Clinical significance of pulmonary nodules detected by CT and Not CXR in patients treated for favorable histology Wilms tumor on national Wilms tumor studies-4 and -5: a report from the Children's Oncology Group.

Background: Metastatic lung disease in Wilms tumor (WT) patients was traditionally identified by chest radiograph (CXR). It is unclear whether patients with small lesions, detectable only by computed tomography ("CT-only" lesions), require the more intensive therapy, including doxorubicin and lung irradiation, given to patients with metastases detectable by CXR.

Procedures: This study involved 417 patients with favorable histology WT and isolated lung metastases (detected by CXR or CT) who were registered on National Wilms tumor Study (NWTS)-4 or -5. Outcomes by method of detection (CXR vs. CT-only), use of lung radiation, and 2- or 3-drug chemotherapy (dactinomycin and vincristine ± doxorubicin) were determined and compared using the log-rank test.

Results: There were 231 patients with lung lesions detected by CXR and 186 by CT-only. Of the patients with CT-only nodules, 37 received only 2 drugs and 101 did not receive lung radiation. Five-year event-free survival (EFS) was greater for patients receiving three drugs (including doxorubicin) with or without lung radiation than for those receiving two drugs (80% vs. 56%; P = 0.004). There was no difference seen in 5-year overall survival (OS) between the 3- and 2-drug subsets (87% vs. 86%; P = 0.91). There were no significant differences in EFS (82% vs. 72%; P = 0.13) or OS (91% vs. 83%; P = 0.46) for patients with CT-only nodules whether they received lung radiation or not.

Conclusions: Our results suggest that patients with CT-only lung lesions may have improved EFS but not OS from the addition of doxorubicin but do not appear to benefit from pulmonary radiation.