Wilms tumor

Wilms tumor (nephroblastoma) is a highly malignant embryonal neoplasm that may involve one or both kidneys. Several investigators have reported that the tumor involves the left kidney more frequently than the right, but the reason for this is not known.

Wilms tumor is the fifth most common neoplasm in children. Wilms tumor occurs mostly in young children below the age of 5 years, the peak incidence is 3 years of age. There is equal incidence in boys and girls. The tumor may occur in association with congenital anomalies, whether in the affected child or other family members.

Causes

The occurrence of  Wilms tumor is associated with a genetic inheritance and with several congenital anomalies. Wilms tumors are generally large, rapidly growing lesions that may reach considerable size before they are detected. They develop in the renal parenchyma in either the central or polar location.

Sign and symptoms

• The most common presenting sign of Wilms tumor is the presence of an abdominal mass or an enlarging abdomen. The mass is characteristically firm, nontender, confined to one side, and deep within the flank.
• A Wilms tumor is usually asymptomatic during its early stages. Many times the mass is discovered accidentally by the parents during diaper changing or bathing or may be detected because the child complained of abdominal discomfort. Occasionally the tumor may be an incidental finding when  a physician or nurse examines the child for routine health care or other medical reasons.
• Abdominal pain in later stage of tumor.
• Hypertension (caused by secretion of excess amounts of renin by the tumor)
• Urinary retention or hematuria
• Anemia (caused by hemorrhage within the tumor)
• Pallor, anorexia, and lethargy (resulting from anemia)
• Weight loss and fever
• Symptoms of lung involvement, such as dyspnea, shortness of breath, and pain in the chest, if metastasis has occurred.

Stages of Wilms tumor

• Stage I: Tumor is limited to the kidney and is completely resected. Surface of the renal capsule is intact. Tumor is not ruptured before or during removal, and no residual tumor is apparent beyond the margins of resection.
• Stage II: Tumor extends beyond the kidney but is completely excised. There is regional extension of the tumor, i.e., penetration through the outer surface of the renal capsule into perirenal soft tissues. No residual tumor apparent at or beyond the margins of excision.
• Stage III: Residual nonhematogenous tumor confined to the abdomen. Any one or more of the following occur: (1) Lymph nodes on biopsy are found to be involved in the hilus, the periaortic chains, or beyond. (2) There has been diffuse peritoneal contamination by tumor. (3) Implants are found on the peritoneal surfaces. (4) The tumor extends beyond the surgical margins, either microscopically or grossly. (5) The tumor is not completely resectable because of local infiltration into vital structures.
• Stage IV: Hematogenous metastasis with deposits beyond stage III (i.e., lungs, liver, bone, and brain).
• Stage V: Bilateral renal involvement at diagnosis.

Diagnosis

Abdominal X-ray films, ultrasonography, and CT scan are used to diagnose the Wilms tumor. The definitive diagnosis is made at the time of surgery, when the tumor mass is removed and examined.

Treatment

The therapeutic management of children who have Wilms tumor includes (1) surgical management (2) radiation therapy (3) chemotherapy.

1. Surgical management: Surgery is an extremely important component of total care for these children. Partial or complete nephrectomy for unilateral disease is the surgical treatment of choice.
2.  Radiation therapy: A Wilms tumor that is bilateral or massive may be determined to be inoperable at the time of diagnosis, in which case radiation therapy or chemotherapy may be used. The purpose of preoperative treatment is to cause tumor regression so that surgery can be performed.
3. Chemotherapy: The objectives of chemotherapy are to treat any metastatic lesions that may exist and to destroy any tumor cells in the bloodstream before they become implanted and grow.

Preoperative care

• When the decision for surgery  is made, the parents and child should be prepared for abdominal surgery. In addition, since the tumor tends to be fragile and can rupture and disseminate when palpated, the nurse should explain to parents that they should never palpate the abdomen of their child who is suspected of having Wilms tumor. Caution should be used when turning or otherwise handling the child to avoid putting any pressure on the abdomen. A sign "DO NOT PALPATE ABDOMEN" should be placed on the child's bed to remind everyone of this danger.
• Nurse monitor vital signs, particularly blood pressure.
• Nurse measure abdominal girth at least once daily.

Postoperative care

• Monitor temperature and blood pressure closely.
• Monitor for signs of hemorrhage and infection.
• Monitor strict intake and urine output closely.
• Monitor for abdominal distention; monitor bowel sounds and other signs of gastrointestinal activity because of the risk for intestinal obstruction.