Treatment of Wilms Tumor
Table 3. Overview of Wilms Tumor Standard Treatment by Stage continued...
For patients with stage IV FH Wilms tumor, the role of pulmonary irradiation has been examined retrospectively (based on chest x-ray results) and is being examined prospectively (based on CT scan results) to identify clinical and radiologic features in patients that suggest that radiation can be omitted in certain subsets.
Investigators in the United Kingdom reviewed outcomes in children with stage IV Wilms tumor with pulmonary metastases at diagnosis and the factors that contributed to the decision to withhold pulmonary radiation. Patients who underwent pulmonary irradiation had a 9-year EFS of 79% versus 53% in patients who did not, although there was no difference in OS. Pulmonary radiation decreased the chance of lung relapse (8% vs 23%). No consistent features could be identified to aid in the selection of patients who could safely avoid pulmonary radiation.
In a retrospective review of newly diagnosed patients with Wilms tumor and pulmonary metastases enrolled on the SIOP-93-01 and SIOP-WT-2001 studies, the 5-year OS was 83% and the 5-year EFS was 72% for all children (N = 207). Survival was poorer for high-risk primary tumor histology patients (5-year OS 44%, EFS 39%) than for low- and intermediate-risk patients (5-year OS 90%, EFS 77%). Complete response of patients with pulmonary metastases to 6 weeks of chemotherapy was associated with better outcome (5-year OS 91%, 5-year EFS 79%) compared with patients with stable or progressive disease (5-year OS and EFS 17%). The presence of viable tumor in the resected pulmonary metastases was associated with a poorer survival (5-year OS 55%, 5-year EFS 35%) compared with completely necrotic metastases (5-year OS 97%, 5-year EFS 85%). Of patients whose pulmonary lesions showed a complete remission to chemotherapy alone, approximately 20% relapsed.
The presence of liver metastases at diagnosis is not an independent adverse prognostic factor in patients with stage IV Wilms tumor.
Stage V and those predisposed to developing bilateral Wilms tumor
Management of a child with bilateral Wilms tumor is very challenging. The goals of therapy are to eradicate all tumor and to preserve as much normal renal tissue as possible, with the hope of decreasing the risk of chronic renal failure among these children. Traditionally, patients have undergone bilateral renal biopsies with staging of each kidney. In NWTS-4, bilateral Wilms tumor patients had a lower EFS and OS compared with patients with localized Wilms tumor (including anaplastic histology), except for stage IV patients, in which OS was higher for patients with bilateral Wilms. The NWTS-4 study reported that the 8-year EFS for patients with bilateral Wilms tumor with favorable histology was 74% and the OS was 89%; for anaplastic histology, the EFS was 40% and OS was 45%. The NWTS-5 (COG-Q9401) study reported the 4-year EFS for bilateral Wilms tumor patients was 61% and the OS was 81%; with anaplastic histology, the EFS was 44% and the OS was 55%.[2,3] Similar outcomes for patients with bilateral Wilms tumor have been reported in a single-institution experience in the Netherlands, with a 10-year OS of 78% (N = 41). In this study, there was significant morbidity in terms of renal failure (32%) and secondary tumors (20%). The incidence of end-stage renal failure in the Dutch study may be a reflection of a longer follow-up period.