Indeterminate nodules in osteosarcoma: what's the follow-up?

Background: Indeterminate pulmonary nodules in patients diagnosed with osteosarcoma present a challenge for accurate staging and prognosis. The aim of this study was to explore the significance of this finding. Methods: A retrospective cohort study of 120 patients with osteosarcoma was performed in the North East of England. Chest computed tomographies (CTs) at presentation were reviewed and the incidence of 'indeterminate' nodules recorded. Follow-up scans were reviewed and survival as well as prognostic features were analysed. Results: 25% of our cohort presented with indeterminate nodules. Of these, 33% were subsequently confirmed as metastases, the majority within a year. Kaplan-Meier survival analysis showed that patients with indeterminate nodules fared better than those with frank metastatic disease, and similar to those who presented with a normal chest CT. We found no radiographic features that predicted survival. Conclusions: Indeterminate nodules remain a clinical and diagnostic dilemma. Close monitoring of patients is advised during the first year from presentation, and there is potential for indeterminate nodules to develop into frank metastases later than five years from presentation.