Nephroblastoma is a type of cancer which develops in the kidneys. This cancer is also called Wilms tumor, and is the most common type of kidney cancer to develop in children. In the 1950s and 1960s, most children with nephroblastoma had a very poor prognosis, but treatment for the cancer has advanced significantly in the intervening decades. The success rate for Wilms tumor treatment is now approximately 90%, largely due to the practice of combining surgery with radiotherapy or chemotherapy.
Nephroblastoma has a global incidence rate of 0.8 cases per 100,000 people. Most children with this cancer are diagnosed between three and four years of age. Children commonly have tumors in one kidney only; in around 6% of cases tumors grow in both kidneys. Typically the development of the cancer is spontaneous; however, sometimes it may arise as part of a syndrome such as congenital aniridia, in which the risk of Wilms tumor is linked to eye disorders such as cataracts and glaucoma. Susceptibility to this type of cancer can also be genetically inherited, although increased susceptibility does not guarantee that a given individual will develop the cancer.
Many types of cancer are caused by mutations in tumor suppressor genes. These are genes which, when functioning correctly, reduce the risk of cells turning cancerous. Many different genes, with a wide range of functions, can act as tumor suppressor genes. The gene which is linked to nephroblastoma is active during fetal kidney development, but is relatively inactive after birth. A mutation in this gene promotes cellular changes which can cause the development of a Wilms tumor.
Common symptoms of nephroblastoma are abdominal pain, and the presence of a lump in the abdomen. Many children also have fever, anemia, or blood in the urine. Possible complications include metastasis, which commonly occurs in one lung. In addition, a Wilms tumor is at risk of rupturing, which can lead to kidney hemorrhage and dispersion of cancer cells throughout the abdomen.
Children diagnosed with Wilms tumors usually undergo surgery to remove the tumor, or, if necessary, an entire kidney. This surgery is followed by chemotherapy to ensure that all cancer cells are killed. In rare cases, radiation therapy may be used as a follow-up treatment instead. Generally, however, the established protocol for treating this cancer is surgery and chemotherapy with a specific set of drugs. The chemotherapy agents most often used to treat the cancer are doxorubicin, vincristine, and Dactinomycin®.