. If the tumor has damaged most of the kidney, the entire affected kidney may be removed and the remaining kidney will be able to filter the blood. In a stage V wilm’s tumor, both of the kidneys will have to be removed and the child may have to undergo renal dialysis for the rest of his/her life. A kidney transplant may be done to stop the need for dialysis [2, 7].
Chemotherapy
Chemotherapy uses drugs in order to eliminate the cancer cells. These drugs are administered either orally or intravenously. This method may be done to decrease the size of the tumor before removing it surgically and it may also be performed after a surgery in order to remove the cells that may be left behind. Although chemotherapeutic drugs have side effects, this regimen is utilized for the treatment of advanced types of wilm’s tumor [2, 7].
Radiation therapy
This mode of therapy uses high energy beams to eliminate cancer cells. These beams are produced by a machine that moves around the patient. Side effects associated with radiation therapy may include diarrhea, fatigue and skin irritation. Like chemotherapy, radiation therapy may either be done before or after the surgical procedure [2, 7].
Prognosis and Survival Rate
Identifying the stage of the Wilms tumor is essential in giving the prognosis of the patient. Patients who have an anaplastic Wilms tumor have a poorer outlook than those with a favorable histology. The 4-year survival are as follows:
Wilms Tumor Survival rate based on staging
- Stage I- 99%
- Stage II- 98%
- Stage III- 94%
- Stage IV- 86%
- Stage V- 87%
Anaplastic Wilms Tumor
- Stage I- 83%
- Stage II- 81%
- Stage III- 72%
- Stage IV- 38%
- Stage V- 55%
Other factors which can affect the prognosis are age of the patient at the time of the diagnosis and the response of the tumor to the treatment process.
References
- American Cancer Society. (2016, February 02). Wilms Tumor. Retrieved from American Cancer Society: http://www.cancer.org/cancer/wilmstumor/detailedguide/wilms-tumor-key-statistics
- Mayo Clinic Staff. (2014, November 6). Wilms Tumor. Retrieved from Mayo Clinic: http://www.mayoclinic.org/diseases-conditions/wilms-tumor/basics/definition/con-20043492
- Web MD. (2015). The Kidneys. Retrieved from Web MD: http://www.webmd.com/urinary-incontinence-oab/picture-of-the-kidneys
- Yeomanson, D. (2013, January 1). Wilms’ tumour in children. Retrieved from Macmillan Cancer Support: http://www.macmillan.org.uk/cancerinformation/cancertypes/childrenscancers/typesofchildrenscancers/wilmstumour.aspx
- ICD10 Data. (2015). Malignant neoplasm of unspecified kidney, except renal pelvis. Retrieved from ICD10 Data: http://www.icd10data.com/ICD10CM/Codes/C00-D49/C64-C68/C64-/C64.9
- Paulino, A. C. (2016, April 27). Wilm’s Tumor. Retrieved from Medscape: http://emedicine.medscape.com/article/989398-overview#a5
- Griffin, G. (2012, March). Wilms Tumor. Retrieved from Kid’s Health: http://kidshealth.org/en/parents/wilms.html#
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