Newly DiagnosedWilms tumor is the most common form of kidney cancer in children. It is also called nephroblastoma. "Nephro" means kidney, and a "blastoma" is a tumor made of embryonic tissue that has not yet fully developed. About 500 children are diagnosed with Wilms tumor in the United States each year and about 75% of those patients are under 5 years old. Children diagnosed with Wilms Tumor or other kidney tumors may have experienced the some following symptoms:
Approximately 15% of kidney tumors in childhood are not Wilms tumor. To diagnose kidney tumors, doctors need information about the types of cells that make up the tumor. It is important to correctly identify these tumors because they are treated differently from Wilms tumor. The second most common kidney tumor is clear cell sarcoma of the kidney (CCSK). The symptoms, diagnostic tests and methods of treating CCSK are quite similar to those of Wilms tumor. Characteristics of clear cell sarcoma include:
There are many procedures and tests to see if and where cancer cells are present in the body. The exact combination of testing used to diagnose a child depends on the symptoms that are present and the suspected type of cancer. Typically, cases of Wilms tumor are not diagnosed until the tumor becomes quite large. Fortunately, most tumors are discovered before they metastasize (spread to other organs in the body). As with many cancers, the tumor mass can become quite large; the average weight of a newly discovered tumor is about 500 grams (one pound), which is larger than the normal kidney. In addition to a complete medical history and physical examination, diagnostic tests are performed to evaluate the kidney tumor and look for signs of spread to other areas of the body.
These tests also enable the treating doctors and surgeons to select the best approach for treatment because they show where the tumor is located. The diagnosis is usually confirmed by the surgical removal of all or part of the tumor when a pathologist examines it under a microscope. In some cases, it is not advisable to perform surgery because it might be dangerous for the child. In these cases, treatment with chemotherapy will be started to shrink the tumor and make removal safer at a later time. The prognosis (chance of recovery) for children with Wilms tumor is generally very good. Currently, the great majority of children with Wilms tumor are cured. The overall five-year survival rate for children with Wilms tumor is approximately 90%. That means that 9 out of 10 children with Wilms tumor will live at least five years after their cancer is diagnosed. The five-year survival mark is the point at which a patient is considered "cured" since these tumors almost never recur after that time. There are two major types of Wilms tumors. These are identified based upon the types of cells that are found (histology) and impact the outcome. After the tumor or a portion of the tumor is removed, a pathologist will identify the type of cells that make up the tumor. Wilms tumor of favorable histology If a tumor has unfavorable histology, it means that the cells are more abnormal and that the nuclei of the cancer cells (the part that contains the cells' DNA) are very large and distorted. This is called anaplasia. Anaplasia is more resistant to chemotherapy treatment, and therefore the chances of a cure are lower. Wilms Tumor StagingAfter making a diagnosis of Wilms tumor, doctors need to assess how advanced the tumor is, including:
This is called “staging” the tumor. Staging allows the cancer care team to identify the best treatment approach using a combination of chemotherapy, surgery and radiation therapy. It will also provide information about the outlook for cure. The staging system used to describe the extent of spread of Wilms tumors was developed by the National Wilms Tumor Study Group (NWTS) and updated by the Children’s Oncology Group Renal Tumor Committee. The NWTS/COG system describes Wilms tumor stages using Roman numerals I through V (1 to 5). Stage I About 40% of all Wilms tumors are stage I. Stage II The cancer grew beyond the kidney, but was completely removed surgically without any apparent cancer left behind. One or more of the following features may be present:
About 20% of all Wilms tumors are stage II. Stage III This stage refers to Wilms tumors that have not been completely removed. The cancer remaining after surgery is limited to the abdomen. One or more of the following features may be present:
About 20% of all Wilms tumors are stage III. Stage IV About 10% of all Wilms tumors are stage IV. Stage V About 5% of all Wilms tumors are stage V. Last updated July, 2011About Kidney/Wilms TumorIn Treatment for Kidney/Wilms Tumor After Treatment of Kidney/Wilms Tumor |