Prognostic factors and long-term results of pulmonary metastasectomy for pediatric histologies.

Objective: Pulmonary resection in metastatic pediatric solid tumors is an accepted method of treatment. The purpose of this study was to determine the clinical course, outcome and prognostic factors after surgery.

Methods: A retrospective analysis from 1985 to 2006 of 52 patients less than 17 years old at the time of tumor diagnosis and submitted to thoracotomy for pulmonary metastatic disease was performed. Three had nodules excised which proved to be benign at histology and were excluded from further analysis. There were 28 males and 21 females with median age of 13.2 years [2-36] at the time of metastasectomy. The primaries were osteosarcoma (25), Ewing's sarcoma (6), Wilms' tumors (4), hepatoblastoma (3) and miscellaneous (11). Pulmonary metastases were encountered either at the time of initial diagnosis (18%) or occurring within 1 month to 22 years. Disease free interval (DFI) was equal or less than 2 years in 31 (63%) patients and more than 2 years in 18 (37%).

Results: Patients had one (24), two (16), three (2), four or more (7) metastasectomies resulting in a total of 95 thoracotomies. Wedges (75%) were performed more frequently than anatomic resections (25%). The number of resected metastatic nodules ranged from 1 to 45, median 3. There were no perioperative deaths. There were six complications: pneumothoraces requiring chest tube drainage in two cases. Resection was incomplete in four cases. The mean drainage time and hospital length of stay were 2.7 and 5 days, respectively. Using the date of pulmonary resection as the starting point, 5-year survival rate was 25%. By univariate analysis, we found that a significantly longer survival was observed for patients with a complete resection (p=0.004), with two or less metastases (p=0.0004), with unilateral metastases (p=0.001) or when the DFI was more than 2 years (p=0.003). By multivariate analysis, we showed that the number of pulmonary metastases was an independent predictor of survival.

Conclusion: We conclude that resection of pulmonary metastases of pediatric solid tumors is a safe and effective treatment that offers improved survival benefit in carefully selected patients within a multidisciplinary approach for pediatric cancer. Prognosis related criteria that support patient selection for surgery are identified.