Effect of timing of pulmonary metastasis occurrence on the outcome of metastasectomy in osteosarcoma patients

Background: Complete metastasectomy is the best predictor of survival in patients with osteosarcoma pulmonary metastases. There has been some controversy in the literature regarding the prognostic significance of the timing of occurrence of lung metastasis. Methods: We reviewed the clinical course of all osteosarcoma patients with pulmonary metastases treated by metastasectomy in our hospital from January 2008 through December 2016. Each patient who underwent metastasectomy was placed into one of three groups based on whether lung metastases were present at initial presentation (Group 1), developed during chemotherapy (Group 2), or appeared after completion of chemotherapy (Group 3). Data were obtained retrospectively and follow-up was obtained until the end of June 2017. Results: We identified 170 patients with pulmonary nodules of whom 99 (58.2%) underwent at least one metastasectomy (149 thoracotomies). Eleven patients had benign pulmonary nodules and were excluded. The other 88 patients were classified as Group 1 (37), Group 2 (18) or Group 3 (33). The median follow-up was 35 months (range 8 to 99). Postmetastasis 5-year overall survival (OS) was 38.1 +/- 6.4%; event-free survival (EFS) was 25 +/- 5.3%. By group, postmetastasis 5-year OS and EFS were 34.3 +/- 13% and 18 +/- 9.3% in Group 1, 8 +/- 6.5% and 6.5 +/- 5% in Group 2, and 52 +/- 11.4% and 25 +/- 9% in Group 3 (P < 0.001). In univariate analysis, the only significant factors associated with survival were timing of occurrence of lung metastasis and the number of lung nodules found. Conclusion: The timing of occurrence of lung metastasis is an important prognostic factor among osteosarcoma patients eligible for metastasectomy. Patients whose metastases occurred during chemotherapy had the worst survival. (C) 2018 Elsevier Inc. All rights reserved.