Wilms tumor (WT), excellently reviewed in the April issue of Pediatrics in Review by Dr. Valerie Smith et al, is the most common renal malignancy and the second most common intra-abdominal tumor of childhood. That being said, as with all childhood cancers, it is very rare, and it is possible for a pediatrician to go through an entire career without encountering a child WT. Nationwide there are about 600 cases of WT each year, which equates to an incidence of 20 cases/106 children per year at the peak age of WT at four years old. WT is very rare after age six. This incidence is less than the overall incidence of cancer in children younger than 20 years old (160–180 cases/106 per year), and far less than the incidence of cancer in the overall US population (mainly adults) of 400–500 cases/100,000 per year.
The pediatrician has a crucial role in early care of the child with WT, and, for that matter, all children with cancer diagnoses. From the perspective of the subspecialist, the primary care provider or pediatrician is responsible for maintaining a very high index of suspicion with early referral to the pediatric oncologist for evaluation and treatment.
As pointed out by Smith et al, it is also important for the general pediatrician to be aware of the congenital anomalies thar predispose a child to the development of WT, most notably Beckwith-Wiedemann, Denys-Drash, WAGR, and overgrowth syndromes, and coordinate with the geneticist or hematologist/oncologist for routine abdominal ultrasound screening that can help in early diagnosis, increasing the chance of cure.
WT is highly treatable and is curable in most cases, for all but the most aggressive tumors, which fortunately are the minority. This treatment currently involves combinations of surgery, chemotherapy, and radiation therapy, with the intensity of treatment determined by how aggressive the tumor is based on histology, stage, and genetic markers. This risk adaptive therapy has been responsible for improvements in disease-free survival over the last three to four decades.
After completion of therapy, the pediatrician will again assume primary care of the child with WT and must again be the eyes and ears for the subspecialist. The child will generally have had a nephrectomy and receive treatments as described above. The pediatrician must be aware of the long-term issues that exposure to the patient’s specific therapy may predispose them to. This may involve subspecialists other than the pediatric oncologist. For this purpose, the reader is directed to the Children’s Oncology Group long-term follow-up guidelines.
