Diagnosis of Wilm’s Tumor

The diagnosis of Wilm’s Tumor is often a surprise. A majority of children show few signs or symptoms prior to diagnosis.

The diagnosis of Wilm’s Tumor occurs in several stages.

The exam: The child’s pediatrician will preform a physical exam. The exam will focus on the abdominal area. Additionally, the provider will assess the child for high blood pressure (a possible sign of the disease), as well as take a thorough healthy history. If the provider finds signs that suggest Wilm’s Tumor, evaluation will continue on to the next step. 

Laboratory Tests: The most common lab tests ordered are blood and urine evaluations. Urine is primarily tested for blood, which is an indicator of kidney issues. Although there is no specific blood test for Wilm’s Tumor, blood tests are useful in that they evaluate the general health of a child’s kidneys, as well as body system as a whole.

Ultrasound Image of Wilm's Tumor 

Diagnostic Imaging: In addition to lab tests, the provider will order several different types of imaging tests. The first imaging test the patient will receive is an ultrasound. Ultrasounds use sound waves to create images of the structures inside the abdomen. Other imaging tests may also be ordered by the provider in order to gain a more detailed view of the kidneys, as well as surrounding areas. The two most common additional tests are CT scans and MRIs. A CT uses radiation to obtain a detailed view of the abdomen. An MRI uses magnets to create a similar, but more detailed picture of the affected area. Sometimes, special dye (known as contrast) is ingested or injected prior to both procedures to give additional detail to the scans. An expert will then interpret the images taken. Based on the findings, the next step is to confirm the diagnosis with surgery.

CT of Wilm's Tumor 

MRI of Wilm's Tumor 

Surgery: In the final stage of diagnosis, a surgeon will remove the entire affected kidney. Following removal of both the kidney and the tumor, a biopsy form the tumor is obtained. A biopsy is a small portion of the tumor taken to be analyzed in a lab. A pathologist (a doctor who specializes in looking at abnormal cells under a microscope) examines the sample, and makes the official diagnosis. 

Using data gathered from the four diagnosis steps, the medical team will stage the tumor (stage I, II, III, or IV).   

Much more detailed information about the diagnosis of Wilm’s Tumor can be found here:

• American Cancer Society - http://www.cancer.org/cancer/wilmstumor/detailedguide/wilms-tumor-diagnosis
• Mayo Clinic - http://www.mayoclinic.org/diseases-conditions/wilms-tumor/basics/tests-diagnosis/con-20043492
• Memorial Sloan Kettering Cancer Center - http://www.mskcc.org/pediatrics/childhood/wilms-tumor/diagnosis-staging

Sources:

How are Wilms tumors diagnosed? (2015). Retrieved January 30, 2015, from http://www.cancer.org/cancer/wilmstumor/detailedguide/wilms-tumor-diagnosis     

Wilms' Tumor: Diagnosis & Staging. (2014). Retrieved January 30, 2015, from http://www.mskcc.org/pediatrics/childhood/wilms-tumor/diagnosis-staging

Wilms' tumor. (2015, January 1). Retrieved January 30, 2015, from http://www.mayoclinic.org/diseases-conditions/wilms-tumor/basics/tests-diagnosis/con-20043492

Etiology/ Pathophysiology of Wilm's Tumor

http://www.urologist.com.sg/urology-problem/kidney-cancer.html

What causes Wilm’s Tumor?

Similar to most cancers, the exact cause of Wilm’s Tumors is not known. In general, we know that cancer is a product of DNA mutations that cause cells to grow and divide abnormally. Many studies have been conducted trying to pin point the exact etiology of Wilm’s Tumor. Although no concrete evidence suggests a single cause or mutation in a child’s genetic make-up, some strong associations have been found. Researchers believe that the WT1 gene, which is located on the short arm of chromosome 11, may play a significant role in the development of Wilm’s Tumor. The WT1 gene plays an important role in the normal development of the kidney and urinary system. When the DNA that encodes for the WT1 gene experiences changes (also known as a mutation), the gene cannot function properly, and thus will be unable to carry out its given job in the body.

In addition to mutations in the WT1 gene, researchers have also considered the possibility that Wilm’s Tumor occurs as a result of a disruption of a gene called p53. The p53 gene is a special gene known as a “tumor suppressor” gene. It functions to remind cells to stop dividing and die when their work in the body is done. When the p53 gene is not working, cells are not reminded to stop, and as a result a tumor can develop.

Additionally, certain syndromes can also put a child at higher risk for Wilm’s Tumor. Children with WAGR syndrome (Wilms tumor-aniridia-genitourinary malformation-retardation), Denys-Drash syndrome, and Beckwith-Wiedemann syndrome are all considered to be at higher risk for the development of nephroblastoma.

For much more detailed and in depth analysis of the etiology/ pathophysiology of Wilm’s Tumor go to:

• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3589819/ - article provides a comprehensive overview of Wilm’s Tumor
• http://emedicine.medscape.com/article/989398-overview#aw2aab6b2b3ab1 - website provides an overview of Wilm’s tumor etiology

What is the disease progression?

Wilm’s Tumor, as with most types of cancer, progress through a series of stages. In stage I the tumor is only in one kidney and is able to be completely removed by surgery. In stage II, the tumor has invaded near by tissues and blood vessels, however it can still be completely removed by surgery. In stage III, the tumor has spread beyond the kidney into the abdominal space. In stage III all of the cancer cannot be removed through surgery. In stage IV, the cancer has spread to distant areas of the body such as the brain, lungs, and bones. The later the stage, the farther cancer has spread. As cancer spreads to distant areas of the body, the function of those distant organs are compromised, accounting for the increasing morbidity and mortality as the progression continues. 

