Objective: Background: Osteosarcoma is the most prevalent primary bone cancer in adolescents and young adults, often complicated by pulmonary metastases which worsen prognosis. The clinical implications of sub-centimetric lung nodules (less than 1 cm) remain uncertain, prompting this study to assess their long-term outcomes.
Methods: This retrospective analysis spanned January 2016 to December 2022 and involved 213 extremity osteosarcoma patients from a prospectively maintained database. Only those with initial chest CT scans showing nodules smaller than 1 cm were included. Data on patient age, osteosarcoma site, and histology were collected. Follow-up scans were reviewed after neoadjuvant chemotherapy (NACT), post-adjuvant chemotherapy, and annually. Patients were categorized based on nodule response post-NACT into progressed, regressed, or static groups, and survival outcomes were analyzed.
Results: At diagnosis, 18.8% of patients (40/213) presented with indeterminate lung nodules (ILN). The majority (80%, 32/40) had nodules smaller than 5mm, primarily unilateral. Post-NACT, 26.3% (10/38) exhibited increased nodule size or number, of whom 90% showed further progression over a median follow-up of 10.2 months. Conversely, 18.4% (7/38) displayed a decrease in nodule size or number, with 42.9% progressing later over a median of 24.3 months. Static nodules were observed in 47.4% (18/38), with 55.6% showing progression. No significant differences in disease-free survival (DFS) or overall survival (OS) were noted between patients with unilateral versus bilateral nodules.
Conclusion: Indeterminate lung nodules in osteosarcoma patients pose significant challenges in clinical management, with a high likelihood of progressing to metastasis. Stringent monitoring and timely intervention are crucial for potentially improving patient outcomes.
