(P 93) INDETERMINATE CHEST LESIONS IN PATIENTS WITH BONE SARCOMA INCIDENTAL FINDING VERSUS METASTATIC DISEASE

Objective: To identify the frequency of benign pulmonary nodules versus true metastatic disease in adult patients with a bone sarcoma and to identify what factors predict the progression of indeterminate pulmonary nodules to true metastatic disease.

Methods: This was a retrospective cohort study of adult patients presenting with a bone sarcoma at a single institution from 2010-2020. Patients were excluded if they had known metastatic disease at time of diagnosis, underwent a non-oncologic surgery or had incomplete staging and surveillance imaging with CT scan. Demographic variables, oncologic variables (histology, grade) and variables associated with indeterminate nodules (size, number) both at presentation and follow up were collected. Descriptive statistics were used to summarize variables of interest and regression analyses performed to look at associations of progression of indeterminate nodules to metastatic disease versus those that did not.

Results: Less than half of patients that presented with indeterminate nodules progressed to metastatic disease (41%). Of patients that developed new nodules during surveillance 55% progressed to metastatic disease. Number and size of nodules at presentation was not associated with progression of nodules to metastatic disease.

Conclusion: Less than half of patients with indeterminate nodules at presentation will progress to metastatic disease and about half of patients that develop new nodules on surveillance will progress to metastatic disease.