According to EURAMOS-1, 17% of osteosarcoma patients were considered to have metastases at diagnosis. In this selected cohort, the reported 5-year EFS from diagnosis of 28% compares well to previous results reported from unselected cohorts of patients with only lung metastases. Resection of pulmonary metastases from osteosarcoma is a treatment option which has been shown to correlate with survival benefit and cure in select individuals. These patients are best addressed in a multidisciplinary fashion, with the involvement of a thoracic surgeon with experience in pulmonary metastasectomy. At the same time, the goal of surgical resection of pulmonary metastases from osteosarcoma is to render the patient completely disease free. "Tumor debulking" or "cytoreductive surgery" with incomplete resection has not demonstrated any survival benefit for patients with pulmonary metastases. Thus open thoracotomy is more preferred than VATS. However over the last decade in China, thoracotomy has not been adopted generally. More patients had chosen VATS or even hypo-fractionation radiotherapy, such as gamma knife, cyber knife and so on as a local treatment method. This study aims to investigate the survival of consecutive patients who had achieved a first complete surgical remission (CR) during combined-modality therapy on neoadjuvant or adjuvant PKUPH-OS protocol so as to discuss reasonable local therapy for resectable pulmonary osteosarcoma metastatic lesions.

Inclusion Criteria:

• Histologically confirmed high-grade osteosarcoma reviewed by the Pathology Committee of Peking University People's Hospital
• Pulmonary nodules by Chest CT confirmed by later scan as pulmonary metastasis
• A first complete remission (CR) had been achieved
• Intended first-line treatment included pre- and postoperative chemotherapy according to the PKUPH-OS protocol as well as local therapy of all operable lesions

Exclusion Criteria:

• Lost to follow up
• Patients with severe or uncontrolled medical disorders that could jeopardize the outcomes of the study. These confounding conditions included, cardiac clinical symptoms or disease with left ventricular ejection fraction<50%, and hypertension that could not be well controlled with antihypertensive drugs.

This report includes all the patients with recurrences from a previously treated cohort of 678 consecutive, newly diagnosed patients with localized or primary metastatic high-grade osteosarcoma of the trunk or limbs registered onto the neoadjuvant studies of Peking University People's Hospital and Peking University Shougang Hospital between the end of 2009 and March 2020. Intended first-line treatment included pre- and postoperative chemotherapy according to the PKUPH-OS protocol , as well as surgery of all operable lesions. All protocols prescribed high-dose methotrexate, doxorubicin, cisplatin and ifosfamide in varying combinations.