In our article, we investigated the clinical course of patients with osteosarcoma after the patients develop lung metastasis, dividing the patients into four groups, depending on timing of identification of lung metastases.1 Few data exist on the literature about the effect of relapse of pulmonary metastatic disease from osteosarcoma on patient survival.2 Unfortunately, Professor Briccoli did not report the total survival of the 65 patients of recurrent pulmonary metastases reported in his letter. However, the data supplied by Professor Briccoli would be complementary to our data and an addition toward better understanding of the factors affecting the survival of osteosarcoma patients with pulmonary metastases at different stages of their disease. This might help to detect patients who are good candidates for metastasectomy. Unfortunately, our article is a multicenter study, and the questionnaire did not include sufficient data about the relapse of lung metastases, so we could not confirm the reproducibility of results obtained by Professor Briccoli on patients of our study. To answer his comments, timing of local recurrence of the primary tumor should also be considered.