Prognostic factors and imaging patterns of recurrent pulmonary nodules after thoracotomy in children with osteosarcoma

BACKGROUND: In children with osteosarcoma who have undergone thoracotomy, it often is difficult to distinguish metastatic from benign recurrent pulmonary nodules. The authors of this study sought to identify any computed tomography (CT) imaging pattern of recurrent pulmonary metastases in this patient population. The authors also sought to identify associated prognostic factors. METHODS: CT scans obtained after thoracotomy were available for 35 patients with osteosarcoma who had undergone resection of presumed pulmonary metastases at St. Jude Children's Research Hospital (Memphis, TN). CT scans obtained before the initial thoracotomy were available for 33 of the 35. The authors recorded location, histologic diagnosis, and time of development of the original pulmonary nodules, time of recurrence of pulmonary disease; the location of recurrent nodules, and the presence of calcification, adenopathy, or progressive pleural disease, as well as patient demographic data, survival data, and location of the primary tumor site. RESULTS: Pulmonary nodules recurred in 32 of the 35 patients after thoracotomy. Nineteen of these patients underwent resection of the recurrent lesions and 1 who died underwent an autopsy; 18 of the 20 patients had metastatic disease. The only CT finding consistently associated with recurrent metastatic disease was progressive pleural thickening, which predicted a poor outcome. The occurrence of a solitary pulmonary nodule in the lung contralateral to the previous surgery was associated almost always with a benign process. CONCLUSIONS: CT imaging cannot distinguish reliably between benign and metastatic recurrent pulmonary disease after thoracotomy in patients with osteosarcoma. Recurrent pulmonary disease in this set of patients is likely to be metastatic, and aggressive surgical intervention is probably warranted. In this study, patients who had progressive pleural disease after thoracotomy consistently experienced pulmonary metastatic recurrence and had a poor prognosis.