Sources:

Davidoff, A. M., & Advances in Pediatrics. (January 01, 2012). Wilms Tumor. Advances in Pediatrics, 59, 1, 247-267.

Disease Information: Solid Tumor: Wilms Tumor. (2015, January 1). Retrieved January 23, 2015. http://www.stjude.org/wilms-tumor

How is Wilms tumor staged? (2014, February 14). Retrieved January 23, 2015, from http://www.cancer.org/cancer/wilmstumor/detailedguide/wilms-tumor-staging

Paulino, A. (2015). Wilms Tumor . Retrieved January 23, 2015, from http://emedicine.medscape.com/article/989398-overview#aw2aab6b2b3ab1

Epidemology of Wilm's Tumor

How common is Wilm’s Tumor? In the general population, it is pretty rare. In fact, Wilm’s Tumor is a disease that almost exclusively affects children. If you work on an adult Med-Surg floor, chances are you may never see this disease. However, if you are a pediatric oncology nurse, Wilm’s Tumor will become a common occurrence in your nursing career.

Percentage of Wilm's Tumor in childhood cancer

What are the statistics? Wilm’s Tumor accounts for 6% of all pediatric cancers, and 95% of all renal tumors in children. Wilm’s tumor will affect 1/10,000 children, with about 500 new cases reported each year.

Who gets Wilm’s Tumor? According to the Society for Pediatric and Perinatal Epidemiology, there are marked ethnic differences in who develops Wilm’s Tumor. Epidemiologic studies suggest that children of Hispanic dissent exhibit lower incidence than those of other ethnicities in the United States. The reasons for these differences are largely unstudied, however research is being done to explore genetic predispositions that account for difference in incidence among populations.  In addition, there are also sex differences in who develops the disease. In the U.S., studies have found that girls experience a higher incidence of Wilm’s Tumor than compared to boys. Additionally, girls tend to be diagnosed closer to their third birthday whereas their male peers tend to be diagnosed closer to their two years of age. The reason for these differences are unknown.

What are the risk factors of Wilm’s Tumor? It is near impossible to pin down what exactly puts an individual at higher risk for Wilm’s Tumor. Studies have suggested that a variety of issues can predispose a child to the disease. Some possibilities include maternal hypertension, maternal exposure to pesticides, and high birth weights. However despite these widespread possibilities, no definitive risk factors have been identified or proven.  

What is the prognosis? Wilm’s Tumor has a mortality rate of approximately 15%. This means that the cure rate (meaning patients are disease free five years after treatment) is incredible. Of those who are treated for Wilm’s Tumor, the five-year survivial is 85%. That is really high!

Interested in learning more? For more info you can read about the epidemiology of Wilm’s Tumor (in much more detail) here: Wilms' tumour: a systematic review of risk factors and meta-analysis (http://onlinelibrary.wiley.com/store/10.1111/j.1365-3016.2010.01133.x/asset/j.1365-3016.2010.01133.x.pdf?v=1&t=i4x7gucd&s=322e48cd07d32afaea0316cea0e47e8435d6ed3f)

Sources:

Chu, A., Heck, J. E., Ribeiro, K. B., Brennan, P., Boffetta, P., Buffler, P., & Hung, R. J. (January 01, 2010). Wilms' tumour: a systematic review of risk factors and meta-analysis. Paediatric and Perinatal Epidemiology, 24, 5, 449-69.

picture: http://www.childrenscancerfund.com/childhood-cancer/default.php?story=61

What is Wilm's Tumor?

CT of normal kidneys. 

CT of child with Wilm's Tumor. 

Have you ever heard of Wilm's Tumor? Most of you will probably say "no." However as a nurse, especially if you will go into pediatrics, you will encounter this disease. Wilm’s Tumor is a rare form of pediatric kidney cancer. However, before delving into the details of kidneys when something has gone wrong, it is important to take a moment to understand the anatomy and the function of a healthy, normal kidney.

A basic overview: The kidneys are located in the upper portion of the abdomen. They sit on the left and right side of the body near the stomach, liver, and pancreas. The kidney has several important jobs. When kidneys function properly, they filter toxins and wastes out of the blood through a series of filtration processes. Additionally, they work with other systems in the body to regulate blood pressure. When kidneys do not function correctly, it sets off a cascade of issues throughout several important systems in the body… but more on that later!

Definition: Wilm's Tumor, also known as nephroblastoma, is a rare form of kidney cancer. Wilm's Tumor most commonly affects young children, usually those between the ages of three to four. Although any cancer diagnosis is devastating, especially when it involves a child, the positive outcomes from this disease are numerous. When diagnosed, it is usually only found in one of the two kidneys. Diagnosis of unilateral disease is good news. The body has two kidneys. However it is possible to survive with only one. Since pediatric cancer is rare, and thus there is no specific screening test to look for such diseases, it is common that the tumor will be quite large upon initial diagnosis. However, in most cases the disease is found and treated before metastasis (spread throughout the body) occurs. When determining the outlook of the disease, it is important to note that there are two types of tumor: that of favorable and that of unfavorable histology. Of the two types, the vast majority (90%) of the Wilm's Tumors are of favorable histology, which means treatment outcomes, on the whole, are very successful.

 Sources:
http://www.cancer.org/cancer/wilmstumor/detailedguide/wilms-tumor-what-is-wilms-tumor http://www.mayoclinic.org/diseases-conditions/wilms-tumor/basics/definition/con-20043492