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Use of Chest Computed Tomography for Staging and Treatment of Wilms’ Tumor in Children

Roswell Park Cancer Institute, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY

IN THIS ISSUE OF the Journal of Clinical Oncology, Owens et al¹ report the results of a retrospective study correlating findings on computed tomography (CT) of the chest with outcome of children with renal tumors. Twenty-two of the 141 children included in this review had pulmonary nodules at initial diagnosis that were visible only on the chest CT scan. The percentage of patients who subsequently experienced pulmonary relapse was not significantly different from the percentage of patients who relapsed and had a negative chest CT scan, after they were treated with therapy appropriate for the stage of their abdominal tumor and without pulmonary irradiation. However, when the analysis was restricted to children with stage I tumors, a group treated with vincristine alone in the United Kingdom, the pulmonary relapse rate was significantly higher in those with a positive chest CT scan at diagnosis than in those with a negative chest CT scan. The authors suggest that a randomized trial would be needed to determine whether this group of patients would benefit from combination, rather than single-agent, chemotherapy.¹

The management of Wilms’ tumor patients with pulmonary nodules identified only on the chest CT scan has been the subject of other studies. Interobserver variability in the interpretation of chest CT scans has been studied in pediatric patients with Wilms’ tumor and with Hodgkin’s disease. In the study reported by Wilimas et al,² 78 of 202 chest CT scans were interpreted as positive by at least one reviewer, 18 by two reviewers, and only 19 (24%) by all three of the reviewers. The cumulative pulmonary relapse rate was 13% to 20% in the patients with a positive chest CT scan, depending on the reviewer.² In a review of 31 separate sites on 59 chest CT scans obtained for pretreatment staging of Hodgkin’s disease in pediatric patients, Fletcher et al³ reported concordance by four of the five raters of greater than 90% for only five sites and less than 80% for 13 sites. No study has correlated histopathologic findings with chest CT abnormalities in a consecutive series of prospectively evaluated children with Wilms’ tumor or Hodgkin’s disease. Thus, at the present time, the percentage of identified lesions that represent malignant disease is not known.

Previous studies have been criticized because of the retrospective nature of the review, lack of central review of radiographs, lack of a uniform imaging protocol, and nonuniform management of patients with pulmonary metastases. The present study is the result of a central review of radiographs obtained, using a defined imaging protocol, from a subgroup of patients registered on the second United Kingdom Children’s Cancer Study Group Wilms’ Tumor Study. The authors demonstrate that the stage, age, and histopathologic subtype distributions did not differ between the group that underwent chest CT and that which did not. The percentage of patients with a positive chest CT scan and negative plain chest radiograph was 22%. This is similar to the percentages reported by the three diagnostic image reviewers (12.9%, 18.0%, and 35.8%) in the study by Wilimas et al.² None of the present patients underwent open-lung biopsy to confirm the malignant nature of the pulmonary nodules.

Owens et al¹ report no difference in prognosis between the groups with positive or negative chest CT scans. This finding is similar to that of Meisel et al.⁴ However, Meisel et al identified an increased risk of death for patients with positive CT scans and stage III primary tumors, compared with those with stage III primary tumors and no pulmonary metastases on CT scan. This finding contrasts with that of Owens et al, who report a poorer prognosis for those with stage I tumors and CT-only lesions when treated with vincristine alone and without whole-lung irradiation. This result suggests that these recurrences were not responsive to secondary treatment, a finding that is at variance with the results of treatment of relapse of children with small stage I favorable histology Wilms’ tumor treated initially with nephrectomy alone.⁵

The risks of more aggressive treatment, such as the addition of doxorubicin to the chemotherapy regimen and the administration of whole-lung irradiation, include an increase in the relative risk of a second malignant neoplasm,⁶ the risk of diffuse interstitial pneumonitis,⁷ and the risk of congestive heart failure.⁸ These risks must be considered carefully when one contemplates the use of additional agents for the management of children with abnormalities noted only on chest CT scan.

At present, most physicians who treat children with Wilms’ tumor and pulmonary nodules detected only on chest CT scan believe they know how to manage these children—although what they know varies. Some are convinced that pulmonary irradiation is necessary only if the open-lung biopsy result is positive, some perform no lung biopsies and do not use whole-lung irradiation, and some use whole-lung irradiation in the absence of a tissue diagnosis of metastatic disease. Some argue that a randomized study to answer this question is not necessary as all of these patient populations have an excellent prognosis.

Chest CT for staging Wilms’ tumor in children can be justified only if the information obtained is reliable, correlates with prognosis, and results in administration of different treatment than would have been recommended in the absence of the chest CT scan, and if the outcome of treatment is favorably influenced by the information obtained. At present, adequate data to address these issues do not exist. A well-conducted, prospective, randomized study of the role of whole-lung radiation therapy in patients with biopsy-proven CT-only pulmonary metastases could assist in the management not only of children with Wilms’ tumor, but also those with other malignant solid tumors, where questions such as the relationship between volume of metastatic disease, treatment regimen, and treatment outcome have yet to be addressed.

ACKNOWLEDGMENTS

Supported in part by Public Health Service grant nos. CA-54498 and CA-42326.

REFERENCES

1. Owens CM, Veys PA, Pritchard J, et al: Role of chest computed tomography at diagnosis in the management of Wilms’ tumor: A study by the United Kingdom Children’s Cancer Study Group. J Clin Oncol 20: 2768-2773, 2002[Abstract/Free Full Text]

2. Wilimas JA, Kaste SC, Kauffman WM, et al: Use of chest computed tomography in the staging of pediatric Wilms’ tumor: Interobserver variability and prognostic significance. J Clin Oncol 15: 2631-2635, 1997[Abstract/Free Full Text]

3. Fletcher BD, Glicksman AS, Gieser P: Interobserver variability in the detection of cervical-thoracic Hodgkin’s disease by computed tomography. J Clin Oncol 17: 2153-2159, 1999[Abstract/Free Full Text]

4. Meisel JA, Guthrie KA, Breslow NE, et al: Significance and management of computed tomography detected pulmonary nodules: A report from the National Wilms Tumor Study Group. Int J Radiat Oncol Biol Phys 44: 579-585, 1999[CrossRef][Medline]

5. Green DM, Breslow NE, Beckwith JB, et al: Treatment with nephrectomy only for small, stage I/favorable histology Wilms’ tumor: A report from the National Wilms’ Tumor Study Group. J Clin Oncol 19: 3719-3724, 2001[Abstract/Free Full Text]

6. Breslow NE, Takashima JR, Whitton JA, et al: Second malignant neoplasms following treatment for Wilms’ tumor: A report from the National Wilms’ Tumor Study Group. J Clin Oncol 13: 1851-1859, 1995[Abstract/Free Full Text]

7. Green DM, Finklestein JZ, Tefft M, et al: Diffuse interstitial pneumonitis after pulmonary irradiation for metastatic Wilms’ tumor: A report from the National Wilms’ Tumor Study. Cancer 63: 450-453, 1989[CrossRef][Medline]

8. Green DM, Grigoriev YA, Nan B, et al: Congestive heart failure after treatment for Wilms’ tumor: A report from the National Wilms’ Tumor Study Group. J Clin Oncol 19: 1926-1934, 2001[Abstract/Free Full Text]

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This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Save to my personal folders Download to citation manager Rights & Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Green, D. M. Search for Related Content PubMed PubMed Citation Articles by Green, D. M. Social Bookmarking                            What's this?